Abstract
An intermittent or restriking earth fault is a special type of earth fault that is common mostly in compensated cable networks. A great deal of effort has gone into protection against this type of fault. However, locating this fault has not received much attention. Therefore, there is a need to have a reliable method for locating this fault to repair the damaged cable. In this paper, the principles of a new method developed for locating transient intermittent earth faults on distribution networks are presented. The proposed method employs negative and zero sequence currents, and no voltage measurement is required, which means the proposed method has the potential to reduce cost when implemented in practice. It is intended mainly for typical intermittent earth faults in cable distribution networks where the typical fault resistance is in the range of a few ohms. Real data obtained from practical field tests is used to explain the phenomenon. A series of disturbance recordings obtained from field tests validate the proposed method.
Highlights
Uninterruptable power supply is essential in today's networks
The first intermittent earth fault occurs at 3 km from the HV/MV transformer on phase "a" The intermittent fault is simulated so that whenever the voltage exceeds a certain level, the cable's insulation level at the fault spot breaks down and the fault current starts to flow
Some degraded insulation level is given to start. This insulation level is compared with the instantaneous phase to ground voltage measured at the fault location
Summary
Uninterruptable power supply is essential in today's networks. Distribution system operators (DSOs) always try to improve their System Average Interruption Duration Index (SAIDI) using various solutions. In many countries, DSOs have started to replace overhead lines massively with underground cables in urban and rural areas [1]–[3] Despite the benefits this transition from overhead lines to cables provides, it brings about a new challenge to fault management systems, i.e., a special type of earth fault called an intermittent or restriking earth fault. These types of faults occur mainly in compensated cable networks. It can be characterized as a series of cable insulation breakdowns in which a sudden electric discharge to the ground occurs This type of fault is repetitive, and it ignites and self-extinguishes in irregular time intervals, which causes short current spikes. Because of these irregular current waveforms, conventional directional protection relays may fail to operate correctly
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
