Improvement in High Impedance Fault Detection of Primary Distribution Network Using Voltage and Current Sequence Components

An increasing number of fire and electric shock accidents in power sector increases the need for high impedance fault (HIF) detection as the existing over-current relay in the system is not able to detect the HIF state. The HIF detector employing sequence components of current along with voltage is proposed in this paper. The proposed HIF detector composed of two components i.e. current HIF detector and voltage HIF detector, in conjunction with existing distribution network set up. The first component analyzes current sequence components when fault appears in the network whereas later analyzes voltage sequence components. The current HIF detector operates when, significant amount of zero and negative sequence components starts appearing in the network. On the other hand, voltage HIF detector assists the current HIF detector in confirming the HIF state by examining the negative voltage sequence component. The performance of combined detector is evaluated by inducing high impedance fault at different nodes on the IEEE-6-bus radial balanced distribution system. The proposed detector makes use of only current and voltage of the system for HIF detection and doesn't require any additional feature extraction phase. The HIF detector in the proposed paper requires only one unit of sequence converter. Now, sequence components coming out from sequence converter are fed to HIF relay logic which is used in conjunction with existing over-current relay. Hence, this detector is cost effective as compared with the different HIF detectors presented in literature. The proposed method is simulated in a simulation environment. This method is fast and reliable as it detects the fault within one cycle.