UNIT COMMITMENT IN HYDRO-THERMAL SYSTEM

Abstract

In a complex system with many generating units of various types, the proper selection of start up or shut down of units helps in system economy. The study of 'Unit Commitment?, presumes that generation is higher than the system load, otherwise all the units must be run with-out thinking for any saving. Till last decade, only generation scheduling was popular. Later, many studies were done, created large scope of savings in system overall generation, through proper Unit Commitment. Here, the optimisation of system co st have been discussed in case of thermal Units. In case of thermal Unit Commitment, a new idea about the procurement of fuel have been detailed out. In fact, the procurement policy for fuel must be such that it is neither in excess nor in shortage. Otherwise, a penalty cost involves in system generation. Direct iterative, combination trial and Dynamic Programming methods, have been adopted to solve the 'Unit Commitment' problems for different sample systems. Hydro Unit Commitment depends on many factors such as head, discharge, storage, efficiency etc. But, in a plant, the acting head on all the units is same, so the main basis for Unit Commitment becomes only the discharge and efficiency of, each unit. To have the minimum discharge for a given load, the units selection have been done, using Dynamic Programming Approach. Security in supply is a very important aspect for any reliable system. A system Unit Commitment may be economically optimal, but before going to a final stage, the reliability index must be checked. Generally, the basic unit commitment.- requires some modification to satisfy the security of supply. On Line Computer application may help the system operator to decide quickly the generation and thereby helping in the economy. In fact, the time has come to see for any possible savings in planning, operation and maintenance, which leads to the minute studies of 'Unit Commitment'.