BEEE06

POWER SYSTEM OPERATION AND CONTROL


OBJECTIVE: To gain the concepts of economic load dispatching and power frequency control and reactive power control of power systems.

1.INTRODUCTION

Approach adopted in utilities for providing reliable, quality and economic electric power supply- necessity for regulation of system frequency and voltage - p-f and Q-V control structure- Recent trends in real time control of power systems- Load dispatching- System load characteristics- load curves- chronological load curves- load duration curves- energy time curves- load factor- utilization factor- diversity factor- coincidence factor- demand factor- reserve requirements- installed reserve - spinning reserve- cold reserve- hot reserve- operational restrictions- load dispatching.

2.PRE-REQUISITIES TO LOAD DISPATCHING

Load forecasting - components of system load- classification of base load- forecasting of the base load by method of least square fit- introduction to unit commitments- constraints on unit commitment- unit commitment using priority ordering.

3.POWER FREQUENCY CONTROL

Local control- Power control mechanism of individual machine- mathematical model of speed governing mechanism - speed load characteristics of governing mechanism- regulation of two generators in parallel- System control- Division of power system into control areas- LFC control of a single area- static and dynamic analysis of uncontrolled system- proportional plus integral control of a single area- LFC control of two area system - uncontrolled case- static and dynamic response- Tie line with frequency bias control of two area.

4.ECONOMIC DISPATCH CONTROL

Incremental cost curve- co-ordination equations with loss neglected - solution by iteration- co-ordination equations with loss included (No derivation of Bmm co-efficients)- solution of co-ordination equations using Bmm co-efficients by iteration method- Base point and participation factors - Economic dispatch controller added to LFC.

REACTIVE POWER VOLTAGE CONTROL

Local control- Fundamental characteristics of excitation system- block diagram model of exciter system- System control- Generation and absorption of reactive power- method of voltage control - Injection of reactive power- static shunt capacitor/Inductor VAR compensator- Tap changing transformer.