Bohannon Huston Site Electrical Infrastructure Master Plan

NEW MEXICO STATE UNIVERSITYLAS CRUCES, NM

SITE ELECTRICAL INFRASTRUCTUREMASTER PLAN

DRAFT

July 7, 2014

August 29, 201414094

NEW MEXICO STATE UNIVERSITYLAS CRUCES, NM

SITE ELECTRICAL INFRASTRUCTUREMASTER PLAN

DRAFT

July 7, 2014

August 29, 2014Volume 1 - Report

New Mexico State University

Site Electrical Infrastructure Master Plan

Table of Contents August 27, 2014

Page TC-1

Table of Contents

Volume 1 Report

CHAPTER I - Executive Summary .............................................................................................................. 1

CHAPTER II Introduction ......................................................................................................................... 2

A. New Mexico State University, Background ............................................................................ 2-1

B. Need for an Electrical Infrastructure Master Plan ................................................................. 2-2

C. Project Approach ........................................................................................................................ 2-4

D. Exclusions .................................................................................................................................... 2-5

E. Acknowledgements .................................................................................................................... 2-6

CHAPTER III Existing System .................................................................................................................. 3

A. Definition of Terms and Abbreviations ................................................................................... 3-1

B. Field Investigation ...................................................................................................................... 3-1

C. Serving Utility and Campus Substations ................................................................................. 3-2

D. Cogeneration .............................................................................................................................. 3-2

E. 25kV and 5kV systems ............................................................................................................... 3-2

F. Circuits ......................................................................................................................................... 3-3

G. Load and Capacity of the Electrical Distribution System ...................................................... 3-6

H. Equipment and Cabling ........................................................................................................... 3-10




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I. Emergency and Standby Systems .......................................................................................... 3-11

J. Building Types / Categories..................................................................................................... 3-12

CHAPTER IV Reliability Analysis ............................................................................................................. 4

A. General ........................................................................................................................................ 4-1

B. IEEE 497 ....................................................................................................................................... 4-1

C. Evaluated System Configurations ............................................................................................ 4-3

D. Reliability Data ............................................................................................................................ 4-4

E. Results of the Reliability Calculations ...................................................................................... 4-5

F. Analysis and Observations ........................................................................................................ 4-6

G. Building Priority List ................................................................................................................... 4-9

H. Reliability Guidelines ............................................................................................................... 4-18

CHAPTER V Recommendations ............................................................................................................. 5

A. General ........................................................................................................................................ 5-1

B. Recommendations List .............................................................................................................. 5-1

C. Other Recommendations ........................................................................................................ 5-19

D. Cost Summary of Recommendations .................................................................................... 5-20

CHAPTER VI Drawings ............................................................................................................................. 6




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Volume 2 Appendices (See each appendix for content)

A. Appendix A Field Investigation Equipment (Abbreviated)

B. Appendix B Meter Data Graphs

C. Appendix C Building Master Data Sheet

D. Appendix D Reliability Calculations

E. Appendix E Cost Estimates

F. Appendix F Meeting Notes

Volume 3-1 - Appendix A Switchgear

Volume 3-2 - Appendix A 25kV Transformers

Volume 3-3 - Appendix A 5kV Transformers

Volume 3-4 - Appendix A Building Secondary Feeders

Chapter 1

Executive Summary



Table of Contents July 7, 2014

Page TC-1

New Mexico State UniversitySite Electrical Infrastructure Master PlanChapter 1 - Executive Summary

August 29, 2014



Chapter 1 Executive Summary August. 29, 2014

Page 1-1

I. EXECUTIVE SUMMARY

In February of 2011, Las Cruces, NM experienced a sustained power outage that

crippled operations in the area for several days. It was a result of unusually cold

weather in the region causing a shortage in natural gas supply which is used to fuel

utility power generators. The outage affected many consumers, including the New

Mexico State University (NMSU) Las Cruces campus. Just a few weeks later, U. S. Senate

hearings were held concerning the outage, and an opening statement by NM Senator

Jeff Bingham described the impact that such an outage has on consumers: utility

consumers rely greatly on these energy systems. Ultimately it's these customers who

bear the heaviest burden and pay the heaviest costs of long lasting service disruptions.

That's certainly what happened in this case. During the outage, NMSU was forced to

make substantial cuts in electrical load and run on the limited capacity of its one on-

campus turbine generator. The campus was essentially shut down until normal power

was restored. The outage, while very unusual, was a harsh reminder of our dependency

on reliable electrical power for everyday operations.

This Site Electrical Infrastructure Master Plan is in response to a request made by NMSU

in February of 2013 for a master plan to review the campus electrical infrastructure,

make recommendations to improve system reliability and reduce the dependency on

the outside utility to provide power to the more critical buildings on campus involving

data center operations, research, and important student operations. The main

objectives of the master plan effort include the following:

Increase reliability in the campus electrical distribution system. Explore the use of the campus turbine generator as a reliable, alternative source

of power for more critical buildings.

Phase out the older 5 kV campus voltage and convert to all 25 kV distribution. Address immediate projects and provide direction for connections to the campus

distribution system, in coordination with long-term goals of the master plan.

Plan for future growth and flexibility to accommodate projects for the next 15 20 years.

Efforts to develop the plan began in August of 2013 and involved the combined

engineering teams of Bohannan Huston, Inc. and Spectrum Engineer, Inc. A project




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approach was developed that has proven to be successful on master planning efforts

used on other campuses to evaluate and increase the level of reliability in the electrical

infrastructure. This approach included the following elements:

Design meetings or charrettes were held with the engineering team and NMSU personnel in order to share information, receive valuable input, and develop

ideas that could potentially meet the objectives of the project.

Field Investigation / Data Acquisition: The engineering team gathered available data and investigated the existing system during a period of 2 -3 months,

resulting in a 2,200 page compilation that includes equipment inventory, photos

and field notes. This effort proved to be a valuable resource in developing

recommendations, and should continue to be a resource for the campus

operations and maintenance moving forward.

Reliability Analysis: Unique to this approach, differing from most other electrical planning efforts, is the use of statistical probability to calculate the relative

reliability of the existing system, and evaluate the different options for system

improvements. The calculations for this study follow The IEEE Std. 493-1997,

IEEE Recommended Practice for the Design of Reliable Industrial and Commercial

Power Systems, or the Gold Book. The results of this analysis provided hard

numbers that represent the level of reliability of the existing system compared

to the recommended improvements. This data can then be used to make better

informed decisions to spend available funds on the projects that will result in the

greater increase in reliability. More significant results of this analysis that are

relevant to specific interests at NMSU, some of which may be expected and

some not, include the following:

Of all components of the electrical distribution system, the utility source

supply, regardless of the specific utility provider, is the least reliable

component of the system, and therefore more attention effort should be

paid to mitigate dependence on the utility supply.

Buildings connected the campus-operated turbine generator, if

connected in proper configuration with the normal utility available

through a separate path, is more reliable than buildings that rely on the

utility power alone. Many of the recommendations involve moving more

critical buildings to the turbine, and less critical buildings off.

The turbine, while more reliable than the utility, is not the most reliable

system available that can provide power to any given building. One of




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the main reasons for this is the shared dependency that both the utility

and the turbine rely on a utility gas supply. If the gas supply fails, both

sources of power are lost.

The most reliable electrical system that can be provided to a building is

one that involves an on-site (local) standby diesel generator, while it is

recognized that diesel generators are not preferred on campus. Most

critical buildings, such as data centers and research buildings, should

have local standby diesel generators.

Electrical systems should eliminate single-points of failure as much as

practical, and focus on the points that would have the most impact. The

most prominent example of a single-point of failure at NMSU is the one

main substation switchgear at Tortugas, failure of which would cause a

campus-wide and long-lasting outage (except for the buildings connected

to the turbine). The remedy for this, and one of highest priority, is to

establish a redundant lineup of switchgear with a feed from a new EPE

substation located near Tortugus. For this to occur, EPE requires a

commitment from NMSU for the land to build the substation prior to the

end of 2014 or they will look elsewhere for a substation, according to

EPE.

Other results of the reliability analysis are included herein, all of which were

used in consideration of making the recommendations.

Recommendations: Given the input from NMSU personnel, the information from the

field investigation/data acquisition phase, and the results of the reliability analysis,

recommendations are made along with associated costs for evaluation and

prioritization. While a first attempt is made in listing in order of priority, it is recognized

that discussion and input is still needed to establish the final prioritization.

Recommendations and costs are summarized in the table below:




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NEW MEXICO STATE UNIVERSITY

SITE ELECTRICAL INFRASTRUCTURE MASTER PLAN

COST SUMMARY OF RECOMMENDATIONS

No. Description Costs

1a Create 25 kV Circuits from the Turbine, on Music and Walden

Circuits

$439,000

1b Convert Music to 25 kV and connect to Circuit 6. $182,000

1c Convert Chemistry 96 to 25 kV and connect to Circuit

4/Turbine

$417,000

Subtotal, Chemistry to Turbine $1,038,000

1d Convert Food Court and Library to 25 kV and Connect to

Circuit 5.

$689,000

1e Convert Speech to 25 kV and Connect to Circuit 5. $139,000

1f Convert Hadley, Dove and Guthrie to 25 kV and Connect to

Circuit 5.

$453,000

1g Convert Kent Hall to 25 kV and Connect to Circuit 5. $284,000

1h Convert Williams Art, Annex and Business Admin to 25 kV and

Connect to Circuit 5.

$645,000

1i Convert Jacobs and Hardman to 25 kV and Connect to Circuit

3.

$426,000

1j Connect Corbett to Circuit 4 / Turbine $489,000

Subtotal, Corbett to Turbine $3,125,000

1k Convert Astronomy/Research, Branson Hall, and Young Hall

to 25 kV and connect to Circuit 3.

$466,000

1l Convert Goddard Hall and Thomas & Brown to 25 kV and

connect to Circuit 6

$487,000

1m Convert Foster Hall to 25 kV and connect to Circuit 6. $388,000

1n Convert Walden Hall to 25 kV and connect to Circuit 6 and

back up to Circuit 3, then Connect Milton to Turbine.

$324,000

Subtotal, Milton to Turbine $1,665,000

1o Convert Tejada House to 25 kV and connect to Circuit 6. $176,000

1p Convert Herdsman House to 25 kV and connect to Circuit 6. $100,500

Subtotal, Complete Turbine Circuit Changes $5,828,000

2 Convert Computer Center to 25 kV and add Auto-Transfer

Switch.

$453,000

2

Alt

Alternate: Add local standby diesel generator to backup

computer center.




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NEW MEXICO STATE UNIVERSITY

SITE ELECTRICAL INFRASTRUCTURE MASTER PLAN

COST SUMMARY OF RECOMMENDATIONS

3 Add new switchgear lineup at Tortugas in association with

new EPE substation; separate circuits between switchgear for

redundancy. (Does not include EPE Costs)

$1,401,000

4a New duct banks from Tortugas - Phase 1 $2,470,000

4b New duct banks from Tortugas - Phase 2 $1,820,000

Subtotal, New Duct Banks $4,290,000

5 Computer Model - fault current, arc flash and coordination

study

$80,000

6 Generator for Well Pumps #10 and #17 $426,000

7a Convert buildings near Jett and Engineering complex from 5

kV to 25 kV.

$1,912,500

7b Convert buildings near the football stadium and golf course,

and other remote areas NE of campus from 5kV to 25kV.

$3,367,900

7c Convert the residence hall buildings on the North portion of

campus that are still on 5 kV to 25 kV.

$2,226,500

7d Convert the Regents Row and Activities buildings near the

center of campus from 5 kV to 25 kV.

$1,797,500

7e Convert the Agricultural buildings group at the West end of

campus from 5 kV to 25 kV.

$1,607,500

7f Convert the Facilities and surrounding buildings near the

South portion of campus from 5 kV to 25 kV.

$2,074,500

7g Convert Circuit 2 SE Campus Buildings from 5 kV equipment

to 25 kV

$2,249,500

7h Convert the Biology Annex Building from 5 kV system to 25

kV.

$246,000

Subtotal, Remaining Campus Conversion from 5 kV to 25 kV $15,481,900

Grand Total, Recommendations: $28,236,400




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Conclusion

Like many other Universities NMSU is struggling with an infrastructure which was

designed for a world where reliable power systems were much less critical and where

the consequences of failure were to repair or replace the failed components.. Today,

the consequences of failure can be several orders of magnitude greater than the cost of

repair because a failure of a relatively inexpensive component can cause costly losses.

To resolve this problem, the infrastructure requires a higher level of redundancy and

maintenance support than was necessary for the traditional classroom environment. In

order to be a university that competes with others across the country, NMSU will need

to step up to these challenges or suffer outages which could pose significant losses to

the University in the future.

END OF CHAPTER 1

EXECUTIVE SUMMARY

Chapter 2

Introduction




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New Mexico State UniversitySite Electrical Infrastructure Master Plan

Chapter 2 - IntroductionAugust 27, 2014



Chapter 2 - Introduction August 27, 2014

Page 2-1

II. INTRODUCTION

A. New Mexico State University, Background:

New Mexico State University (NMSU) is based in Las Cruces and serves the

higher education needs of the states diverse population. NMSUs focus is

teaching, research and service at undergraduate and graduate levels and is a

NASA Special Grant College and Hispanic-serving institution. The University

supports the following colleges: Agricultural, Consumer and Environmental

Sciences, Arts and Sciences, Business, Education, Engineering, Health and Social

Services, and Honors. With a designation as a land-grant institution, NMSU

provides research opportunities with a focus on agricultural sciences as well as

life sciences, computer science and computer and electrical engineering, space

science and aerospace, and sustainability (including energy, environment and

water).

Through its community college campuses and other education centers and

research facilities, NMSU maintains a presence throughout the entire State of

New Mexico. NMSU Community Colleges and cooperative extension facilities

offer academic, vocational/technical and continuing education programs

throughout the state.

Mission Statement

New Mexico State University is the state's land-grant university, serving the

educational needs of New Mexico's diverse population through comprehensive

programs of education, research, extension education, and public service.

New Mexico Is Our Campus

With the Las Cruces campus as the universitys base and a motto that New

Mexico is our campus NMSU has an educational presence in every county in the

state including at the four NMSU Community Colleges, which provide academic,

vocational, continuing education programs.

NMSU also maintains a variety of cooperative extension, distance education and

research facilities allowing the university to reach remote locations throughout

New Mexico.

Las Cruces Campus

NMSUs main campus is located in Las Cruces, New Mexico (pop. 101,324). As of

2013, the Las Cruces campus had 16,765 full- and part-time enrolled students,

1,173 faculty and 2,812 staff comprising a broadly diverse ethnic makeup and a




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variety of backgrounds. The Las Cruces campus offers a broad array of degrees,

including 89 Bachelors Degrees, 56 Masters Degrees and 24 Doctoral Degrees.

History

Founded in 1888 as Las Cruces College and the following year established as the

land-grant Agricultural College and Experiment Station by the Territorial

Legislature, NMSU officially opened on January 21, 1890. The college soon

became known as the New Mexico College of Agriculture and Mechanic Arts and

was the first degree-granting institution in the Territory. The special mission of

land-grant institutions (Under the Morrill Act) has been to provide a liberal and

practical education for students and to provide research, extension education,

and public service programs. The college served these academic and research

functions throughout the state as NMSU does today.

New Mexico College of Agriculture and Mechanic Arts became New Mexico State

University in 1960. NMSU continues to maintain excellence in those programs

typically associated with land-grant universities as it has also become a

comprehensive doctoral-level university with a wide variety of programs

including: Agricultural, Consumer and Environmental Sciences, Arts and Sciences,

Business, Education, Engineering, and Health and Social Services.

2011 Power Outage

In February of 2011, Las Cruces, NM experienced unusually cold weather that

caused failures in the local electrical utility (EPE) power grid that depended on

gas-powered turbines at their power plant. NMSU during that time was relying

on the limited capacity of its gas-powered turbine generator and had to cut load

back to a minimum that resulted discontinuation of classes and other campus

operations. This outage lasted for 3 4 days until temperatures rose, and was a

convincing reminder of the dependency a campus has on reliable power for

every day operations, and the need to develop an infrastructure to endure such

an outage.

B. Need for an Electrical Infrastructure Master Plan:

In February 2013 NMSU issued a Request for Proposal to obtain engineering

services to provide a Site Electrical Infrastructure Master Plan. Some of the

driving factors behind the request and need for a master plan included the

following:




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1. Reliability: The need for higher reliability in the electrical infrastructure

that serves buildings on campus, especially the more critical buildings involving

research, data centers, and important student services. The 2011 outage in Las

Cruces that crippled the campus for days emphasized the need for reliable

power. Establishing a plan that could mitigate such an event in the future is of

highest priority.

2. Use of campus turbine generator for critical buildings: Related to

reliability, the campus sees its turbine as a reliable source of power, and

therefore, more critical buildings should be moved to the turbine and less critical

buildings moved off. The Master Plan should review and validate this approach,

if it does indeed improve reliability, and present a phased plan to implement this

strategy.

3. Conversion of distribution system to 25 kV: The campus has two

distribution voltages, 5 kV and 25 kV. Besides the added complexity to operate

and maintain two different voltages, the 5 kV system is mostly very old and the

campus desires to migrate towards an all-25 kV system, eventually.

4. Old and failing components: Some parts of the existing electrical system

are 50+ years old and beyond expected life. Rather than respond to failures as

they occur, a master plan, together with proper funding, could proactively

replace components prior to failure, and do so in a manner that fits long term

growth and future plans.

5. Address immediate projects: Projects being planned or under

construction need to be connected into the electrical system that coordinates

with the big picture plan for the campus infrastructure. The reliability and

simplicity of campus distribution systems often degrade over time as the

electrical distribution system is modified only a piece at a time and in a manner

that has the least cost impact for a particular building or project whose goals are

not to develop a more robust electrical infrastructure. Having a plan already in

place for known future buildings sets the path to move forward. Projects in

planning phase or construction at the time this Master Plan included renovations

at Hershel-Zohn, Jacobs/Hardman, Corbett Center and Institute for Public Policy.

6. Growth and Flexibility: As the university continues to grow and future

projects change the landscape of the campus, the electrical system must be set

up and in place to accommodate the changes and growth. In anticipation of this,

the Master Plan should recommend system improvements and additions that




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will set a clear path for connecting future project to the electrical infrastructure,

keeping with the plans goals in an organized approach.

7. Review of previous master plans: Two plans in particular were to be

reviewed in the development of this Master Plan: The 2006 Physical Master

Plan, and the 2009 Utility Master Plan.

C. Project Approach: In August, 2013 Bohannan Huston and Spectrum Engineers

was awarded the services for the Site Electrical Infrastructure Master Plan and

given notice to proceed. Efforts began shortly thereafter with the following

approach:

1. Design Meetings / Charrettes: The most important members of any

master planning effort are the owners representatives and end users

themselves, who have every day, first-hand knowledge of their facility, and who

have to eventually live with, operate and maintain the results. For this purpose,

several design meetings or charrettes were held to obtain valuable input of the

ideas and knowledge of the NMSU personnel who have the most knowledge and

interest in the electrical system. A charrette is an intensive planning session

where users, designers and others collaborate on a vision for development. It

provides a forum for ideas and offers the unique advantage of giving immediate

feedback to the designers. More importantly, it allows everyone who

participates to be a mutual author of the plan. Much of the content of this

Master Plan is a direct result from these charrettes. Notes of the various

meetings and charrettes are included in the Appendix of this report.

2. Field Investigation / Data Acquisition: In order to better understand the

system, and to identify potential upgrades or corrections to meet the goals of

the master plan, an intensive field investigation effort was performed during the

months of September and October (2013) in order to obtain information and

gather data about the existing electrical distribution system. This included a

review of all medium-voltage transformers and switches. Nameplate data and

photos were documented, organized and summarized. The results of the effort

are included in the Appendix and were a valuable resource in developing the

final recommendations of this master plan. The inventory of field data should

also prove to be a valuable asset to the campus for system maintenance moving

forward.




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3. Reliability Analysis: Rather than rely on gut feel, differing opinions or

preferences, an analytical approach was used to calculate the relative reliability

of different system options. The approach is based on statistical probability

calculations as set forth in the IEEE Standard 493-2007, IEEE Recommended

Practice for the Design of Reliable Industrial and Commercial Power Systems,

otherwise known as The Gold Book. This method provides information that

allows better informed choices based on level of reliability (increase or decrease)

that an idea might have. For example, a recommendation may appear to be

good and come with a high cost, however, a reliability analysis may prove that it

has little or no improvement on overall system reliability and therefore would

not be a good choice to expend available funds.

4. Recommendations: Based on input from NMSU, field investigation data,

and the reliability analysis, recommendations are made for system modifications

and improvements. Costs are associated with each recommendation and

presented in several phases so that work may continue at a pace that is

determined by available funding. An attempt is made to prioritize the

recommendations; however, there will undoubtedly be adjustments in the order

or priority by which projects are accomplished.

D. Exclusions: It may be important to mention items that are not included in this

Master Plan, or areas that were not part of the main focus even though they may

be part of the electrical infrastructure. These include:

1. As-Built drawings of the existing system: while extensive field

investigation was performed, the goal was not to perform an exhaustive and

comprehensive effort in order to develop complete drawings showing accurate

as-built conditions of the existing system. Rather, important information was

obtained relevant to the recommendations made herein.

2. Duct bank capacity and conditions: Information regarding each duct bank

segment relating to condition, available spares, usability, etc. was not obtained

during the master planning effort. Where new feeders are required to

implement recommendations, it is assumed that existing duct banks cannot be

reused and new will be required.

3. Cable condition: 5 kV and 25 kV cable sizes were observed at the

termination points, but no assessment was made as to the age and condition,

and therefore no recommendations are made to replace failing cables. The




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campus has an on-going effort to replace old cables as part of normal

maintenance routing, so effort in the master plan was not expended on this

topic.

4. Load studies: Detailed load studies and projections were not performed.

Load information was obtained from available meter data currently installed and

available on campus, and from rough estimates based on assumed watts/SF of

certain building types where meter data was not available. As for load

projections, neither accurate nor consistent information was available on which

to base dependable load projections. Future building projects are unpredictable

due to unknowns of State funds, and previous master plans have overestimated

projected loads compared to actual loads by a substantial amount. Loads have in

fact decreased since 2006. However, this Master Plan does take into account

the fact that the campus and its loads will grow, and presents a plan for

managed and sensible growth in the electrical infrastructure.

5. Cogeneration: This Master Plan does not evaluate the need for

additional campus cogeneration capacity for the purposes of an economical

power source.

6. Detailed Design: Recommendations and ideas are prepared and

presented sufficient to communicate the idea with enough description to obtain

rough order of magnitude costs, which will allow the campus to make decisions

based on need and available funding as to which projects to implement. High-

level sketches and ideas are provided, and are not to be considered to be a

design, even at a schematic level. The design effort is reserved for the various

projects when they are selected for implementation.

E. Acknowledgements Many thanks to the following individuals who have

contributed to this effort:

1. NMSU Team:

a) Dale Harrell Lead Facilities Engineer

b) Glen Haubold Associate Vice President for Facilities

c) John Shen MEP Director

d) Alton Looney Project Manager

e) Lucio Garcia Project Manager

f) Pat Chavez Energy Manager

g) David Coon Electrician

h) Mike Luchau Electrician




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2. BHI Team:

a) Matt Thompson, Project Manager

b) Evan Fleischer, Engineer Intern

3. Spectrum Team:

a) David Wesemann, Principal Project Manager

b) Patrick Garey, Principal

c) Jim Morris, Engineer Intern

d) Chris Fry, Engineer Intern

END OF CHAPTER 2

Chapter 3

Existing System




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New Mexico State UniversitySite Electrical Infrastructure Master Plan

Chapter 3 - Existing SystemAugust 29, 2014



Chapter 3 Existing System August 29, 2014

Page 3-1

III. EXISTING SYSTEM

A. Definition of terms and abbreviations:

1. 5 kV for NMSU a 5 kV electrical system is an abbreviation for the 4,160

Volt electrical system on campus.

2. 25 kV for NMSU a 25 kV electrical system is an abbreviation for the

23,900 Volt electrical system on campus.

3. Circuit The term circuit is used to designate 5 kV or 25 kV feeders

within the campus that originate from distribution switchgear at the point where

NMSU receives power from EPEC. Presently there are 7 circuits on campus.

4. EPEC, or EPE El Paso Electric Company, the serving utility for NMSU.

5. Feeder This term is used to designate the main supply source and

conductors from the utility (EPE) to the campus.

6. High Voltage (HV) voltages above 35 kV.

7. kiloWatts (kW) thousand Watts. Watt is a unit of power.

8. kiloVolts (kV) thousand Volts. Volt is a unit for potential difference.

9. kiloVoltAmpere (kVA) thousand Volt-Amperes. Volt-Ampere is a unit

for apparent power.

10. Medium Voltage (MV) voltages in the range of 1 kV to 35 kV.

11. megaWatts (MW) million Watts.

12. SF6 sulfur hexafluoride, an electrical insulator and used in the

manufacturer of electrical equipment.

13. Substation part of an electrical power distribution system and may

contain one or more of following: transformers for voltage conversion, circuit

breakers and switches to protect and/or disconnect one or more sources from

the distribution system. Typically on NMSU campus, the term substation is a

distribution switchgear with or without 25 kV 5 kV voltage conversion. There

are no substations on NMSU campus that contain high-voltage to medium-

voltage conversion.

B. Field Investigation: Much of the information in this report was obtained during

an extensive field investigation effort that took place during a 2-month period,

Sept. Oct. 2013. Other information was obtained directly from NMSU




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engineering and maintenance staff who have direct and constant knowledge and

experience with the campus electrical distribution system.

C. Serving Utility and Campus Substations: New Mexico State University is served

by El Paso Electric Company (EPE). During the year ending December 2012, EPEs

energy sources consisted of approximately 46% nuclear fuel, 32% natural gas, 6%

coal, 16% purchase power and less than 1% generated by wind turbines. The

shortage of gas supply during the cold weather in February 2011 is believed to

be the root cause of the resulting power outages. EPE serves NMSU campus

through two separate campus substations, Tortugus and Geothermal.

1. The Tortugas Substation is a 25 kV feed from EPE and is located in the

southeast portion of the campus, west of Interstate 25. It feeds the majority of

the main campus. It serves campus loads both directly with 25 kV as well as 5 kV

through multiple 25-5kV campus transformers. Campus circuits 1 6 originate

from Tortugus.

2. The Geothermal Substation is also 25 kV feed from EPE, which is

immediately stepped down to 5 kV at the substation prior to being distributed to

campus facilities. The Geothermal Substation is located on the east side of

Interstate 25 and feeds the football stadium and the NMSU buildings and

facilities east of Interstate 25. Campus circuit 7 originates from Geothermal.

D. Cogeneration:

1. NMSU has a cogeneration plant consisting of a single 5 MW natural gas-

driven turbine that generates approximately 4.8 MW of capacity. The

cogeneration plant feeds circuits 3 and 4 (described below) and is providing

redundancy for the EPE Tortugas Substation loads connected to these circuits.

The cogeneration plant is currently operating at 5 kV and primarily serving loads

at this voltage.

E. 25 kV and 5 kV systems:

1. The NMSU campus medium voltage distribution currently contains two

different voltages, 5 kV and 25 kV. The legacy campus medium voltage

distribution is 5 kV. Most of the housing and newer buildings/facilities and

remodel buildings/facilities are utilizing the 25 kV voltage.




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2. 25 kV 5 kV, Bi-Directional Transformers: As part of the network of 5 kV

and 25 kV systems on campus are transformers that convert between the two

voltages. With few exceptions, these transformers are wye-wye configured and

operate in both directions, depending on the current circuit and switching

arrangement needed at any given time. Many of the transformers do not have

overcurrent protection on one or both sides. In addition, the bi-directional

operation of the transformers creates some confusion regarding NEC

requirements for transformer overcurrent protection for primary (supply) and

secondary (load) sides. This will be dealt with in more detail in the

recommendations portion of the report.

3. The long term plan of the campus, and one of the main purposes of this

report, is to phase out or convert the existing 5 kV systems to the 25 kV system.

The 5 kV system on campus has several disadvantages, which include:

a) Extra cost required for the 5 kV 25 kV transformers.

b) Additional space required for the transformers.

c) Wasted energy through the 5 kV 25 kV transformation, which is

costing the campus 24 hours/day x 365 days/year, even at no load.

d) Code requirements for bi-directional transformer overcurrent

protection are unclear as noted above.

e) For closed-transition switching, extra care and precaution must be

in place due to potential of mismatched transformers that might operate

in parallel. This includes a possibility of impedance mismatching and

phase shifting.

f) Limited capacity of 5 kV cabling and equipment, carrying less than

20% of the load compared to 25 kV distribution using the same cable or

bus size.

g) Generally, the 5 kV system on campus is the older portion of the

distribution system and there is a concern of maintenance and failures

given the age and condition of the cabling and equipment.

F. Circuits:

1. There are currently seven medium voltage circuits that provide power for

the campus, 6 from EPEC Tortugus substation and 1 from the EPEC Geothermal

substation. They are described briefly below, and can also be seen on the




Page 3-4

campus circuit maps and one-lines included in this report (refer to drawings in

Chapter 6):

a) Circuit 1 is fed from the EPEC Tortugas substation. For the most

part it feeds the married student housing in the southwest portion of the

campus triangle and is the only circuit that operates entirely on the 25 kV

system (under normal operating conditions) directly from the substation.

This circuit is generally loop configured, but there are radial feeds with

several transformers that branch off of the loop which increases

probability for longer outages. It can be backed up by circuits 4 or 6

through normally-open switches at different locations on the loop. Most

transformers on this circuit are pad-mounted, single phase, 167 kVA at

13.8 kV (line-to-neutral connections on the 13.8/23.9 voltage). Because

of this, it is important to maintain the wye-configured distribution on this

and any circuit that can be used as backup for this circuit.

b) Circuit 2 is fed from the EPEC Tortugas substation and feeds the

southeast section of the campus triangle, including Breland Hall, Student

Health Center, Activity Center, Greek Houses and several others. It has

both 25 kV and 5 kV circuits through two different bi-direction

transformers. It is generally loop configured, but has some radial dead

ends including the portion feeding the fire station. This circuit can be

backed up by Circuits 5 and 7.

c) Circuit 3 is fed from the EPEC Tortugas substation and can be

backed up directly from the cogeneration plant. It serves mainly the

central utility plant and buildings located in the center of campus through

the Non-Essential switchgear. There is a mixture of 5 kV and 25 kV

feeders through five bi-directional transformers. Some of the load

transformers that Circuit 3 feeds include the Computer Center, Physical

Science Hall, Branson Hall, and the new library. Besides the possibility for

cogeneration back up, portions of this circuits can also be fed by Circuits

4 (multiple ties), 5, and 6.

d) Circuit 4 is fed from the Tortugas substation and connects directly

into the cogeneration plant Essential Switchgear through two bi-

directional, paralleled 2500 kVA transformers. There are no 25 kV loads

on this circuit (under normal operation) as all the loads are fed from the 5




Page 3-5

kV cogeneration switchgear. Similar to Circuit 3, it serves mainly the

central utility plant and buildings located in the center of campus. Circuit

4 can be backed up by circuits 1 and 3 (multiple ties).

e) Circuit 5 is fed from the Tortugas substation and feeds mainly the

northeast section of the campus triangle, including the Pan American

Center, Chamisa Village, Corbett Hall and Garcia Hall. There is a mixture

of 5 kV and 25 kV feeders through two bi-directional transformers.

Portions of it can be fed by Circuits 2, 3 and 6.

f) Circuit 6 is fed from the Tortugas substation and feeds the

northwest portion of campus. Most of the load transformers are on the

25 kV portion of the circuit, however, there are some portions on 5 kV

through two bi-directional transformers. This circuit can also be fed by

Circuits 1, 4 and 5.

g) Circuit 7 is the only circuit fed from the EPEC Geothermal

substation. While this is a very reliable feeder from EPEC (the hospital is

also on this same feeder), it has limited capacity for any growth on

campus. All loads are connected at 5 kV through a 2000 kVA 25-5 kV

step-down transformer. This circuit feeds the eastern-most (off-triangle)

portion of campus where the main athletic venues are located, including

the football stadium and the golf course. The Presidents Residence is

also on this circuit. It can be backed up by Circuit 2 through the

Locust/Stewart oil switch, which is an older switch and should be

considered for replacement given that it is the only means of backup for

this circuit.

2. Back-up Circuits: As described above, each circuit at NMSU has the

capability of being fed by at least one other circuit as a redundant source, and in

some cases multiple back-up circuits exist. The chart below summarizes all

switching possibilities between circuits on campus:




Page 3-6

NMSU - Circuit Switching Possibilities

ckt 1 2 3 4 5 6 7 CG

1 X X

2 X X X

3 X 5X X X

4 X 5X X X X

5 X X X

6 X X X X

7 X

CG X X

X= Circuits that can directly switch to the other

Prefix number indicates quantity if more than 1

CG= Cogen Plant

3. Closed-Transition Switching: Presently, NMSU prefers to perform closed-

transition switching to minimize the power-bumps caused by open-transition

switching. Due to the multiple power sources on campus (two separate utility

feeds and cogeneration), including several bi-directional transformers, it is

critical that sources are matched and synchronized when performing the closed-

transition switch operations.

G. Load and Capacity of the Electrical Distribution System: The present total

campus load is between 12MW 13 MW (not including contribution from the

cogeneration unit), but is anticipated to decrease to 10MW 11MW by July of 2014 due

to current ESCO projects that will reduce peak demand and energy consumption.

Beyond this, it is difficult to predict campus load growth due to the unknowns of

available of funding from year to year and ongoing changes in plans for new buildings.

To illustrate this, a previous campus planning report put the campus load at around 16

MW in 2006 and estimated that it would reach 20 MW by the end of 2014, which is

almost double the actual usage. Nonetheless, it is still best practice to consider future

load growth in master planning study.

1. Campus / overall

a) The peak demand for circuits 1 through 6 (Tortugus substation) is

about 13,500 kW on Sept. 17, 2013 (this was obtained by taking the peak

of 9,000 kW on this date then adding the 4,500 kW contribution from the




Page 3-7

turbine. This is 15 MVA at 0.9 PF which is 362 amps. The maximum

capacity available on one feeder from an EPE source feeder is

approximately 465A at 23.9 kW, so the Tortugus feeder is about 78% of

its capacity, which is approaching the limit for consideration of an

additional power source (this condition occurs when the cogeneration

unit fails or is down for maintenance). EPE has also indicated that it has

difficulty maintaining capacity to the campus on the preferred Tortugus

feeder when the turbine is shut down. One other concern is that the

alternate source from EPEC to Tortugus is limited to 5 MW and cannot

supply the campus if turbine is down and the preferred source fails. The

loads and capacities of this substation are summarized in the table

below:

b) The cogeneration turbine peaked at close to 5,000 kW on January

4, 2013 but normally runs between 4,000 kW - 4,500 kW. The substation

and circuit loads that are given in this report are as if the turbine is not

running or contributing to the capacity. In addition to the energy

benefits of running the turbine, it is also considered to be a reliable

alternate source of power for the more critical buildings on campus. It is

therefore important to manage the buildings and loads that are

connected to the turbine such that it can supply power to the critical

Tortugas Substation Total Load Summary

Estimated Peak Real Power (MW) September 17,

2013 (Excluding contribution of turbine) 13.5 MW

Apparent Power(MVA) and Amperage (A)

@ 23.9 kV and estimated 0.9 PF 15 MVA / 362 A

Gross Square Footage (SF) of Buildings on Campus

(Excludes buildings on feeder 7) 5,352,986 SF

Campus Load Density (VA/SF) 2.8 VA/SF

EPE Capacity (MVA and A) @ 23.9 kVA 19 MVA / 465 A

Percent of Available EPEC Feeder 78%




Page 3-8

buildings in the event of a failure of power from EPE. This will be

discussed further in the recommendations portion of this study.

2. 25 kV Circuits: Each campus circuit on the 25 kV system is typically rated

at 200A, or about 8.3 MVA at 25 kV. Since circuits can backup each other in case

of failure, no circuit should be loaded to more than 40%, or about 3.3 MVA

(80A), to allow the feeder to assume the entire load of another and still be no

more than 80% capacity. The recorded peak kW demand with corresponding

date for each circuit is listed below (note that power factor is not recorded on

these circuits so the power factor is estimated at 0.9):

Tortugus Circuits

a) Circuit 1: 900 kW on September 9, 2013, but peaked to 1,348 kW

on August 9, 2013 the same day Circuit 2 & 5 were at 0 kW so the

abnormally high peak is most likely due to switching operations.

b) Circuit 2: 3,273 kW on June 6, 2013.

c) Circuit 3: 2400 kW on July 25, 2013, but peaked to 2,766 kW on

October 3, 2013 which is most likely when part of Circuit 2 was switched

to this circuit.

d) Circuit 4: 4,050 kW on June 11, 2013 (this is with the assumption

that the Cogen is putting out 4,500 kW).

e) Circuit 5: 2,551 kW on November 7, 2013.

f) Circuit 6: 2,700 kW on June 13, 2013, but peaked to 3,215 kW on

December 4, 2013 when power from Circuit 3 was switched over to this

circuit (this is deduced from the graphs of the demands on each circuit).

Geothermal Circuit

g) Circuit 7: 807 kW on unknown date. The corresponding EPE

feeder into Geothermal substation has limited capacity for NMSU and no

additional load should be added to this circuit.




Page 3-9

Note that most circuits are at or beyond the goal of keeping load to 40% or less

of capacity to allow for switching, however, the total of these circuits exceeds

the total demand of the Tortugus substation. This is due to variation of when

peak demands occur, and also potential switching operations that could have

caused the recorded peak value per circuit to be greater than normal operations.

The state of the switches at the time of the peak is not recorded and correlated

with the measured peaks.

3. 5 kV Circuits Circuits operating at 5 kV are derived from any one of the

(7) 25 kV circuits on campus through several transformers (most of the bi-

directional as previously discussed), and the circuits that are fed directly from

the 5 kV cogeneration turbine. The 5 kV circuits are not uniquely identified,

Tortugas Substation Circuits

Circuit

No. Serves

Peak

MW

(2013)

MVA

@ 0.9 PF

Amps

@23.9 kV

% Load

@ 8.3 MVA

(100%)

% Load

@ 3.3 MVA

(40%)

1 Buildings located on the Southwest

section of campus (Housing) 0.90 1.00 24.2 12.0% 30.3%

2

Buildings located North, South, and

East of the Intramural fields and

running track.

3.27 3.63 87.8 43.8% 110.1%

3

Central utility plant and buildings

located in the Southern center of

campus.

2.40 2.67 64.4 32.1% 80.8%

4

Central utility plant and buildings

located in the Northern center of

campus; with turbine NOT running.

4.05 4.50 108.7 54.2% 136.4%

5

Buildings located on the Northeast

section of the campus, including the

Northeast campus housing.

2.60 2.89 69.8 34.8% 87.5%

6 Buildings located on the Northwest

section of the campus. 2.70 3.00 72.5 36.1% 90.9%




Page 3-10

other than the number of the 25 kV circuit of which they are a part. For the

most part, there is no separate metering on the 5 kV portions of the circuits so it

is difficult to summarize the loads. The capacity of each 5 kV leg of the system

has an upper limit of 2 MVA based on transformer and cable size, but sometimes

as low as 1 MVA due to smaller transformers and/or reduced overcurrent

protection rating.

H. Equipment and Cabling: During the field investigation phase of this study,

medium-voltage equipment (switches and transformers) were documented and

a complete inventory of that effort is included in Appendix A. The inventory has

label, manufacturer, date of manufacturer, voltage, capacity, location, mounting,

and catalog number. An inventory of cabling was not done, other than noting

sizes at each termination point on the equipment. A summary of the inventory is

indicated below. Refer to the appendix for more detailed information.

1. Switches the campus currently has four types of switches, oil, air, SF6,

and solid dielectric. Most new and replacement medium voltage switches are

solid dielectric, which is the current NMSU standard.

a) Oil quantity 26, most are 25 years or older. These switches will

be recommended for high-priority replacement.

b) Air quantity 22, most were built and installed in the 1990s.

c) SF6 quantity 28, approximately half were built 10 years ago, the

other half were built 20 years ago.

d) Solid Dielectric quantity 11, all were built and installed within

the last 5 years.

2. Transformers- the campus currently has about 239 transformers,

including those that serve buildings as well as those used for the 25 kV-5 kV bi-

directional conversion. Most of the transformers are oil-filled, but there are

some FR3 liquid filled, and some dry types. Listed below is a range of ages and

the quantities of each. Older oil-filled transformers should be considered for

replacement. All new transformers should be the environmentally-safe and less-

flammable FR3 type.

a) Unknown 29

b) 1960s 6




Page 3-11

c) 1970s 12

d) 1980s 59

e) 1990s 88

f) 2000s 33

g) 2010s 12

3. Cables: The standard cable on NMSU campus for the 25 kV circuits is a 25

kV EPR #4/0 aluminum conductor with 1/3 copper concentric neutral. It has an

ampacity of 200A (in most common duct bank configurations) or about 8.3 MVA.

The standard cable for 5 kV portions of circuits is a #500 kCMIL CU EPR and

concentric neutral, which has an ampacity of about 400A, or 2.9 MVA, however,

the capacity of these circuits are limited to the transformer and overcurrent

protection size as indicated above. Replacement of older cables is an on-going

project at NMSU. The inspection of cables and recommendations to replace

cables is not addressed in this study.

4. Duct Banks: Underground conduit duct banks for the most part are 4 for

both the 25 kV and 5 kV portions of the system. In most cases, multiple circuits

share a common duct bank. This study does not document as-built conditions

of duct banks, in particular, any spares that might be available for future circuits.

I. Emergency and Standby Systems: The campus has central emergency

generation consisting of redundant 300 kW generator sets that are 480V stepped

up to 5 kV, then distributed throughout campus. This system was originally

intended only for code-required emergency loads, such as emergency egress

lighting. It does not have capacity to serve larger standby loads. While the plan

is to maintain it as a central emergency system, the current campus directive is

to provide battery packs for emergency egress lighting in buildings, and not to

grow or add to the 5 kV emergency system. Local generators are not used for

emergency purposes, however, some of the buildings on campus have local

generators due to the larger legally-required standby load requirements (such as

smoke evacuation systems), or the critical nature of a building requiring a local

standby generator. The campus presently considers the cogeneration turbine as

a reliable alternate source of power for critical buildings, and therefore the

buildings normally powered from the turbine do not have backup generators.

Buildings that have a local standby generators are listed below:




Page 3-12

Location/Building BLDG # Owner Type

1. A Mountain NA KRWG/I&G Diesel 350-kW

2. Aggie Stadium 342 Aux Services Diesel 100-kVA

3. Biology Annex Roof 82 I&G NG 20-kW

4. Central Plant North 269 I&G Diesel 300-kW

5. Central Plant South 269 I&G Diesel 300-kW

6. Central Plant Inside 269 I&G Diesel 200 kW

7. Police Department 30 I&G NG 20-kW

8. Skeen Hall 551 I&G Diesel 233-kW

9. Wooten Hall 585 I&G Diesel 150-kW

10. Chemistry 96 BSL 187 I&G NG 35-kW

11. Pan Am Center 284 Aux Services Diesel 750-kW

12. Foster Hall 34 I&G Diesel 250-kW

13. EMF 371 I&G Diesel 45-kW

14. PSL 263 PSL/I&G Diesel 125-kW

15. Satellite Plant 644 I&G Diesel 250-kW

16. Center for the Arts 631 I&G Diesel 250-kW

17. Fire Department 267 I&G Diesel 150-kW

J. Building Types / Categories: There are 468 separate buildings or structures

documented on campus, however, only about 131 are considered to be counted

as significant or important on the main campus. Building and facility types

include: residential, classroom, laboratory/research, agricultural,

office/administrative, performing arts, greenhouses, athletic, shops, student

centers, food service and pump stations. The oldest building was built in 1890,

however, the majority of the buildings have been built after 1950. Appendix C

contains a listing of buildings with pertinent information, such as size, electrical

service and load (if known). One important factor of this study is to prioritize

buildings based on the need for reliable power. Higher priority buildings will be

slated to be placed on the turbine (if not already), while lower priority buildings

will be taken off the turbine to free up the needed capacity. The building priority

list and related discussion is included in Chapter 4, Reliability Analysis.

END OF CHAPTER 3

Chapter 4

Reliability Analysis




Page TC-1

New Mexico State UniversitySite Electrical Infrastructure Master PlanChapter 4 - Reliability Analysis

August 27, 2014



Chapter 4 Reliability Analysis August 27, 2014

Page 4-1

IV. RELIABILITY ANALYSIS

A. General: In making recommendations to improve the NMSU electrical system

reliability, the analytical methods and guidelines as set forth in IEEE Standard

493-2007, IEEE Recommended Practice for the Design of Reliable Industrial and

Commercial Power Systems (also known as The Gold Book) will be followed.

Hereafter, this will be referred to simply as IEEE 497. This section of the report

will provide an overview of the evaluation methods and formulas of IEEE 497 and

how they might apply to the NMSU Campus. Based on the results of the

reliability evaluation, general recommendations are given in this chapter.

Specific recommendations or work action items are provided in the next section,

and they will follow the guidelines discussed in this section along with other

criteria for system improvements.

B. The basis of the IEEE 497 formulas is that each and every component of an

electrical system has a) a failure rate (commonly expressed in failures per year),

and b) an average downtime per failure (usually expressed in hours per failure).

It is not if, but when a component will fail, and how long the failure lasts. When

these criteria are combined using statistical probability theory, the result is total

downtime per year (in hours) at a given point in the system. When multiple

components are combined in series or parallel as determined by the system

configuration, the total downtime at any given point in an electrical system due

to the upstream components can be calculated and expressed in total hours of

downtime per year. Based on the results, changes in components and/or system

configuration can be made to improve the reliability.

1. The following basic formulas are used in the system evaluation for

parallel or series connected components or portions of the system.




Page 4-2

Formulas for Calculating Reliability

For Series-Connected Components

For Parallel-Connected Components

Where:

2. It is important to note that the results of these formulas give expected

forced outages based on age and normal use of equipment. The formulas do not

take into account:

a) Failures due to human error.

b) Failures (planned or unplanned) due to construction activities.

c) Failures due to lack of maintenance.

d) Improper engineering design.

e) Improper operation of equipment.

f) Failures of utility gas supply (important for turbine operation).




Page 4-3

C. Using this approach, the formulas were applied to system configuration types

that are found on the NMSU campus. The following system types were

evaluated. The evaluation is done from the serving utility down to the secondary

side of a building transformer up to and including the first main overcurrent

device. Basic diagrams for each are included at the end of this section.

1. Simple Radial: One utility serving one building through a medium-voltage

system consisting of distribution, cabling, switches and transformer. It is not

looped back to the source. For comparison, this is the baseline system and all

others are compared to the reliability of this one.

2. Simple Radial with multiple buildings: same as above, except multiple

buildings are on the same feeder with no loop back to source. This case is not

found on NMSU, but is presented to illustrate degrading reliability if this should

occur.

3. Loop to Same Source: The feeder is looped back and connected to the

same source and bus from where it originated. This is a typical configuration on

NMSU.

4. Loop to Same Source with Multiple Switches/Terminations: This is more

common and is based on an average number of switches before a feeder reaches

a typical building.

5. Loop to Same Source with 25 kV-5 kV Transformers: Represents a feeder

that services both 25 kV and 5 kV loads through the bi-directional transformers,

common on NMSU campus.

6. Loop to Same Source, with Local backup Generator: Same as above with

local generator added. The comparative results apply only to loads connected to

the generator (whether it be the entire building, or only selected loads). Few

buildings on campus have local backup generators. This is analyzed to show that

buildings with local generators are the most reliable configuration.

7. Loop to Separate Utility: This configuration is not found on campus, with

one limited exception (Circuit 7 from Geothermal connecting to Circuit 2 from

Tortugus). Results show that this would have a noticeable increase in reliability

throughout campus, and is the basis for one of the recommendations discussed

in the next section. This similar to above, this is calculated with and without a

local generator.




Page 4-4

8. Loop to Separate Utility with Auto Switch: Same as above, except the

switch from one feeder to another is done via and automatic transfer switch on

the medium-voltage side. All previous configurations rely on a manual transfer,

which takes time for personnel to assess the problem and make the switch. The

auto switch as expected can significantly increase the reliability for more critical

buildings.

9. Loop to Cogeneration (Turbine): The feeder loop begins at the utility

switchgear and ends up at a separate turbine that has no other connection or

interaction with the Utility. This configuration is calculated with manual and

auto switch schemes, as well as availability of local backup generator.

10. Loop to Cogeneration (Turbine) typical of NMSU: This scenario takes into

account the interaction that the utility had with the cogeneration unit at NMSU,

in that the turbine is backed up by Circuit #4, and any building on this system can

be switched to any one of a number of other circuits separate from the turbine.

11. Secondary Selective: A few different configurations of a secondary

selective system are explored, including manual and auto-switch schemes.

NMSU does not have any secondary selective systems on campus, but is shown

for comparison and what might be possible for critical buildings. Not counting

the contribution of a local generator, the secondary selective system is the most

reliable of all the above.

D. Reliability Data: As previously mentioned, each component of the electrical

system has a failure rate ( ) and an average downtime per failure ( r ) that is used in

the calculations. This data is taken from IEEE 497, and the values used for the NMSU

campus system are listed below, in order of least reliable, or most hours of downtime

per year, to most reliable (the reasons for sorting in this order is discussed below):




Page 4-5

RELIABILITY DATA (from IEEE 497)

Ranking of Components found on NMSU Campus -

Least Reliable to Most Reliable (from IEEE 497)

Total

Failures

per Year

r,

hours

down-

time per

failure

.r Total Hrs.

down-

time

per Year

Utility MV Source from EPE 1.9560 1.3200 2.5819

Utility Double Circuit, loss of one and other is OK 1.6440 1.0000 1.6440

Transformer (Spare available) 0.0108 48.0000 0.5184

Utility Double Circuit, loss of both circuits 0.3120 0.5200 0.1622

480V Switchgear Bare Bus 0.0095 7.2900 0.0692

MV Switchgear Bare Bus 0.0179 2.2700 0.0407

MV Cable, in conduit below ground 0.0024 15.7000 0.0371

MV Switch 0.0063 4.2000 0.0264

Control Panel, Generator 0.0111 2.1100 0.0234

Gas Turbine Generator 0.0353 0.2720 0.0096

Primary Protection and Control System 0.0006 5.0000 0.0030

480V Feeder Circuit Breaker 0.0002 6.0000 0.0013

MV Circuit Breaker (spare available) 0.0019 0.5000 0.0009

480V Cable in conduit above ground 0.0001 8.0000 0.0006

480V metal-clad circuit breakers (5) 0.000095 4.0000 0.00038

MV Cable Terminations 0.0004 0.7500 0.0003

480V Cable Terminations 0.0004 0.7500 0.0003

480V Main Circuit Breaker 0.0027 0.0108 0.00003

E. Reliability Calculations Summary: Results of the reliability calculations for the

various system types listed above are summarized in the table below. The detailed

calculations together with the representative diagrams are included in Appendix D. The

table summarizes each system and compares each to the baseline, or simple radial

system. Failures per year and total hours of downtime per year are given, along with a

comparison value to indicate the increase (or decrease) in reliability for the different

system types (shown in far right-hand column). Numbers greater than 1 are more

reliable than the baseline system, and the greater the value, the more reliable a system

is. It can be seen that some systems have only a marginal improved reliability over the

simple radial system, while others are many times more reliable. Further discussion and

analysis follows below.




Page 4-6

Sheet #

COMPARISON SUMMARY OF SYSTEM TYPES

Power Distribution System Type

Total

Failures

per

Year

.r Total

Hrs.

Down-

Time/Yr

Comparison

to Baseline (Bigger #'s

are Better)

Simple Radial (Baseline) 2.03 3.36 1.00

ESR-1 Simple Radial (Base System) 2.03 3.36 1.00

7 Building Simple Radial (Base System) 2.09 3.56 0.94

ESR-2 Loop Back to Same Source (Primary Selective) 2.03 3.28 1.03

ESR-3 Loop Back to Same Source-Multiple Switches/Terminations 2.04 3.29 1.02

ESR-3T Loop Back to Same Source with 5kV - 25kV transformers 2.05 3.30 1.02

ESR-3G-NB Loop Back to Same Source with Generator w/o ATS bypass 0.11 0.35 9.57

ESR-3G-B Loop Back to Same Source with Generator w/ ATS-bypass 0.11 0.18 18.96

ESR-4 Loop Back to Separate Utility 2.04 2.49 1.35

ESR-4 Loop Back to Separate Utility Auto Switch 2.04 0.79 4.23

ESR-4G Loop Back to Separate Utility with Generator 0.11 0.66 5.12

ESR-5 Loop Back to Turbine 0.12 0.72 4.68

ESR-5 Loop Back to Turbine Auto Switch 0.12 0.63 5.31

ESR-5G Loop Back to Turbine with Local Generator, ATS w/o bypass 0.05 0.34 9.77

ESR-5B Loop Back to Turbine Typical of NMSU 0.09 0.69 4.87

ESR-6 Secondary Selective - Manual Switch 2.04 1.96 1.72

ESR-6 Secondary Selective - Auto Switch 2.04 0.25 13.71

Note: Forced outages due to equipment only. Does not take into

account:

Planned outages for maintenance or construction

Improper design or application, i.e. overloads

Misapplication, i.e. incorrect relay or breaker settings

Human error Failure of utility has supply

F. Analysis and Observations: The results of the calculations provide insightful

information, some intuitive and some not, that can be used as a basis for

recommendations for system improvements. Observations relevant to

improving system reliability at NMSU are discussed below:




Page 4-7

1. Of all components in the system, the Utility source is the least reliable

part of the system. Most effort should therefore be made in developing

configurations that eliminate reliance on a single utility. In the case of NMSU,

this means acquiring another redundant utility supply, and/or relying on

cogeneration for more critical buildings (as long as cogeneration is not the only

source for those buildings). Currently, NMSU relies solely on one source of utility

power (with the exception of Circuit #7 from Geothermal, which has limited

capacity).

2. Configurations that involve cogeneration as a source are more reliable, as

long as the cogeneration is not the sole source of power, and it is setup to be

independent and separate (physically and electrically) from the utility. In other

words, a failure on one will not affect the operation of the other. This is how the

NMSU cogeneration is configured. Systems that rely on cogeneration as the only

source of power, are not sufficiently reliable for more critical buildings. One area

of concern is the large percentage of power that EPE generates using natural gas.

Where both the campus turbine and EPE depend on natural gas, a region-wide

failure in natural gas will result in total power outage to buildings that do not

have a local, standby diesel generator.

3. Buildings with local emergency/standby diesel generators, regardless of

the type of normal power electrical supply serving the building, provide the

highest degree of reliability. For this reason, local generators should always be

considered for buildings that require very reliable electrical system power, such

as data centers or research labs, where the loss of power could result in

significant financial loss or disruption in operations. This would apply only to

loads served by the generator, so a reliable normal supply is still important for

buildings that do not have 100% generator back up.

4. Single points of failure should be eliminated, and the closer the single

points of failure are to the actual load, the more reliable a system is. In other

words, dual paths of power need to be carried as far into the system as practical

for a particular buildings reliability needs. In most cases, this will be on the

primary side of a buildings transformer, and the switch between sources of

power should in proximity to the transformer. While the circuits on the campus

system are generally looped, they all originate from the same switchgear bus at

Tortugus, which is a single-point of failure which could cause substantial outage

time should it fail, and of major concern.




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5. Radial feeds should be avoided. System downtime can be minimized by

switching to another circuit. For the most part, all NMSU circuits are looped.

6. Looping back to same source or bus is only marginally better than a radial

system. The calculations show that there is only a 2% - 3% increase in reliability

over a radial system when the loop is returned to the same utility source and

switchgear bus. The reason for this follows the fact that the utility is the least

reliable component of the system. However, the reliability calculations do not

take into account the convenience of sectionalizing a system for maintenance,

relocation or construction activities that looping provides, even if back to the

same source. Nevertheless, this is still one more reason to develop a

configuration on campus that involves separate lineups of switchgear for the

circuits. Looping back to separate utility supply and switchgear bus has a 35%

increase in reliability over a radial system.

7. Recovery time after failure has a direct impact on system reliability. As

long as there is a redundant supply, the recovery time is limited to the amount of

time it takes to assess and isolate the failure, then switch to the alternate supply.

The actual time it takes to repair a component is taken out of the equation since

the load is being supplied during the repair. In the case of manual switching, the

more simple and accessible a system is to switching operations, the sooner a

system will recover. For the calculations in this report, a 1-hour switchover time

was used from the time of failure to the time when the system is switched to the

alternate supply. This time is lengthened with more complex systems. Larger

distribution systems sometimes incorporate SCADA (supervisory control and

data acquisition) systems in order to quickly locate and isolate failures and

reduce downtime. NMSU has a well-documented switching map, is relatively

straight forward and not too large and therefore the campus would not see

much benefit with a SCADA system.

8. Automatic-switches increase reliability significantly. This essentially takes

the recovery time out of the equation since the alternate supply is immediately

available. However, auto-switch schemes are expensive and complex in that it

could create unpredictable circuit loads and fault conditions if too many

automatic operations are introduced in the system. They can be judiciously

considered for the most critical buildings, such as the campus data center, with

outcomes that are predictable.




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9. Spare components are absolutely essential to system reliability,

especially for larger, long-lead items such as medium-voltage transformers and

switches. The reliability calculations assume that spare components are

available, as typical lead times on transformers and switches encountered on

campus could be as much as 8 12 weeks. Having no spares would result in

unacceptable downtime for a campus environment. It should be systematically

verified that there is at least one spare of every unique component of a system.

10. Older equipment should be considered for replacement first. The longer

a piece of equipment remains in service without failure, the higher the chance is

of pending failure. System reliability considers that its not if, but when a

component will fail. The equipment inventory that was made for the campus

includes age of equipment, and it can easily be prioritized as to which

components should be replaced first.

11. Reducing components in a system increases reliability. The more

switches, transformer cables , terminations etc. that exist in a system, the lower

the reliability of that system. For the most part, the NMSU system does not have

extraneous components. The one exception is the 5 kV 25 kV transformers

that are necessary to maintain the dual distribution voltages on campus. The

long term goal should be to convert everything to the 25 kV system and

eliminate these transformers.

12. Physical separation: while not directly taken into account in the IEEE 497

calculations, physical separation is implied in that if redundant components are

located in the same space, room or trench, the failure of one could cause failure

of the other. Therefore, physical separation is always best practice in electrical

distribution and will be one of the considerations for the recommendations

developed in the next chapter.

G. Building Priority List: Buildings with more critical reliability needs, such as

research buildings, data centers, central plants, etc. should receive the most

attention in terms of cost and effort to increase reliability in the system

delivering power to those buildings, while less critical buildings will be lower

priority for projects affecting reliability. For this reason, main buildings on the

NMSU campus were prioritized based on need for reliable power. The summary

list is included below, and the data is used in making recommendations in the

next Chapter of this study. Input for prioritizing the buildings came from NMSU




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staff during the various charrettes that were held. A priority level 1 is lowest

priority with 3 being highest priority. These numbers are also included in the

Master Building Spreadsheet data in Appendix C. The table below is a summary

of just the prioritization for reliability.

NMSU BUILDING PRIORITY LIST Critical Category Definitions:

1 - Standard campus building with no critical power needs. Outages may average 2 per year and last 1 -2 hours each.

Buildings in this category may include classroom buildings and housing units.

2- Important campus building where outages would cause noticeable disruption and inconvenience. Outages should

not last longer than 30 minutes. Buildings in this category may include: student centers, registrar's office, main dining

halls, athletic venues.

3- Critical campus buildings where outages would cause serious disruption of services, loss of revenue, loss of data or

research. Backup power should be "immediately" available. Buildings in this category may include data centers,

research buildings, central plants, central security/fire monitoring station.

Building Types: Research, Classroom, Housing, Arts/Entertainment, Student Center, Admin, Data Center, Emergency,

Athletic Venue, etc.

Building

Number Building Name Abbreviation Building Type

Critical

Power

Category

(1, 2, 3)

Additional comments

(i.e. reason for

categorization)

264 12" Observatory "A" OBS Teach 1

283 24" Observatory "A" M OBN " 1

602 A Mountain Transmitte AMT Safety/KRWG 1 Whole BLDG Backup

Genset for power

Academic Research Building FSA/CP/EHS 3 Add Backup Genset?

DATA/IT - Followup

Activity Center, James B.

Delamater Student Gym 1

316 Ag Service Storage AGSS Storage 1

343 Air Test Facility ATF Research 1 Low

Alumni & Visitors Cent Public Museum 1

347 Animal Care Facility ACF Research 3 Need Backup Generator

(Desired)

225 Astronomy Building AY Research/Teach/Office 2 On Turbine due to

Convenience of feeder

632 Barnes & Noble NMSU Retail 1

552 Baseball buildings and fields BBO Athletics 1

329 Biological Control Inse BCI Research 1 Low




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NMSU BUILDING PRIORITY LIST Critical Category Definitions:

1 - Standard campus building with no critical power needs. Outages may average 2 per year and last 1 -2 hours each.

Buildings in this category may include classroom buildings and housing units.

2- Important campus building where outages would cause noticeable disruption and inconvenience. Outages should

not last longer than 30 minutes. Buildings in this category may include: student centers, registrar's office, main dining

halls, athletic venues.

3- Critical campus b

Bohannon Huston Site Electrical Infrastructure Master Plan

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