Operation of electric networks

Maintenance and fixed-schedule preventive operations ensure reliable functioning of the power-supply system.
Daily maintenance is a set of activities directed at maintaining the serviceability of the power-supply system and its preset operating parameters. Maintenance includes the following work package:

• keeping account of the electric power consumed and associated reporting;
• servicing of power-supply systems in compliance with the requirements of normative operation rules;
• provision of around-the-clock supervision of functioning of the premises" electric equipment in order to detect any disturbances in its operation in time and to prevent emergency situations;
• removal of emergency situations and restoration of the normal power consumption mode;
• repair of insulation, laying of cables;
• wiping of light bulbs, replacement of blown bulbs;
• elimination of minor failures in electric wiring;
• replacement of plug sockets and switches;
• connection and disconnection of cables;
• repair of magnetic starters, start buttons, circuit-breakers, toggle switches, rheostats, contactors, and other similar starting and switching devices on condition that they are mounted outside switchboards and assemblies;
• repair of free-standing magnetic stations and control units;
• removal and mounting of electricity supply meters, other instruments and measuring equipment;
• replacement of fuses and repair of lighting wiring and fixtures;
• mounting of additional electric outlets and connecting them to the mains upon request;
• providing supervision of the contractor during the entire time of his work in the switchboard rooms.

Scheduled preventive operations (SPO):

• cleaning of installed equipment and insulator bushings from dust and dirt;
• drainage of moisture and sediment accumulated in expansion tanks;
• sampling of transformer oil for subsequent analysis;
• oil filling-up;
• visual inspection of work conditions and protective grounding;
• checking of insulation resistance of windings and insulator bushings;
• switching of output voltage steps (if necessary) – with disconnection of the transformer from the mains;
• checking the reliability of contact connections and fastening joints;
• inspection of the condition of switchboard instrumentation and alarm devices;
• inspection of the condition of working contacts;
• cleaning and adjustment of circuit-breaker contacts;
• conformity checks of ratings of mounted circuit-breakers to the load of circuits protected;
• testing of operation of circuit-breaker electric drives;
• inspection of busbars and cable conductors for absence sparking, crackling or local heating, traces of soot or metal melting;
• visual inspection of the condition of grounding devices;
• inspection of the condition of cable terminations;
• testing of insulation resistance of current-carrying parts;
• check of the availability and condition of protective guards, placards, preventive inscriptions and marking on panels and communication devices;
• check of the serviceability of locks and door seals;
• measurement of impedance of phase-neutral loop;