Improving the Efficiency of Earth Fault Detection by Fault Current Passage Indicators in Medium-Voltage Compensated Overhead Networks

Abstract

The article presents a method for detecting earth faults in a compensated medium-voltage network, which can be used especially in fault current passage indicators, but also in standard protection devices. The method is based on the adaptation process of the zero-sequence current protection setting, with the adaptation factor depending on the current value of the zero-sequence voltage. In this article, a comparative analysis of the classical and adaptive zero-sequence current criterion is conducted, taking into account the errors of the measuring system. The results of simulations performed in the PSCad environment are also presented. For a representative set of example short circuits, it was shown that the effectiveness of the presented criterion can be more than 50% higher than that of the standard criteria, taking into account the range of detected transition resistances. A comparison of the proposed method with admittance criteria was also drawn, and it was shown that it is suitable for the detection of high-resistance earth faults.

Application of Under-Impedance Criterion to Protect against Effects of Phase-to-Phase Short Circuits in Medium-Voltage Networks

“…The need is indicated both by the opinions of practitioners dealing with energy distribution [15] and by numerous scientific publications on this subject [16,17]. They include proposals for alternative solutions for commonly used protection in MV lines [18][19][20][21], including overcurrent protection [22][23][24][25]. The article will present arguments for the introduction of protection using the principle of impedance measurement in MV lines, which seem so convincing that it is even advisable to introduce them as a standard in energy companies.…”