Results of the study of the stabilization of the output voltage in transient processes when connecting the active load to the asynchronous generator

Abstract

Relevance: In recent years, many countries around the world have been paying special attention to energy resource conservation, the creation of new alternative energy sources, and the rational use of existing renewable energy sources (RES). Currently, according to the «2020 Key Performance Indicators Review for developed countries, the highest shares of renewable energy usage are observed in Sweden (60,1% of energy consumption), Finland (43,8%), and Latvia (42,1%). The primary sources of energy production in these countries include hydropower plants, wind power plants, and biomass processing» [1]. In this field, particular attention is paid to increasing the requirements for the structural simplicity of power sources for autonomous systems, ease of maintenance, relatively low weight (kVA/kg) and volume, as well as the stability of output parameters under operating conditions. The construction of alternating current generators primarily involves synchronous machines, phase-wound rotor asynchronous machines, and squirrel-cage asynchronous machines. In phase-wound rotor asynchronous machines, integrated frequency converters in the stator and rotor circuits enable effective control of the generator’s excitation process; however, additional external power sources are required for optimal operation control. In squirrel-cage asynchronous machines, the residual magnetization of the magnetic core allows the connection of capacitor banks to the stator windings, providing self-excitation of the generator and stabilization of the output voltage. This capacitor excitation scheme is decentralized, ensuring flexible operation modes of the generator unit under autonomous power supply conditions, which guarantees high efficiency and reliability in wind energy systems. In this article, based on the results of the conducted experiments, oscillograms reflecting the value of the output voltage in transient processes were obtained and analyzed for cases of connecting active loads of various values to an AG with a 4 kW short-circuited rotor.

Aim: stabilization of the output voltage in transient processes corresponding to the process of changing the active load of autonomously operating AG and analysis of the results.

Methods: methods for analyzing established and transient processes in electric power systems based on experiments were used.

Results: autonomous systems must meet requirements such as the simplicity of power supply design, ease of maintenance, relatively small mass (kVA/kg), and volume, as well as the stability of output parameters. Based on the analysis, appropriate proposals will be submitted for the use of AG in renewable energy sources.