Kathy Smith FUN-01 ELECTRICITY METERING 101 June 11, 2019...•Used by some utilities to help detect...

Americas HUG

FUN-01 ELECTRICITY METERING 101Kathy Smith

June 11, 2019

© 2019 by Honeywell International Inc. All rights reserved. Confidential and Proprietary.

1

Goals

•Understand electric utility metering quantities and terms

– kWh, kVARh, and kVAh

– Energy and demand

– Power factor and load factor

–Rolling vs. block demand

–Cumulative and continuous cumulative demand

– Transformer rated metering

– Time-of-Use (TOU) metering

– Interval Data

– Power Quality

– Kyz relays


2

Billing Cycles and Read Routes

•Traditionally

–Meters read manually

– “Route” – Meters one meter reader would read in a day

– “Book” – The routes a meter reader would read over a month

– “Cycle” – All the meters read and billed together, includes multiple routes


3

Electric Meters

•Standards

– ANSI – North America, some of rest of world

– IEC – Europe, most of rest of world

•ANSI

– Form – socket wiring

▪ S – socket base

▪ A – A base

–Class – maximum current (amps)

▪ 20,100, 200, 320

–Meet ANSI standards for “revenue” meter

▪ Accuracy

– ANSI C12.20 0.5 % (REX2, REXUniversal)

– ANSI C12.20 0.2 % (A3 ALPHA)

▪ Temperature: -40 °C to +85 °C inside meter cover

▪ Humidity: 0 % to 100 % noncondensing

FORM CLASS TEST AMPS

Form 1S Class 100 15 test amp





Form 3S Class 20 2.5 test amp

Form 4S Class 20 2.5 test amp




Form and Class – Residential


4

Transformer Rated Metering

• Meter “Class” = maximum current allowed

– Class 20

– Class 100

– Class 200 (typical residential)

– Class 320

• Nameplate Voltage range 120 V to 480

• Customer requires > class amps or > 480 volts – how to meter? Install an instrument transformer! Meter will see a fraction of the actual voltage/current.

– Current Transformer (CT) and/or Voltage/Potential Transformer (VT or PT)

– Must meet accuracy standards if used for revenue metering

– Requires multiplier be applied to meter read for billing

– Example – Current Transformer (CT) with 4000:5 rating requires meter readings be multiplied by 4000/5 or 800. Every 800 kwh coming into transformer causes 1 kWh registered on meter.

• Self-contained meter – no transformer

• Transformer rated meter – requires instrument transformer

– Class 20


5

Power Triangle – kWh, kVAh, and kVARh

Pythagorean theorem

kWh2 + kVARh2 = kVAh2


6

Metered quantities “direction”

•ANSI world is from utility perspective

–Delivered = power utility generates and delivers to customer

–Received = power customer generates and utility receives from customer

– Sum = delivered + received

–Net = delivered – received

–Quadrant combinations for kVARh and kVAh

▪ Examples: Q1 + Q4, Q2 + Q3


7

Energy (kWh) and Billing Demand (kW)

•Compare to driving

– Energy = Distance

– Demand = Speed

• Billing demand is highest “peak” demand during billing period

•Demand calculated as average kW over time, typically 15 or 30 minutes

•Example – 15 minute demand

– Travel 10 miles in 15 minutes

– Average speed over 15 minute interval (billing demand) is 40 mph

– May have gone much faster or slower at any point in time

•Both energy and demand affect infrastructure costs

•Convert kWh to kW : kW = kWh * intervals per hour

•Example – 15 minute interval or 4 intervals per hour

– 10 kWh in 15 minutes

– kW for that interval = 10 * 4 = 40 kW


8

Billing Demand Calculations

•Demand = average value of power over a specified time interval.

•Demand interval

– Evenly divisible into an hour

–Common values – 15 or 30 minutes

•Maximum (or peak) demand

–Highest demand value during billing period

– Sometimes called indicating demand

•Demand forgiveness

– Time during which demand is not calculated or stored after a power restoration

–Used by some utilities

Example – 20 kWh in 15 minutes

kW = 20/(1/4) = 80 kW


9

Block Demand vs. Rolling Demand

•Rolling demand

–Defined by two parameters: demand interval and subinterval length

–Demand calculated at the end of each subinterval, resulting in overlapping demand intervals (or a “rolling” demand)

– Used to keep consumers from “splitting the peak” to reduce bill

•Block Demand

– Special case of rolling demand where the subinterval is the same size as the interval


10

Block Demand vs. Rolling Demand

11:05 11:10 11:15 11:20 11:25 11:30 11:35 11:40 11:45 11:50 11:55 12:00

5 min kW 50 55 53 56 104 108 103 98 53 51 55 54

15 min Block kW 52.67 89.33 84.67 53.33

15 min Rolling kW 52.66666754.666667 71 89.333333 105 103 84.66666767.333333 53 53.333333

0

20

40

60

80

100

120

kW

Max rolling demand

billed = 105 kW

Max block

demand billed

= 89.33 kW


11

Power Factor (PF) and Load Factor (LF)

•Power Factor

–Calculated from kWh and either kVAh or kVArh

– Average PF = kWh / kVAh or kWh/√ (kWh2 + kVArh2)

– The higher the PF, the more efficient

•Load Factor

–Calculated from demand

– LF = average kW / peak kW over a period of time or

–Monthly LF = Month's kWh Usage / (Peak kW x 730 hours)

– The higher the LF, the more constant the load is, and more desirable to utility


12

Cumulative Demand

•Used by some utilities to help detect unauthorized demand resets and possible tampers

•Cumulative maximum demand

– Demand reset …

▪ adds the current maximum demand value to the cumulative maximum demand

▪ does not reset cumulative demand to zero

–Unauthorized demand resets do not cause loss of maximum demand data

– Billing demand = this month’s cumulative demand – last month’s cumulative demand

•Continuous cumulative maximum demand

–Updated every time new maximum demand value is determined, not at demand reset

– Equal to the sum of the previous billing period continuous cumulative demand and the current maximum demand


13

Demand and Demand Reset Example

DEMAND RESET


14

Coincident Demand

•A demand value that occurs at the same time as another demand reaches its peak value

•EXAMPLE: record the kVAR demand at the time of a maximum kW demand

•Can be used to calculate power factor at time of peak demand

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9

kW

kVAR

Peak kW in interval 6 = 14 kW

Coincident kVAR demand in

interval 6 = 6 kVAR

Power Factor at time of kW

peak = 0.91914503

Assume 60 minute interval


15

Time-of-Use Billing (TOU)

• Charge customer based on time of day when power is used so price reflects cost

• Typical – up to 4 seasons, up to 4 different rates (tiers)

• Summer

• May through September

• Off-peak 5.327¢ per kWh

• On-peak 17.245 ¢ per kWh

• Weekends and holidays off-peak (Tier C)

• Weekdays on-peak (Tier A) 10 am to 9 pm

• Weekdays off-peak (Tier C) midnight to 10 am, 9 pm

to midnight

• Winter

• October through April

• Off-peak 5.327¢ per kWh

• On-peak 16.341 ¢ per kWh

• Weekends and holidays off-peak (Tier C)

• Weekdays on-peak (Tier A) 6 am to 11 am, 4 pm to 9 pm

• Weekdays off-peak (Tier C) midnight to 6 am, 11 am to

4 pm, 9 pm to midnight

Summer Off-Peak

5.327¢ per kWh

Summer On-Peak

17.245¢ per kWh

Summer

Off-

Peak

5.327¢

per kWh

00:00 9:00pm10:00am 24:00

Winter Off-Peak

5.327¢ per kWh

Winter On-

Peak

16.341¢ per

kWh

Winter Off-

Peak

5.327¢ per

kWh

Winter On-

Peak

16.341¢ per

kWh

Winter

Off-

Peak

5.327¢

per kWh

00:00 9:00pm 24:004:00pm11:00am6:00am


16

Self Read

•Snapshot of all current register values

– All tiers (A, B, C, D, Total)

– All energy quantities

– All demand quantities (Maximum, Cumulative)

–May or may not have demand reset

–Done at midnight

•A3 ALPHA & REXUniversal – program when you want self read

– Every day

– 1st of month

– etc.

•REX2 – daily at midnight

•Why?

–Historically – monthly billing snapshot on 1st, meter manually read any day

– Today – daily billing snapshot at midnight for pre-pay, MDM


17

Interval Data

•Capture data on a regular interval – e.g., 5, 15, 30, 60 minutes

• Interval time stamp – at end of interval

– 60 minute interval with time stamp 2:00 contains data from 1:00 to 2:00

•Historically

– Small subset of customers of all classes – rate research

– Largest customers – billing

– Initially – magnetic tape recorders

•Today may be desired/required for all customers

–Government requirement (Ontario)

–Calculate bills (straight kWh, TOU, demand, other)

–Customer portal

–Customer service

– Theft detection

–Other calculations – coincident peak of entire feeder, transformer, etc.

010203040

1:0

04:0

07:0

010:0

013:0

016:0

019:0

022:0

0


18

Interval Data

•Can be energy (“load”) values (kWh, kVARh, etc.) or instrumentation values (voltage, current, etc.)

– Each different value recorded is a “channel”

▪ Remember it started with magnetic tape!

–Meter can record multiple channels

▪ Example – kWh delivered and kWh received for net metering applications


19

Interval Data

•Pulse divisor for energy quantities – scale values to fit in meter

•A3 ALPHA and REXUniversal

– Programmed with Metercat

– Each A3 interval can store 32,767 pulses before overflowing

– Each REXUniversal interval can store 4,095 pulses before overflowing

– The range for the value of the load profiling pulse divisor is 1 (default) to 255.

•REX2

– Set in factory, based on Programming Form

– Each interval can store a maximum of 4,095 pulses before overflowing

– The range for the value of the load profiling pulse divisor is 1 (default) to 255


20

VEE and EOI and midnight reads

•VEE - Validation, Editing, and Estimation of interval and register data

•Standard interval data validation test – sum check

–Requires two meter readings, one at each end of interval data

–Difference between meter readings should equal sum of intervals

– AMI world expects meter readings exactly at end of interval (EOI) or midnight –some MDMs can only work with midnight reads

– Example

▪ 1:00 start meter reading =10

▪ 7:00 end meter reading = 40

▪ Difference = 30

▪ Sum of intervals = 5+6+4+6+5+4 = 30

0

2

4

6

8

1:00 2:00 3:00 4:00 5:00 6:00 7:00

Interval Data

kWh


21

What is kyz?

•Relay in meter (A3 ALPHA)

•For each Ke (pulse) transition of the selected quantity, the relay will either:

– toggle

– pulse for a specified pulse width

•Programmable with meter software (Metercat)

•Used to provide customer with real time billing quality demand information for Energy Management System

– Verify utility bill

–Control demand

–Compare different sites

– Etc.

•Typically for large customers

•May feed a “recorder” that collects interval data


22

Industry Acronyms and Terms

Term Definition

AMI Advanced Metering Infrastructure

AMR Automatic Meter Reading

C&I Commercial and Industrial customers

CIS Customer Information System (Billing System)

DMS Distribution Management System

DR Demand Response

DSM Demand Side Management

EMS Energy Management System

GIS Geographic Information System

MDM Meter Data Management

OMS Outage Management System

SCADA Supervisory Control and Data Acquisition

WMS, WOMS Workorder Management System


THANK YOU !

Kathy Smith

Sr. Software Services Architect

Raleigh, NC

[email protected]

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Kathy Smith FUN-01 ELECTRICITY METERING 101 June 11, 2019...•Used by some utilities to help detect...

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