Experience in using devices for voltage control under load in working transformers for in-house needs of energy generating units

During design of the electrical portion of an energy unit for thermal power plants and nuclear power plants, the feed circuit for in-house needs in domestic practice uses transformers equipped with devices for voltage control under load (VCL). It is felt that the need to use VCL devices in working transformers for in-house needs is obvious and no special justification is required for it. This circumstance is the reason behind the absence in All-Union State Standard 11920-73 of PBV transformers for power plant in-house needs. The use of VCL devices in working in-house transformers greatly reduces the reliability of operation and that of the energy unit as a whole. From the conditions of economics, reliability and ensuring the required voltage levels on the 6 kV lines the use of VCL devices in working in-house transformers is ill-advised. A need has arisen for enterprises of the Ministry of Electrical Engineering of the USSR to adapt PBV transformers for use as working transformers for in-house purposes in power plants. In individual cases the use of VCL transformers is not precluded in the presence of engineering and economic justifications during the design state, but operation of the VCL must be carried out inmore » the automatic mode.« less