TRANSMISSION LOSS EVALUATION BASED ON PROBABILISTIC POWER FLOW

A simulation method of the composite power system is proposed for the purpose of evaluating the probability distribution function of transmission losses. The method accounts for uncertainty of the electric load, availability of generating units, nonlinearities in the power flow equations, and major operating practices. The method is based on the following procedure. First, given the probabilistic electric load model, the probability distribution function of the power injection at generation buses is computed by taking into consideration the availability of generating units and economic dispatch practices. Next, transmission losses are expressed as a piecewise linear function of power injections at generation buses. Subsequently, the probability distribution function of transmission losses is computed. Validation of the method is performed via Monte Carlo simulation. The method has been applied to the 24 bus IEEE reliability test system and the results are validated by comparing it to Monte Carlo simulation results. The method has also been applied to the Georgia Power Company's composite system (1304 buses, 98 units, 1546 lines, 117 transformers) and the results are presented. The efficiency of the method is also documented with timing on the 1304 bus system.