Post on 25-Mar-2018
Online Monitoring of Electrical Energy – A step towards
Modern Energy Management System
in Durgapur Steel Plant
Somak Dasgupta
CET, SAIL, Durgapur Sub Centre, Ispat Bhawan - 7th Floor,
Durgapur Steel Plant, Durgapur-713203
Tel: +91-343-2582687
Email:somak.dasgupta@sailcet.co.in
Electrical Energy Management System (EEMS) refers to a system designed specifically for
automated control and monitoring of electric power and utility system.
As per directive of Bureau of Energy Efficiency, all steel plants of SAIL are required to
fulfil the energy consumption target as per Perform, Achieve and Trade (PAT) scheme. The
present practice of Power Management Department of Durgapur Steel Plant (DSP) is to
note down the energy consumption readings from the conventional electromagnetic type
meters and calculate them manually. Need was felt for an automated system to monitor
and subsequently control the electrical energy consumption of different units of the plant.
The proposed paper describes the scheme of setting up of an online energy monitoring
system (OLEMS) connecting 146 nos. of panels with retrofitted multifunction meters
(MFM) spread over 16 nos. sub-stations throughout the plant. The existing DSP Local
Area Network (LAN) will be utilized as the media for data communication from different
substations to OLEMS server at Main Receiving Station (MRS) control room.
Key Words: EMS, energy, online, monitor
INTRODUCTION
Electrical Energy Management System (EEMS) widely refers to a computer system which
is specifically designed for the automated control and monitoring of electric power and
utility system.
ABSTRACT
Energy Management System (EMS) is a collection of computerized tools used to monitor,
control and optimize the performance of generation and transmission systems. The
intelligent energy management software control system utilizes real time system data and
is designed to reduce energy consumption, improve the utilization of the system, increase
reliability and predict electrical system performance as well as optimize energy usage to
reduce cost.Energy Management System had its origin in the need for electric utility
companies to operate their generators as economically as possible. It involved efficient
on/off scheduling of generating units. Energy Management Systems can also provide
metering, sub metering, and monitoring functions that allow facility and building managers
to gather data and insight that allows them to make more informed decisions about energy
activities across their sites.
EMS IN POWER SYSTEMS
EMS is related to the real time monitoring, operation and control of a power system. The
information from the power system is read through Remote Terminal Units (RTU), an
integral part of SCADA to an EMS system or Energy Control Centre (ECC). EMS consists
of both hardware and software. Hardware part of EMS consists of RTU, Intelligent
Electronic Device (IED), Protection, Computer networking, etc. Software part of EMS
consists of Application programs for network analysis of power systems. In EMS,
application programs are run in a real time as well as extended real time environment to
keep the power system in a secure operating state. Now-a day’s EMS is an integral part of
any power system. It is used as a part of Substation Automation System (SAS), Demand
Side Management (DSM), Protection and Distribution Management Systems (DMS), for
renewable energy and so on.
OBJECTIVES
Primary objectives are maintaining the power system in a secure and stable operating state
by continuously monitoring the power flow and voltage magnitudes, maintaining the
frequency and the tie line power close to the scheduled values.
Secondary objectives are economic operation of power system through real time dispatch
and control and optimal control through preventive and corrective actions.
Tertiary objectives are optimization of the power system for normal and abnormal
operating scenarios and maintenance scheduling.
The three objectives are executed at different levels by the operator in a control centre.
While the first objective is automatic or closed loop control without manual intervention
the other objectives performed with the aid of the operator.
EVOLUTION OF EMS
The evolution of EMS has a long past. It has started with control centres in 1960s to fully
developed energy management systems.
During 60’s, the Control Centres (CC) were introduced to control and the power generation
and load demand so as to match the generation with load demand.
During 70’s, Energy Control Centres (ECC) came into existence to mainly manage the
energy rather than power.
During 90’s EMS were formed to manage the energy through various techniques like Load
Management, Demand Side Management, etc. EMS uses computer based programs that
perform both computational tasks as well as decision making tasks to assist the operator for
real time and control.
The evolution of SCADA started with monitoring and data acquisition systems of plants
followed by control. These have been used prior to EMS. The main tasks of SCADA were
to continuously measure and monitor parameters for checking limit violations and to
ensure reliable and safe operation of the system. It becomes more beneficial when EMS
and SCADA are used together.
OPERATION AND FUNCTIONS OF EMS
EMS consists of several application programs which are used by the operator in a control
centre for effective decision making in the operation and control of a power system. These
application programs are specific programs like load forecasting, security assessment,
contingency analysis, optimal power flow etc. which monitor and calculate the operating
states of the power system.
All of these programs are networked together in such a way the output of one program is
the input to another. This continues till all the programs form a closed loop. The output of
each program provides a result which can be used by the operator for decision makingfor
controlling the power system.
The working of an EMS is divided into two categories, namely “online” or “offline”
corresponding to the problem being addressed and the application it is handling.
The operation has three main classifications namely
i) Online closed loop control like load frequency control, automatic generation
control, reactive power control, voltage control
ii) Online open loop control like active & reactive power dispatch
iii) Offline study or simulation model
The following are the important functions which are carried out by EMS:
Control functions:
1. Real time monitoring and control functions
2. Automatic control and automation of a power system like automated interfaces and
electronic tagging
3. Efficient automatic generation control and load frequency control
4. Optimal automatic generation control across multiple areas
5. Tie line control
Operating functions:
1. Economic and optimal operation of the generating system
2. Efficient operator decision making
Optimization functions:
1. Optimal utilization of transmission network
2. Power scheduling interchange between areas
3. Optimal allocation of resources
4. Immediate overview of power generation, interchanges and reserves
Planning functions:
1. Improved quality of supply and system reliability
2. Forecasting of loads and load patterns
3. Generation scheduling based on load forecast
4. Maintaining reserves and committed transactions
5. Calculation of fuel consumption, production cost and emissions
The functionsof an EMS are illustrated in Figure-1 and 2. Figure-1 shows the measurement
of voltage and current through current transformer (CT) and voltage transformer (PT) or
through remote terminal units (RTU). These are inputs to the EMS of the control centre.
Figure-2 illustrates the various EMS functions in an EMS. State estimation forms the first
and foremost function that is executed based on SCADA measurements. The output is used
by many other programs.
Fig.1.0: Measurement and monitoring
Fig.2.0: EMS functions
ENERGY MANAGEMENT SYSTEM IN DSP
BACKGROUND
DSP receives bulk power from DVC. The balance power is obtained through self-
generation from Old Power Plant (OPP) and NSPCL. The power from DVC is received at
Main Receiving Station at 220 KV and stepped down to 33KV through 80MVA
transformers for onward distribution. Step down substations are situated at various load
centres to feed power to different units of the plant like Coke Oven complex, Sinter plant,
Blast furnace, SMS complex and Rolling Mill complex together with associated auxiliary.
As per directive of Bureau of Energy Efficiency, all steel plants of SAIL are required to
fulfil the energy consumption target as per Perform, Achieve and Trade (PAT) scheme.
The present practice of Power Management Department of Durgapur Steel Plant (DSP) is
to note down the energy consumption readings from the conventional electromagnetic type
meters and calculate them manually. Readings are taken once in a month. Continuous
monitoring is not possible as number of monitoring points is very high and involves
manpower. Need was felt for an automated system to monitor and subsequently control the
electrical energy consumption of different units of the plant.
PROJECT OVERVIEW
The EMS system will collect data from Multifunction meters (MFM), for the 33kV, 11kV,
& 3.3kV power distribution network, over MODBUS RTU protocol via DSP LAN from
sixteen substations of DSP. Multifunction meters will be retrofitted in 146 breaker panels
throughout the plant for which the energy monitoring will be done. The existing DSP
Local Area Network (LAN) will be utilized as the media for data communication from
different substations to OLEMS server at Main Receiving Station (MRS) control room.
A new Local Area Network (LAN) will be set up in Main Receiving Station (MRS)for
communication between Online Energy Monitoring System (OLEMS) server, clients,
printers, existing SCADA (ECIL) and existing network switch of DSP LAN in the control
room.
PROJECT ARCHITECTURE
The existing substations, for which the EMS will be implemented, are distributed
throughout the plant. An existing network switch of DSP LAN may either be located inside
or far from a sub-station.Accordingly, the architecture will be different in both the cases.
The MFMs will be serially connected through RS485 cable and connected to the Ethernet
gateway which in turn will be hooked up to the existing network switch. The connection
arrangement of MFM using the existing CT/PT/Auxiliary is given in Figure-3.
In case the network switch is located outside the sub-station, optical fiber cable will be
used for hooking up. The architecture of sub-station MFMs is shown in Figure-4.
The MFM data will be dumped into the LAN andthe data will be fetched from the network
switch located in the MRS control room. A LAN will be set up in MRS control room to
accommodate the server hardware. The architecture of server hardware is shown in Figure-
5.
PROJECT WARE
Following items will be installed for EMS:
SL
No Item Name
Make/
Model Descriptions Qty
1 MFM 0.5s
CMS RM705
L4
Bi-Directional revenue energy metering. Voltage &
Current, KW, KVA &KVAR, Power Factor,
Frequency Energy: Import & Export KWH,KVARH
Lag, Voltage & Current unbalance %, Display
current Date & Time, Phase Wise KWh 150
2
RS485 to
Ethernet
Converter Netex 103
Interface for Modbus TCP and Modbus RTU
22
3
Media
Converter
D-Link DFE
855S-15i
Media converter converts 10/100BASE-TX Ethernet
twisted –pair signals to 100BASE-FX fast Ethernet
fibre signals. 18
4
UPS
Offline
APC
BR1000 G
1.0kVA, Supply : 210-230VAC, 50Hz, Output:
220VAC, 50Hz, 5
5 FL 9U rack WQ 600mmW x 500mmD and 9U usable Height 15
6
Network
Enclosure
Box WQ
600mmW x 500mmD and 9U usable Height
18
7 LIU Molex 12 Port LIU box fully loaded 18
8
Network
Switch
CISCO
SG300-10P
8 Port, 19” Rack Mountable, 10/100/1000BaseTx
RJ45, RS232 Console port and GBIC/ SFP Slot 5
9
N/W
Firewall
CYBEROA
M Cyber roam DPU CR 25iNG 1
10 Server PC
HP
ML350T09 HP ML350T09 G9 1
11 Client PC
DELL
OptiPlex
3020 Intel I3 Processor of latest architecture 2
12 Laptop
LENOVO
B40 80 Intel I3 500SU 1
13 Printer
CANON
LBP6230DN
LAN interface, Resolution-1200 X 1200 dpi, Paper
Size-A4 2
14 UPS Online
Emerson
Liebert GXT
MT
1.0kVA, Supply : 210-230VAC, 50Hz, Output :
220VAC, 50Hz 3
15
UPS for
Switch APC
Supply : 210-230VAC, 50Hz, Output : 220VAC,
50Hz 2
16
EMS
Server
Software CMS Envisage EMS software 1
17
EMS Client
Software CMS Envisage EMS software 2
18 Furniture Standard Computer Table & Chair 3
19 UTP Cable Molex Cat6 UTP Cable
1500
Mtr
20
RS 485
Cable
KabirInfosol
ution Pvt
Ltd. RS 485 Armoured Cable
2000
Mtr
21 GI Conduit UTKARSH 0.5” GI Conduit
800
Mtr
22
PVC
Conduit UTKARSH 0.5” PVC Conduit
1200
Mtr
23 HDPE Pipe UTKARSH 1.00” HDPE pipe for FO Cable
2000
Mtr
24 FO Cable Molex 6 Core Armoured Single core FO Cable
2000
Mtr
25
Power
Cable Finolex 2.5sq. mm (Red, Yellow, Blue & Black) Power cable
4500
Mtr
CONCLUSION
The introduction of EMS in DSP will result in continuous monitoring and analysis of
electrical energy consumption of selected load points throughout the plant. It is a stepping
stone for introduction of automated electrical energy control which in turn will optimize
the energy utilization in future.
REFERENCES
1. Steve Doty & Wayne C Turner - Energy Management Handbook, Eighth edition, Nov 2012
2. SaniaAman, Yogesg S and Prasanna V.K - Energy Management Systems: State of the art and
Emerging Trends- IEEE Communications Magazine, Vol.50, No. 1, 2013
Somak Dasgupta