The Probabilistic Assessment of Outgoing Transformer Operation Risk Considering the Correlation Between Wind Power and Photovoltaic

In order to evaluate the impact of wind farm and photovoltaic power station on the operation risk of outgoing transformer, this paper puts forward probabilistic assessment of outgoing transformer operation risk considering the correlation between wind power and photovoltaic, which takes into account the randomness and correlation between wind power and photovoltaic. According to the measured output of wind-solar complementary power station, kernel density estimation is adopted to fit the probability density distribution of wind farm output as well as photovoltaic power station output. The joint probability density distribution of wind power and photovoltaic is established using Copula theory, and Kendall rank correlation coefficient is used to measure the degree of correlation between wind power and photovoltaic. For the assessment of outgoing transformer operation risk, the characteristic temperature of transformer is calculated based on Susa model. In addition, this paper proposes evaluation indexes including insulation deterioration probability (IDP), insulation failure probability (IFP), and expected loss of insulation life (ELOIL). Afterwards, the assessment of outgoing transformer operation risk is completed by Monte Carlo method. Finally, the wind-solar complementary power station located in Qinghai province is chosen as case study and it verifies the effectiveness of proposed method. Moreover, the results can provide guidance for the selection and operation of outgoing transformer.