The Study Of A Comprehensive Power Quality Evaluation Model Based On Cloud Matter Element Theory And Its Application

Reasonable and scientific power quality assessment is the basis for measuring power quality and electricity pricing and it is also a prerequisite for the establishment of a fair electric power market. Firstly, this paper described and analyzed the power quality indicators and accordingly established a comprehensive evaluation index system of power quality, made a scientific division on each indicator according to the latest issued Power quality national standards. And seeing the requirements for users’ involvement in the electric power market improved multi-level interactive decision-making method is used to determine the weight of each power quality indicator which links the superior side (supply side) and the subordinate side (demand side). Interactive and multi-level decision-making methods also get improved. The superior supply side with the coefficient of variation method to determine the initial weights, lower electricity users according to their own the situation with expert scoring method to decide the reported weights, upper and lower levels constantly feedback and synthesize to form the final weight.On this basis, In view of the Power Quality Comprehensive Evaluation own complexity and incompatibility between the classifications, the cloud matter element theory is introduced to carry out a comprehensive assessment of power quality. The application of the normal cloud model to power quality assessment in each level of the junction, based on the normality of the fuzziness of the boundary of the cloud itself, can solve the question of attribution of the boundary values in the vicinity. This method firstly formed the normal standard cloud, calculated the membership of the power quality indicators to each grade of each index, and then combined with the weight of each index to determine the correlation degree of evaluated sites’power quality to the six quality grade. In the last, it introduced the concept of grade strength to judge and analyze the statistical results. Also, this paper increased a calculation formula of the entropy En which provides a new standard for differentiating power quality indicators beyond qualified rating. Power quality assessment procedures based on the cloud matter element theory is written in MATLAB7.0. Examples and analysis show that the method used in this comprehensive assessment of power quality can better reflect the fact, and has its own advantages.Finally, on the basis of a comprehensive assessment of power quality, this paper investigates the application of power quality assessment in the electric power market environment. In the demand side, power quality assessment can be used to power supermarket buyers’and sellers’trading process and the operational process of the regulators. In the supply side, power quality assessment can be potentially applied to the unit economic load dispatch problem in consideration of the impact of power quality.