A voltage sag source location method based on optimal matching of positive sequence voltage at multiple measuring points

Abstract

The invention relates to a voltage sag source locating method based on multi-measuring-point positive sequence voltage optimal matching. First, the positive sequence voltage variations of multiple measuring points before and after a fault constitute a failure mode as characteristic values, and mode similarity is defined. Then, a fault is preset at the midpoint of each branch to form a typical mode group, the similarity between a to-be-identified mode composed of positive sequence voltage measurement values of the measuring points and the typical mode group is obtained through matching, the typical mode group is clustered into multiple sub groups according to the similarity, and lines corresponding to the sub groups with maximum similarity constitute a primary fault line set, and thus, the locating search space is narrowed. Finally, an optimal estimation model is built by taking the maximum of similarity as an objective function and the fault line number and fault distance in the primary fault line set as optimization variables to find an optimal matching fault mode, and the model is solved using an adaptive particle swarm optimization algorithm to determine the fault line and fault location. The method can effectively overcome the influence of fault type and transition resistance on voltage sag source locating, and is of high locating precision.

Description

technical field [0001] The invention relates to a method for locating voltage sag sources based on optimal matching of positive sequence voltages at multiple measuring points. Background technique [0002] As more and more sensitive loads are connected to the grid, users are increasingly concerned about voltage sags. Short-circuit faults are one of the main causes of voltage sags. Accurately locating the source of voltage sags will help power grid companies eliminate faults as soon as possible and improve power supply reliability. [0003] At present, the location methods of voltage sag sources are mainly divided into two categories: single-point orientation and multi-point location. The methods based on single measuring point orientation mainly include disturbance power and energy method and its improved method, system trajectory slope method, real part current method, disturbance active current method, equivalent impedance real part method, distance relay positioning meth...

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Problems solved by technology

However, most of these methods fail to overcome the influence of fault types and transition resistance on the location of voltage sag sources, and are difficult to apply in engineering and large-scale power grids.

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