Thermal Endurance of Cables by Connecting of Distributed Generation Objects to the Electric Power System

Abstract

By projecting of electrical annex of power plants not only the choice of the main electrical installations is conducted (e.g. generators, transformers, circuit-breakers), but also of cable lines. By checking of generator stator circuit cables for thermal endurance the thermal effect time is the short circuit clearance time by the operation of the main protective equipment and the current is the short circuit current from the electric power system or the generator. The goal of this paper is to adjust the cable choice method in a stator circuit of a low-power generator inbuilt in the existing nodes of the electrical power system as a distributed generation object. By thermal endurance check of stator circuit installations for such generators the short circuit reference point may be on the adjoined segment of the electrical grid. In this case, by electrically close short circuits and after their clearance without disconnection of the generator from the power grid an additional current rush and asynchronous operation current will increase the thermal generation. Recommendations for refinement of cable thermal endurance check method were developed for a gas turbine low-power generator, which operates parallel to the electric power system.