Application Of PLF In District Power Grid

There are many uncertain factors in power system operation, such as fluctuation of loads, the forced outage of generation and the fault in transformer equipments. The generalized power flow needs much computation and is hard to reflect the all-around conditions. Probabilistic Load Flow (PLF) uses probability statistics to solve the random variations in power system operation, provides the seventh-order cumulant of voltage, and reveals much more of the operation status, problems and weakness in power system, which offers much more intact information for grid planning and operating decision.Firstly, the calculation model of PLF is introduced, such as the probability model of load power and generator, as well as linearizing ac model. The distribution of load power is normal distribution and the output of generator is binomial distribution. Secondly, this paper introduces the semi-invariant of randomly distributing, which can simplify the convolution operation whose calculation volume is very large to plus and minus of several semi-invariant, and this can improve the whole computational efficiency.Thirdly, the calculation procedure of PLF is presented. The programmed algorithm is programmed by VB 6.0 according to this paper. System IEEE14 is used to verificate the feasibility of PLF and the results indicates that the algorithm is effective and feasible.Finally, the calculation of PLF under the maximum operating mode in Liaoyuan of Jilin province is presented. The result is comparated with generalized power flow .In addition, the function of PLF design in Liaoyuan PAS is given as well.