Transmission Line Fault Location Using Unsynchronized Measurements

Abstract

Designing reliable and accurate fault locating algorithms is still considered a challenge despite the intense research and development efforts transcribed in literature. Modern power system networks have grown in complexity and the increased deregulation of utility markets have helped dedicated fault locator systems garner much attention. Traditional electro-mechanical distance relays can be considered the first in a series of attempts to realize the aim of fault distance location. However, these were designed to provide rapid and reliable indication of the general faulted area rather than furnish fault distance estimates with pin-point accuracy. On the other hand, fault locator systems are expressly designed to provide accurate, reliable and reproducible fault distance solutions that might work with single-ended or two-ended data measurements. The two-ended data measurement provides far more accurate results. However data synchronization between protective relays at both ends is another issue that demands careful consideration. More often than not, modern fault locating algorithms incorporate integrated communication capabilities with sophisticated computational routines to furnish fault location estimates within an acceptable range of accuracy. In this thesis, the solution to transmission line protection problem is modeled as a fault locating algorithm that utilizes unsynchronized measurements. Two new fault locating algorithms are designed for two fundamental power system topologies: multi-terminal or multi-tap transmission line systems and compensated power transmission lines. Compensated transmission lines might incorporate fixed series compensation (FSC) or shunt reactor compensation. Evaluations of the algorithms substantiate enhanced fault location accuracy and robustness against power system transients. Moreover, the accuracy of fault location solution and synchronization procedure is not dependent on the mode of operation of non-linear FSC devices and copes well with temporary turbulences caused by power system transients.