Calculation of the Capacity for the Operation of a Mini-Energy Complex Based on an Inde-pendently Operating Asynchronous Generator

Abstract

The article present the analysis of the operation of the mini-energy complex (MEC) based on alternative energy sources. An asynchronous generator (AG) was taken as energy source. The IEC operates independently with standard power parameters without the use of a frequency converter. To operate independently, AG needs a source of reactive excitation current. Based on the calculations carried out and the results obtained with the use of the experimental facility,the operating conditions of the MEC with standard parameters of electricity under varying load have been analyzed. A characteristic feature of the autonomous MEC is the commensurate capacity of the generating device and consumers. Therefore, any power consumer on/off leads both to significant changes of local electric system parameters and affects the operation of the generator itself. In this article, the main attention is paid to the influence of three-phase motor load on stable AG operation. When the MEC operates independently, reliable self-excitation of the asynchronous generator and the start-up of consumers whose power is commensurate with the generating unit must be ensured. It is also necessary to ensure the maintenance of voltage stability, the possibility of automatic operation of the generating unit, and the preservation of its integrity in emergency modes. Thus, for stable MEC-based AG operation the nature of the load should be taken take into account, the parameters of the of the local grid should be known as well as the exact availability of consumers and their characteristics, and also equivalent circuit parameters of asynchronous motors. In addition, it is necessary to accurately calculate the capacity when changing the parameters of the electrical system, so as not to lose the self-excitation of the asynchronous generator, which is equivalent to disconnecting the entire load of the generator and causes a sharp increase in speed. To solve these problems, it is necessary to create a high-speed MEC control system.

Keywords

• mini-energy
• alternative energy sources
• generating device
• magnetic current
• self-excitation of an asynchronous generator
• three-phase motor load
• equivalent circuit