Commitment and Economic Dispatch

COMMITMENT AND ECONOMIC DISPATCH       

INTRODUCTION

Ø   The main economic factor in power system operation is the cost of generating real power.

Ø   Therefore, it is important to focus attention on allocation of real power at generator buses.

Ø   This problem can be partitioned into two sub-problems, i.e.,optimum allocation of generator station at various station load levels and optimum allocation of generation to each station load level and optimum allocation of generation to each station for various system load levels.

IMPORTANT TERMS

Incremental cost

Ø   The rate of change of fuel cost with active power generation is called incremental cost.

Ø   The load balance equation ,  Pg-pd-pl=0.

Participation factor

Ø   The change in generation required to meet power demand is called as participation factor.

Hydrothermal scheduling

Ø   The objective is to minimize the thermal generation cost with the constraints of water availability.

Scheduled reserve

Ø   These include quick start diesel turbine units as well as most hydro units and pumped storage hydro units that can be brought online, synchronized and brought up to full capacity quickly.

Thermal unit constraint

Ø   Minimum up time, minimum down time crew constraints.

Minimum up time

Ø   Once the unit is running, it should not be turned off immediately.

Minimum down time

Ø   Once the unit is decommited, there is a minimum time before it can be recommended.

Crew constraints

Ø   If a plant consist of two (or) more units, all the units cannot be turned on at the same time since there are not enough crew members to attend both units while starting up.