Abstract:

In order to effectively evaluate the power quality of regional power grids,a dynamic evaluation algorithmbased on the vertical and horizontal scatter degree method,which makes full use of the current and historical dataand reflects the overall level of the evaluated objects in a certain period,is proposed.In the investigation,the synthesizedweights of power quality indexes are determined via the vertical and horizontal scatter degree method andthe sequence-relation analysis,in which the objective weights are used to highlight the overall differences of theevaluated objects and the subjective weights are used to reflect the expert experience.Then,by linearly weightingeach index,the evaluation value of power quality in each period is obtained for each evaluated object. Moreover,the least variance method is employed to compute the sum of the evaluated power quality in each period for a regionalnetwork; therein the time degree is adjusted to emphasize the current and the historical data. The performance ofthe proposed algorithm is finally verified by a case study on the power quality of a power supply bureau.

Key words: power quality, dynamic evaluation, vertical and horizontal scatter degree method, least variance method