Transformer partial discharge ultrasonic array detection method is a new method with high signal-to-noise ratio and high reliability.But the influence of array number to the direction finding accuracy needs to be further studied.Simulation of direction finding angle with the 15 kinds of sensor array（2×2-16×16arrangement）under two conditions of the acute azimuth and obtuse azimuth

study of change rule of direction finding accuracy of the different array number

for example of the square planar array sensor

based on an improved MUSIC（multiple signal classification）algorithm.The results show that the direction finding accuracy increases as the array number rises

and the specific error ranges of array sensors of different array number by simulating have some degree of guiding significance in the selection of transformer partial discharge ultrasonic array sensor in the field environment.