Reasonable Setting of the Leakage Protection Actuating Value of Feeder Switches for Mine

When selectivity leakage protection of underground power supply systems are used,the feeder switches have often change leakage actuation values,especially in as branch switches,most of them can change their leakage actuation values.Some values have become smaller than national standard and industry standard,which have safe hidden peril.The paper analyzes the key reasons whcih lead to the leakage actuation values changing and how to reform to select the vacuum feeder switch with leakage protection.