Production sites that require increased reliability of energy supply should be protected from power supply interruptions, since an emergency shutdown of the power supply can lead to danger to people’s lives, a threat to the security of the state, disruption of a complex technological process and significant material damage. The purpose of the study is to create a backup power supply system for an enterprise, using emergency and uninterrupted power supply sources, such as built-in batteries, uninterruptible power supplies, diesel generator stations, on the example of an oil refinery. In the event of an emergency, the sources used in a short time must ensure the normal operation of critical facilities (boiler house, water intake, computer system, fire extinguishing system, etc.) from backup power sources. Materials and methods of research. When developing a technical solution for the power supply of an industrial enterprise, the authors were guided by the regulatory documents. The COMPASS software product was used in the construction of the schemes. Results. The paper presents the power supply system of an oil refinery with the possibility of using a diesel generator station as a trouble-free power source. Diesel generator stations fully meet the reliability requirements for emergency maintenance of the network for more than 24 hours. To ensure uninterrupted power supply to consumers of a special group of the first category, inverter-battery systems are proposed as autonomous power sources. An algorithm to provide backup power supply has been developed as a technical solution of practical interest in the design of power supply schemes for responsible groups of electrical receivers. The organization of automatic input of the reserve in case of power outages from the main inputs is presented. Conclusions. The considered system of power supply from independent power sources using diesel generator sets and uninterruptible power supplies in combination with devices for automatic switching on of backup power makes it possible to increase the reliability of power supply to responsible consumers and prevent emergencies associated with power outages.

Electrical machines are widely used in various branches of the national economy. In particular, electric motors are one of the main elements in electrical power generation systems. The electric machines used at this ensure reliable operation of individual power units and the entire power supply system in general. The reliability of engines’ operation is largely determined by the quality of its insulation, that is why the improvement of methods for controlling the isolation of high voltage asynchronous motors is an actual task. The aim of the research is to develop a method of continuous automated control of electric insulation condition in stator windings of an asynchronous motor basing on the analysis of experimental and industrial operation data making it possible to estimate the dynamics of changes in the main insulation parameters. The main elements showing reliability of high-voltage electric machines, applied electro-insulation structures, methods for controlling insulation resistance in a high-voltage electric motor are considered in the article. The research performed was based on the results of the experimental and industrial operation of the automated system of insulation control under working voltage at the real facility carried out by the group of companies «Energopribor» of the town of Cheboksary. The analysis of existing methods for insulation control is given, the scheme of insulation control by superpositioning test current with the frequency which is different from industrial one. The authors propose the method to estimate the dynamics of resistance changes in insulation of stator windings of the asynchronous motor, to reveal its approximation to the maximum permissible state in the process of operation and in reserve shutdown. Software modeling was carried out, the results of which correspond to the data of experimental and industrial operation. The results obtained during the research allowed to systematize the obtained experimental data, to modernize the hardware part of the diagnostic complex DUKAT-SCAD, to outline the criteria area for its applicability.