To address the issues of electromagnetic interference around power frequency transformers in solar photovoltaic power grid connection

as well as complex signal analysis caused by multiple discharge sources discharging simultaneously or alternately

and difficulty in locating partial discharges

a method for locating partial discharges in power frequency transformers in solar photovoltaic power grid connection is studied to improve the effectiveness of partial discharge localization. Based on the analysis of the structure of the solar photovoltaic grid connected power generation system

determine the key components and monitoring point locations. Using ultrasonic sensors to capture the ultrasonic signals generated by partial discharge in power frequency transformers

and based on the time difference positioning method

utilizing the time delay difference between ultrasonic signals to locate the location of partial discharge; considering that the overdetermined equation system used in the time difference localization method is difficult to obtain an accurate solution for the location of partial discharge

the time difference localization method is transformed into an optimization problem for the location of partial discharge. The objective function is to minimize the time difference

and the nonlinearity of partial discharge localization is considered. The firefly algorithm is used to obtain an accurate solution for partial discharge localization that minimizes the time difference. The test results show that this method has a maximum positioning error of 0.05 cm and a positioning time of about 0.3 s for the partial discharge position of the power frequency transformer in the grid connected solar photovoltaic power generation. It has good positioning effect and high positioning efficiency.