For 10KV high-voltage switchgear, the voltage for withstand voltage test needs to be raised to 42KV. IEC 61439 is a standard developed by the International Electrotechnical Commission (IEC) that covers design verification for low-voltage electrical products and assemblies. The IEC 61439. The busbar withstand voltage test, performed by Wuhan Musen, verifies the busbar's insulation strength and withstand voltage, ensuring the safety and reliability of this critical emergency power supply equipment during power repairs and temporary power supply operations. Relay Protection Maloperation: Recalibrate protection settings, repair CT secondary circuits, and stabilize the control power supply. Preventive Maintenance Measures. A properly conducted busbar stability test ensures that busbars can withstand short-circuit forces, thermal stress, and operational loads without deformation or failure.