27

Substation

Remote terminal unit

SCADA Master Station

Com

mun

icat

ion

link

Energy control center with EMS

EMS alarm displayEMS 1-line diagram

Simple basics• What is SCADA?

– Supervisory Control– Data Acquisition

• Purpose of SCADA?• What else now needed

– Controls – Look into future & able to control future events

• What is EMS?• Need for EMS?

Simple basics

• How to look into the future?• How to know present problems/state?• How & what actions to take?• Which are best actions?• Optimisation?• How can we control the events?

Simple basics

• What is State Estimation (SE)?• Why is it required?• How is it achieved?

– Techniques?– Process?

Need of the Modern Load Dispatch Center

• A robust Energy Management System capable of meeting the requirements of changed scenarios of deregulated market mechanisms.

• The EMS system shall be capable of being easily integrated with Market Management System.

7

Requirement of EMS Functions.

• Why do we need EMS functions?• Help grid operators in decision making .• Gives scientific logic for any actions.• Gives warning for any emergency situation.• Power system can be analysed for different

operating conditions.• To get a base case for further Analysis• ….

EMS functions objective

• Power system monitoring

• Power system control

• Power system economics

• Security assessment

EMS Functions : Classification Based on Function

1. State Estimation

2. Power Flow Analysis

3. Contingency Analysis

4. Security enhancement

EMS Functions : Classification Based on Time Domain

• Pre Dispatch Functions• Load Forecasting/Inflow

forecasting• Resource Scheduling And

Commitment• Network Outage Planning

• Real Time Operation• State Estimator (RTNET)• Real Time contingency analysis

(RTCA)• Real Time Security Enhancement

(RTSENH)• Real Time Generation Control

(RTGEN)• Voltage Var Dispatch

• Post Dispatch / off line activities

• Dispatcher training Simulator

• Other features like– Historicar Data Recording,– Historical Information

Management,– Sequence Of Events,– Load Flow Studies ( STNET)– ….

Quantity to be

telemetered

Transducer A/D converter

Telemeter transmitter

Telemeter receiver

Computer

D/A converter

Indicating meter

Recording meter

Signal circuit (wire line, PLC, microwave, etc.)

Figure 5b: Bus-branch representation Figure 5a: Breaker-switch representation

DyLiacco’s operational decision paradigm

Normal (secure)

Emergency

Restorative

Extreme emergency.Separation, cascading

delivery pointinterruption,

load shedding

Alert,Not secure

Transmission loading reliefprocedures

SCADA

Overloads & Voltage Problems

Potential Overloads &

Voltage Problems

Breaker/Switch Status Indications

System Model Description

Telemetry & Communications equipment

State Estimator

Network Topology program

AGC

Economic Dispatch

Calculation

OPF

Contingency Selection

Contingency Analysis Security Constrained OPF

Display Alarms

Updated System Electrical Model

Analog Measurements

Display to Operator

Power flows, Voltages etc.,

Display to Operator

Bad Measurement Alarms

Generator Outputs Generation Raise/Lower Signals

State Estimator Output

Substation RTUs

Mediciones

Filtracion

Estimacion deEstado

Topologia de lared

Pronostico decarga en la barra

Modelamientoexterno de la red

Flujo de carga enlinea

Evaluacion deContingencia

Seleccion deContingencia

verificacion delimites

Procesamiento dedatos erroneos

Analisis deObservabilidad

Estadonormal

Estadoemergencia

Estadorestauracion

SISTEMA DE POTENCIA

OPERADOR DEL SISTEMA

CONFIGURADOR ESTIMADOR PREDICCION DE LA CARGA

AGC

PLANEAMIENTO OPERATIVO

SUPERVISION TIEMPO REAL

EVALUACION DE CONTINGENCIA

ESTRATEGIAS CORRECTIVAS

OPERACIÓN ECONOMICA

EQUIVALENTES EXTERNOS

SELECTOR CONTINGENCIAS

PREDICCION DE CARGA

FLUJO DE CARGA EN LINEA FLUJO DE CARGA

OPTIMO