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Partial discharge(PD) diagnosis and location is helpful to find the fault location of high-voltage power device in the early aging stage, and has important reference value for making maintenance plan. Now, many ultra high frequency (UHF) are often used to form sensor array, and three-dimensional coordinate system is defined to locate the partial discharge of transformer. In this paper, the principle of capturing the initial pulse of signal based on energy accumulation method and positioning based on time difference of arrival (TDOA) algorithm is studied. A nonlinear programming problem with the coordinates of partial discharge points as unknowns is constructed, and the tabu search particle swarm optimization (TS-PSO) algorithm is used to solve the optimal solution. The algorithm can avoid the problems of nonconvergence and nonuniqueness in solving nonlinear equations and the high initial value requirements of least square method. It can not only ensure the speed of solution, but also ensure the uniqueness and accuracy of solution. Laboratory and on-site tests verify the effectiveness of the positioning results.

With the acceleration of urbanization and the rapid development of industry and agriculture, fog-haze occurs frequently in most parts of China, which is a serious threat to the safe operation of the power system. The effects of fog-haze on the insulators represent in two aspects: a) increasing contamination on the surface of insulators and b) increasing the leakage current and decreasing the flashover voltage of insulators due to the wet deposition. Therefore, in this paper, naturally polluted insulators under fog-haze were taken as test objects, and the contamination and AC pollution flashover characteristics of different kinds of insulators were studied. According to the test results, contamination on the insulator surface is increased significantly under fog-haze in a short time. Compared with porcelain and glass insulator, the composite insulator shows more serious contamination under fog-haze environment. Saturated moisture time of two-shed type porcelain insulator is the shortest and saturated moisture leakage current of that is the largest, while composite insulator has the longest saturated moisture time and the smallest saturated moisture leakage current. Composite insulator is with the largest flashover voltage gradient, which is followed by bell type porcelain insulator and deep under-rib type glass insulator, and that of two-shed type porcelain insulator is the smallest among these insulators.