Development and Application of 110kV/60kVA Station Service Voltage Transformers

To address the challenge of providing construction power and station power for new energy power stations situated in remote areas, this paper presents the design of a 110kV/60kVA station service voltage transformer and accomplishes the setup of its protection and metering systems. Firstly, through electromagnetic calculations, an appropriate rated magnetic flux density of the core was selected, enabling the design of crucial parameters such as the core cross-sectional area and the number of winding turns. Secondly, by establishing an equivalent circuit model, the impact of supply winding load variations on measurement winding errors was analyzed. A method was proposed to dynamically compensate load errors using series impedance compensation. A Current Transformer for measuring the supply current and an impedance in series with the measurement winding were designed. Experimental verification indicated that when the load on the supply winding fluctuated between 0 to 60kVA, the measurement winding errors met the requirements for a Class 0.2 error limit. Ultimately, integrating protection and metering functionalities with the station service voltage transformer, a high-capacity, integrated power supply transformer was designed, effectively operating as a mini substation, it could supply power to remote area loads. The 110kV station service voltage transformer designed in this paper enables dynamic compensation for errors induced by supply loads. It also automatically disconnects the equipment in the event of a fault in the primary winding, while incorporating an energy metering function. This provides a reliable power source solution for remote regions.