Criteria of creating a multi-level system of electrical equipment diagnostics, control and protection

Abstract

The reliability of the power electrical equipment (EE) of industrial enterprises, agriculture and medical institutions largely depends on the operating modes and power quality of the supply network. The existing methods of protecting EE, of an X-ray CT scanner, for example, act selectively and their actions are aimed at identifying and protecting electrical equipment from a certain type of a defect. This paper considers the criterion for creating a unified system of control, diagnostics and protection, which is – «EE + supply network» as a unified complex for controlling the switching modes of EE. The total volume of the system consists of five levels of protection types. The number of levels is determined by the type of EE and the magnitude of the possible estimated damage. The first level of protection is the diagnostics of the network state – the initial and subsequent continuous monitoring of the line voltages level and the rate of change of the front of the supply voltage first harmonic component. The second level is the diagnostics of the causes of the current-carrying lines breakage. The third level of protection is EE temperature protection and diagnostics of the thermal overloads causes. The third level is continuous monitoring of temperature indicators of EE. The fourth level is continuous monitoring of bolted connections temperature indicators. The fifth level is control of the insulation resistance value and diagnostics of the reasons for its decrease; moisture isolation protection; EE life prolongation, reliability and trouble-free work ensuring