Accurate on-line fault location and PD activity location results obtained with SCG – a long-term utility experience

Abstract

In recent years, Alliander (one of the largest network owners in the Netherlands with almost 40,000 km of medium-voltage (MV) cable (polymer insulated lead covered and cross-linked polyethylene) installed a number of smart cable guard (SCG) systems to verify its effectiveness in preventing failures or, if there is a breakdown, to reduce the repair time (outage time). Alliander concluded that SCG is indeed a very effective tool for on-line detection and location of (intermittent) faults and partial discharges in MV power cables. These phenomena are located with an inaccuracy better than 1%, based on travelling waves. On average, each SCG system could have prevented about 6150 customer minutes lost per year. Preventive repair also allows seeing the cause of degradation, helping to develop counter measures. SCG can be used in all types of MV cable networks and replaces fault passage indicators as well. Based on this, Alliander will implement more SCG systems in the upcoming years.