Research on Rolling Forecast Method of Short-Term Dynamic Thermal Rating of Oil-immersed Power Transformer

Carrying out a dynamic transformer rating assessment to enhance the utilization rate of the transformer is the development direction of lean asset management. This paper proposes a short-term dynamic thermal forecasting method for transformers by considering the insufficiency of the heat dissipation boundary conditions. Firstly, the transformer hot spot temperature is divided into the thermal temperature rise of load and the temperature rise due to the surrounding environment, and the first-order thermal circuit model is established, respectively. The dynamic thermal rating forecasting formula is obtained, and the thermal parameters of the models are also identified by considering the transient profiles of hot spot temperatures. On this basis, the surrounding environment temperature forecasting model is established based on the boundary condition equivalence principle and combined with the time series analytical method. Finally, the surrounding environment temperature profiles in summer and winter are used as input to evaluate the dynamic thermal rating of the transformer and realize a short-term rolling forecast of the dynamic thermal rating of the transformer.