Comparison of the Influence of Different Types of Faults on Four-Circuit Transmission Lines on the Same Tower

The risk of failures on multi-circuit transmission lines on the same tower becomes higher and the fault types are more complex. Sometimes maybe we need to analyze the influence of faults between different lines and the phase-to-phase faults on one line in such a system especially when the voltage grades are high and the transferred power is big. Knowing the severity of the different fault types in advance can help us to better analyze such systems and save simulation time. However, by now the related researches are rare. This paper derived the equations of the transferred power by four-circuit transmission lines on the same tower during different faults in a simple system based on the symmetrical component method, Equal Area Criterion and some assumptions. According to the equations the paper compared the severity of the different types of faults and get some conclusions. A simple test case is used to testify the correctness of the equations and the conclusions.