More Accurate Reliability Estimation of Electric Devices Operated at Voltages Up to 1 kV

The paper studies the issues of efficiency of functioning of electrical switching devices at up to 1 kV, installed in industrial power supply networks. The service life of those devices is affected by the heating temperature of contacts and contact connections, loading factors, and ambient temperature. At present it is inexpedient to predict the reliability of devices based only on the statistical approach. It is necessary to combine the method of processing the data from the failures with the analysis of physical processes occurring in contacts and contact connections, causing aging, wear and subsequent failure of electrical equipment. Classification of the devices by the reliability level depending on the intensity of failures is proposed. The increase of the contact heating directly affects the distribution of failures. In order to increase reliability, failure rate estimation and correction factors were introduced. Those factors are taking into account the influence of the main factors of functioning. It is necessary to control the technical condition of low voltage electric devices, as well as to timely replace them before the first failures start to occur. The results of the work should be considered when planning the schedules for preventive maintenance in the power supply for industrial networks.