1 Computer Control of Power Systems and Energy Management Systems
2 Outline Introduction Conceptual Model of the EMS
EMS Functions and SCADA Applications. Time decomposition of the power system operation. Open Distributed system in EMS OOPS
3 EMS Enhance the scope of SCADA by providing the power application software to assist the operator in monitoring and control of the electrical network. It consists of three important phases: Gathering Information: Acquisition of real-time data and man machine information. Decision Making. Action by Transmitting Control Orders either - Directly [Centralized Remote Control] - Indirectly [Decentralized remote control or load control].
4 Conceptual Model of EMS
Fig 1. Typical EMS Architecture
5 Real Time Modeling of the system
Network Configuration Analysis Observability Analysis State Estimation and Data processing Network Application Functions
6 EMS Application and SCADA Functions
1. Real-Time Functions · Topological Analysis · State Estimation · Network Equivalent Calculation · Security Analysis · Generation Dispatch · Voltage and Reactive Optimization 2. Extended Real-Time Functions · Short term Load Forecast · Operator Load Flow · Short Circuit Calculation
7 Online and Off line Tasks in an EMS
8 The Functions in the EMS can be classified as
1. Primary Analysis (Perform decision making tasks) Programs for Message Switching. Control of Information Display Systems. Recording of Status and events. Information Processing for telecommand and control 2. Secondary Analysis(Operational planning tasks) State Estimation Optimal Power flow Network Security Analysis Load Prediction
9 Time Decomposition Of Power System Operation
10 Application Functions in Pre-Dispatch, Dispatch and
Post-Dispatch modes of an EMS.
11 Hierarchical Control in EMS
Load frequency Control. Economic Dispatch. Power Exchange with Interconnected utilities. Unit commitment. Maintenance Scheduling
12 On line and Off line Functions
13 Application Programs in an Energy Control Centre
14 Operating States of Power system
15 Description of the Operating states
E: Equality Constraint I: Inequality Constraint 1 Normal 2 Alert 3 Emergency 4 In-Extremis 5 Restorative
16 Different Types of Control Action
No Operating State From To 1 Preventive Alert Normal 2 Emergency Through 3 Corrective Emergency
17 Framework for computer aids for decision making in control centers.
18 Applications for Energy Management Systems and Energy trading Systems
19 Block Diagram of an Integrated EMS
20 Closed System vs. Open System
Open Distributed Systems Closed System vs. Open System Closed system software Restricted to run on a proprietary platform. Data sharing with other computers extremely difficult. Open System software No longer relied on the single vendor to supply all the hardware and software for the EMS Select the each individual subsystem within the EMS from different vendors
21 Impact of Open Systems in EMS
Purchase the hardware and software requirements for the sufficient capacity only - Incrementally upgrade the system as and when required. - This helps in reducing the financial burden on the utilities to change from the closed system to the open system.
22 Object Oriented Programming
Advantages: 1. Reusability 2. Expandability 3. Portability Encapsulation (Data Hiding) 2. Polymorphism (Over Loading) 3. Inheritance (Specialization) Features of OOPS:
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