Research And Application On Steady-state Power Quality Synthetic Evaluation Method

With the rapid development of our economy,the demand for electricity power is increasing at an incredible rate.The application of lots of non-linear loads and power electronic component is attracting more and more attention of researchers.Therefore,how to evaluate power quality rationally and scientifically is becoming an important step to improve power quality.At the same time,it can provide a reference to decide to the power price according to power quality in the environment of power market.In terms of steady state power quality evaluation,it refers to many indexes and belongs to synthetic evaluation problem.At present,Chinese National Standard have made some limits about individual power quality index.It is crucial to evaluate power quality considering multi-indexes.According to the requirement about different indexes,a power quality synthetic evaluation model is built including frequency deviation,voltage deviation,voltage harmonic,voltage fluctuation,flicker and three phase voltage unbalance.On the basis of related literature,an improved radar chart model is built considering weight of different indexes.After getting the radar chart,an evaluation function is used to reflect the degree of power quality and radar chart is a good tool to reflect power quality intuitively.In order to get an objective evaluation results,some training data is formed to build the Fisher discriminant analysis model based on interpolation method.Then these training data is used to test the accuracy of the proposed model.Finally the Fisher discriminant analysis model is used to evaluate the power quality in this paper.