Probabilistic Operation of Electric Power Systems Considering Environmental Constraint (Part 9)* -A Fast Scheduling Method-

A scheduling method for electric power systems is reported. The schedule is made to satisfy the limits of both system security and environmental pollution. The limit of system security is considered as the probability of the power supply. And power supply is considered possible only when every power flow satisfies each transmission line’s capacity in this report. Each thermal unit and line are considered to suffer a failure probabilistically. The nitrogen oxide emission from thermal stations is considered as a typical example of environmental pollution. Its limit is considered as a total value for all thermal units. Two methods of approximation are introduced so that the schedule can be estimated rapidly. The first is a method of adjustment of the output power of thermal units to satisfy the line capacities. 0nly two units adjust their power to satisfy them approximately. The second is the control of the emission. It is controlled by only one system state whose elements are all healthy, which may not introduce a strictly economical schedule. The proposed method is applied to a model system. Results of simulations are shown by some kinds of limits. That is, the probability of power supply is improved by about 15 [％] with the proposed method. The emission can be reduced by about 10 [％]