Study on the Influence of Temperature on Tanδ Measurement of 110kV Cascade Voltage Transformer

Cascade voltage transformers (hereinafter referred to as CTV) are widely used in power grids, and a good insulation condition is a prerequisite for their safe and reliable operation. 110kV CTV tan δ can be affected by changes in environmental factors (such as temperature and humidity), and sometimes the tanδ can be abnormal or even fail to reflect the actual state of the equipment. This paper takes a JCC6-110 CTV which has been operated for many years as the research object, and makes a comprehensive and detailed study on the influence of temperature on CTV tanδ, and researches the change of CTV tanδ under different temperature conditions, proposes the CTV insulation equivalent circuit model, obtains tanδ and capacity data through different wiring methods and derives the model parameters, and establishes the insulation equivalent circuit model influenced by temperature factors. The insulation equivalent circuit model with the influence of temperature factors is proposed, and the method of correcting tanδ to the standard atmospheric conditions is proposed. The model was simulated using MATLAB/Simulink software to verify the correctness of the insulation equivalent circuit model considering the effect of temperature on tanδ under fault conditions, and the model can be applied to the conversion and correction of the effect of temperature on CTV tanδ during field testing.