Signal injection techniques for fault location in distribution networks

Abstract

Abstract. Over the last 50 years, fault location in transmission systems has been a subject of interest to utility engineers and researchers. Nevertheless, it has not been until the last decades that fault location in distribution networks has started to gain prominence.Traditionally, fault location techniques for distribution networks have been classified in three different groups: fundamental frequency measurements, high frequency measurements and the use of artificial intelligence (AI). Yet despite this rigid classification, a new approach has started to be developed over the last years based on the injection of a discernible signal into the distribution systems, mainly in non-effectively grounded networks. However, even when recent developments of new grounding systems reinforce the possibility of using this kind of techniques, these are not usually cited by general reviews and overviews of fault location systems in distribution networks. Accordingly, this paper aims to provide a general but clear overview on the existing techniques for fault location in distribution networks based on signal injection. Apart from describing the different options presented to date, the most important aspects that characterize them and the injected signal are briefly outlined, as well as a comparative performance analysis.

Validation of a PMU‐based fault location identification method for smart distribution network with photovoltaics using real‐time data

“…These methods rely on time synchronisation and advanced digital signal processing and can lead to errors if the output signal is too noisy. Another method, known as signal injection technique, is based on injecting a particular frequency signal in the circuit and expects it to return to earth along the fault line [17]. The fault line is located by identifying the section where the signal flows through.…”

Faults Monitoring System in the Electric Power Grid with Scalability to Detect Natural/Environmental Catastrophes

“…In data transmission networks, it is required a minimum of 9.2 Kbits/s information transport capacity, i.e., a lower bandwidth but a high communication security level. For this work, the GSM (Global System for Mobile Communications) mobile network at 19.2 Kbits/s was chosen to send data to the dispatch center of the electrical grid [2]. The general scheme of the faults monitoring system is given in Fig.…”

“…Another problem that exists is that in small grids, typically there is no automatic protection device along the feeder. In this area, several authors have performed different approaches for create an efficient monitoring system for the detection and location of the faults in electric power grid:  Based on the signal injection method to localize the fault point, using detectors along the feeder creating the fault information vector with injected signal and zero sequence current [2] [3];  Method to estimate an approximate state of the electrical grid (power flow) from measurements of voltage magnitude and phase angle at a small number of lines [4] [5];  To detect and locate failures, observing the behavioral of the three power lines phases over time, using tools as Hilbert transform and fuzzy classifier to successful detection [6];  Method to detect and classify faults in transmission line using ANN (Artificial neural networks), using as input samples of the current and voltage, the detector is constructed by four different ANN corresponding one of each phase and one for the earth [7];  Some failures are related with atmosphere conditions, so it is necessary to design environmental parameters monitoring device for transmission lines in real time [8] [9]. This work develops a system that assists in the detection of fault location with a high accuracy and can monitor faults in real time connecting through a telecommunications network, a system responsible for managing the electric power grid.…”

Evaluation of earth fault location algorithm in medium voltage distribution network with correction technique

“…Another researcher [7], studies about high-impedance faults (HIFs) which produce a small fault current, thus not detectable by some overcurrent protection devices. To solve that problem, the researcher analyzed the data by converting the harmonic analysis of current waveforms in the MATLAB by using Fourier transform.…”

“…According to [7], fault location techniques for distribution networks have been classified into three different groups: fundamental frequency measurements, high-frequency measurements and the use of artificial intelligence (AI). Referring to [9], the short-circuit fault, reliable earth fault indicators are lacking, and the fault distance computation is still an open issue for utilities.…”