Electrical equipment faults, whether caused by current effects or conductive circuit faults, have a heating power proportional to the square of the load current value. Heating faults caused by voltage effects (insulation medium faults), where the heating power is proportional to the square of the operating voltage. Therefore, the operating voltage and load current of the equipment will directly affect the effectiveness of infrared detection and fault diagnosis. The increase in leakage current can cause uneven voltage in some high-voltage equipment parts. If there is no load operation or the load is very low, it will make the equipment malfunction heating less obvious, and even if there is a more serious malfunction, it is impossible to be exposed in the form of characteristic thermal anomalies. Only when the equipment is operating at rated voltage and the load is higher, the heating and temperature rise become more severe, and the characteristic thermal anomalies at the fault point are also exposed more clearly. Therefore, when conducting infrared detection, in order to achieve reliable detection results, it is necessary to ensure that the equipment operates at rated voltage and full load as much as possible. Even if continuous full load operation cannot be achieved, an operation plan should be developed to allow the equipment to run at full load for a period of time (such as 4-6 hours) before and during the detection process, so that the faulty part of the equipment has sufficient heating time, and ensure that its surface reaches a stable temperature rise.