To calculate the probability factor for location coincidence, which is one of the factors used in calculating the limit for protecting a wireless system from electromagnetic disturbance, we first propose average distance calculation models between a disturbance source and a victim receiver. Next, the propagation characteristic of the electromagnetic field from WPT system for EV on the natural ground plane is calculated by the moment method to obtain the propagation coefficient at 150 kHz-30 MHz and 1–100 m. Finally, from these results, the probability factor for location coincidence of the WPT system and some communication systems are estimated.