Search

A practical relay algorithm for detecting High Impedance Fault (HIF) is proposed, in which an operational procedure in conjunction with a novel computational algorithm is proposed that has solved the problem of determination of HIF relay's settings, in order that both dependability and security are maintained. In addition, these settings can be tuned according to the changes in the feeder conditions, e.g. topology and load amounts. The discrimination is based on the existence, steadiness and randomness of harmonic energy content of the current waveform. The proposed algorithm is implemented on a DSP. Applying the data for HIF from field tests and for other similar phenomena from simulations has resulted in acceptable security and dependability for the proposed method., (2010 ISA. Published by Elsevier Ltd. All rights reserved.)

Locating high impedance fault (HIF) in a distribution network enhances the reliability of the system and improves the quality of the service for the customers. Due to low magnitudes of fault current and nonlinearity of fault impedance it is a very hard task and less considered by the distribution automation system. This paper introduces a novel method for estimating the location of high impedance arcing faults in radial distribution systems. The proposed method searches the feeders of the network at different locations, to find where the estimated parameters of the assumed HIF would result the most accurate estimation of the faulty phase voltage. The fault current and the arc parameters are estimated at each probable location employing an appropriate model to estimate the faulty phase voltage. As the proposed method uses the time domain analysis, it is applicable for nonhomogeneous distribution networks with unbalanced loading as well as symmetrical systems. The results of simulations of IEEE 34-node test feeder with various HIF parameters by EMTP-RV show that the proposed method is well capable of locating high impedance faults despite uncertainty in the load data. [ABSTRACT FROM AUTHOR]

In this paper, for the first time, a high-impedance fault indicator (HIFI), to be mounted on the poles of distribution feeders, is proposed to detect and track down the location of high-impedance faults (HIFs). The main contribution of this paper is the investigation of employing the magnetic-field strength signal, measured in the vicinity of the conductors of a feeder, to detect HIFs based on a novel pattern recognition method. The proposed HIFIs should be installed so that the faulted branch identification becomes possible and simple (i.e., at the sending ends of branches). Applying the data for HIFs, insulator leakage current and harmonic load from field tests and for other similar phenomena from simulations has shown high security and dependability of the proposed method as a computational model for HIFI. [ABSTRACT FROM AUTHOR]

This paper presents a reliable protection scheme for high impedance fault (HIF) detection in large and complex electrical distribution networks. The proposed algorithm uses dynamic features extracted by stationary wavelet transform and feeds them to a support vector machine-based decision making system. HIF occurrence is detected according to the normalized changes of the features extracted from three post-disturbance data windows. To provide more security, the output of the main fault classifier is compared with the outputs of three other classifiers in a voting system for final decision making. The results of simulations of a real distribution system demonstrate that the proposed scheme is able to detect a wide range of arcing faults, from a few amperes to hundreds of amperes, with high level of security against non-HIF phenomena. [ABSTRACT FROM AUTHOR]