As power grids modernize, ensuring reliable substation operation grows increasingly critical. Uncrewed aerial vehicle (UAV) inspections provide significant advantages over traditional manual and robotic methods, such as cost-effectiveness, greater maneuverability, improved efficiency, and the ability to operate in closer proximity to equipment. However, the complex electromagnetic-field environment within substations poses challenges for UAV operations. Determining a safe distance between UAVs and high-voltage equipment is essential for deploying UAVs effectively in substation inspections. This study investigates electromagnetic field exposure during UAV-based substation inspections. A computational model was developed to evaluate the electromagnetic field and simulate the surface field distribution during UAV operation. The results indicate that the UAV is affected by strong electromagnetic fields near the four rotor blades and the central wing section. Laboratory high-voltage tests, combined with simulations, confirmed that the UAV can perform inspections while maintaining a 50 cm distance from high-voltage equipment. Furthermore, when the UAV approaches the equipment to the point of gap discharge, it can continue operating normally for a limited time, demonstrating its certain ability to withstand high-voltage electric fields. These findings provide critical insights for establishing safe operating distances for UAVs in substations.