Study Of Evaluation Method On Steady Power Quality

Evaluation of power quality is the premise of "pricing according to the quality" in the electricity market.Based on the method of probability and statistics; it proposes a new single index method of power quality evaluation. The expectations and variance of the power quality indices'probability distribution are been for grading at the same time. Then it obtains the expectations level and variance level to be evaluated index .finally it gets the level of the indicator. The method avoids relying solely on expectations of a hierarchy, and giving a large degree of deviation of dispersion. In the comprehensive evaluation of power quality, the paper combines the entropy weight with the specialist subjective weight to decide the synthetic weight, and sufficiency considers objective factor and subjective factor. The positive and negative TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) matrixes are composed of every space's corresponding frontpoint and endpoint of order of evaluation. It seeks the relational degree between evaluation point and them to establish the quality synthetic evaluation model by gray relative analysis method. This approach achieves a more satisfactory assessment of power quality.