ANALYSIS OF EXISTING ROTECTION FROM GROUND FAULTS IN 6-10 KV VOLTAGE NETWORKS

Abstract

One of the components of any electrical complex is the distribution networks with voltage 6-10 kV, which operate in Kazakhstan with isolated or compensated neutral. Research results show that the main cause of severe accidents in these networks is often due to incorrect actions of relay protection during single-phase ground faults, which make up to 90% of all electrical damages. The resulting interruptions in power supply, even for a short period, can lead to prolonged disruptions in technological processes at enterprises. In some cases, the cause of accidents can be single or group false trips of relay protection devices during ferroresonance processes. Inadequate sensitivity to single-phase faults, when they transition to multi-phase short circuits, can also result in significant power outages and losses due to failure of relay protection. Therefore, it is considered necessary to equip 6-10 kV networks with protection against ground faults that have sufficient selectivity and sensitivity to stable short circuits, including through an arc-quenching reactor, repeat action, and the ability to detect individual self-clearing insulation breakdowns. Numerous attempts to create selective protection against ground faults in networks with compensation for capacitive current that satisfy most of the requirements for its properties have not yet resulted in the creation of a suitable device. In some cases, protection in networks with isolated neutral (for example, during ferroresonance processes) may also fail to meet the requirements. Therefore, the development of more advanced protection against single-phase ground faults that can meet all requirements in networks with isolated or compensated neutral as well as in networks grounded through an arc-quenching reactor remains relevant. This article discusses the current protection against ground faults in 6-10 kV networks.