Influence countermeasures of two-color infrared thermometer
Whether the fault of electrical equipment is a heating fault caused by current effect (conductive circuit fault), the heating power is proportional to the square of the load current value. Heating failure caused by voltage effect (insulation medium failure), 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 results of infrared detection and fault diagnosis. The increase in leakage current can cause uneven voltage in parts of high-voltage equipment. If there is no load operation or the load is very low, the heating of the equipment failure will not be obvious. Even if there is a serious failure, it will not be exposed in the form of characteristic thermal anomalies. Only when the equipment is operating at rated voltage and the load is greater, the heat generation and temperature rise will become more serious, and the characteristic thermal anomalies at the fault point will become more obvious. Therefore, when performing infrared detection, in order to obtain reliable detection results, it is necessary to try to ensure that the equipment operates at rated voltage and full load. Even if continuous full load operation is not possible, an operation plan should be prepared to facilitate the detection before and after the detection. During the process, the equipment can be run at full load for a period of time (such as 4 to 6 hours), so that the faulty part of the equipment has enough time to heat up and ensure that its surface reaches a stable temperature rise.
Since in infrared diagnosis of electrical equipment faults, the fault judgment standard is often based on the temperature rise of the equipment at rated current. Therefore, when the actual operating current during detection is less than the rated current, the temperature rise of the equipment fault point actually measured on site should be converted to Temperature rise of rated current.
