Earth Fault Location Using Negative Sequence Currents

Abstract

In this paper, a new method for locating single-phase earth faults on non-effectively earthed medium voltage distribution networks is proposed. The method requires only current measurements and is based on the analysis of the negative sequence components of the currents measured at secondary substations along medium voltage (MV) distribution feeders. The theory behind the proposed method is discussed in depth. The proposed method is examined by simulations, which are carried out for different types of networks. The results validate the effectiveness of the method in locating single-phase earth faults. In addition, some aspects of practical implementation are discussed. A brief comparative analysis is conducted between the behaviors of negative and zero sequence currents along a faulty feeder. The results reveal a considerably higher stability level of the negative sequence current over that of the zero sequence current.

Intermittent Earth Fault Passage Indication in Compensated Distribution Networks

“…Therefore, there is no need for synchronization of the measurements from various locations. In [13], a method based on the steady-state value of the negative sequence current at the fundamental frequency is proposed for locating permanent earth faults. It is based on a theoretical analysis of symmetrical sequence components, which shows that the negative sequence current at healthy feeders is insignificant.…”

“…The method presented in [13] is largely based on utilizing the negative sequence current's fundamental frequency, primarily developed for permanent faults. If it is used in its original form for intermittent earth fault location purposes, there will be a risk that the FPI device installed on the fault passage misses the fault.…”

“…If it is used in its original form for intermittent earth fault location purposes, there will be a risk that the FPI device installed on the fault passage misses the fault. The method presented in [13] and, in general, methods based on fundamental frequency quantities may fail to operate correctly when the measured quantities have significant transient characteristics or harmonics. Earth faults of the intermittent type normally have significant transient characteristics and harmonics and therefore problematic for fundamental frequency-based methods.…”

“…In this paper, the principles of a new FPI method to identify the faulted segment in compensated distribution networks are presented. The proposed method utilizes the concept introduced in [13], which is targeted for locating permanent earth faults but adapts it for intermittent earth faults.…”

Detection and Location of Earth Fault in MV Feeders Using Screen Earthing Current Measurements

“…Despite the presented method, harmonic based methods like Zon, Volna, ZVN, YC3, etc. or symmetrical component-based i.e., negative current are used [24,25].…”