Motor Load Protection of Electrical Systems From the Phase Failure in the Supply Network

Abstract

The results of mathematical modeling show that during phase failure in power supply systems with asynchronous and synchronous motors is appear power flows interchange between individual motors and the supply network, which makes it difficult to perform selective protection against exceeding the inverse sequence currents by known methods. Proposed protection on the supply input and on individual motors, based on the control of the current level of the inverse sequence and the absence of current in one of the phases. This protection on the supply input is also can used as start of fast-acting automatic transfer switch. The results of successful tests of protection are presented.