The Rules for Using Modal Transformation in Traveling Wave Fault Locator

Abstract

The accuracy and stability of a single-end traveling wave fault locator directly depend on the correct construction of electrical network model in fault regime. In the regime of ground short circuits this task becomes more difficult due to the need to take into account the components of aerial and ground (zero) modes of power line in the electrical network of fault regime model. Its incorrect solution leads to a decrease in the accuracy of determining the arrival time of the used traveling wave, which, in turn, decreases the accuracy in calculating the distance to the fault. In order to correctly construction of electrical network of fault regime model and accurate estimation the used traveling wave arrival times in locators phase-modal transformation is performed. Such a transformation for single-circuit power line can be one of the invariant Clarke, Karrenbauer or Wedepohl transformations. The classical representation of these transformations cannot be directly applied to the electrical values of a double-circuit power line, consisting of six wires and, accordingly, having six independent modes. The purpose of this article is to illustrate the application of the modal transformation matrix for divide the electrical values of a double-circuit power line into independent components.