This paper presents a method for locating multiple partial discharge (PD) sources based on maximum a posteriori (MAP) estimation. The sensors placed in the monitoring area, such as a substation, receive PD signals and estimate the direction of the arrival angles by using estimation of signal parameters via rotational invariance techniques. Then the sensors send the measurement data to the processing unit which integrates these and the prior distribution of the PD source to locate the PD sources. The capability of the proposed system is confirmed by numerical simulations using the finite‐difference time‐domain method. The simulation results include the comparison of performance for various number of sensors. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.