When purchasing a zinc oxide arrester tester, how can one determine which type of solution better fits the actual needs of substation inspection and maintenance when faced with parameter descriptions such as "total current measurement," "resistive current measurement," and "harmonic analysis"? Differences in wiring methods, anti-interference capability, and data readability brought about by different measurement principles directly affect on-site judgment efficiency.
According to the DL/T 987 standard, the total current, resistive current, and harmonic components of a zinc oxide arrester under operating voltage are important indicators for judging insulation status. Among currently common test solutions, one type only measures DC reference voltage and 0.75 times leakage current, suitable for verifying valve element characteristics under power-off maintenance conditions; the other type adds total current and resistive current measurement under operating voltage on the basis of DC parameters, which can reflect insulation moisture and valve element aging trends, suitable for live-line inspection scenarios. From a procurement perspective, the latter places higher demands on current sampling accuracy and phase resolution capability, and attention should be paid to whether the instrument's separation algorithm is stable in harmonic environments.
Taking the YHX-9000 zinc oxide arrester tester as an example, its measurement objects cover DC parameters of zinc oxide arresters (varistors) and overvoltage protection components such as metal-ceramic two- and three-electrode discharge tubes. In live-line inspection and power-off maintenance of substations, this instrument can collect total current, resistive current, and harmonic components, helping to discover defects such as internal insulation moisture and valve element aging. Compared with solutions that only have DC parameter measurement, models that add current component measurement under operating voltage can provide more status information during the inspection phase, but during procurement it is necessary to verify whether the current sampling circuit has shielding and filtering design for the on-site electromagnetic environment, to avoid harmonic interference causing deviations in resistive current readings.
In selection comparison, attention should also be paid to whether the range and resolution match the voltage level of the arrester under test. There are obvious differences in total current amplitude between 10kV and below systems and higher voltage level arresters; if the instrument has insufficient range segmentation, the resolution capability for small current signals will decrease. In addition, the discharge tube test function can serve as a supplement to DC parameter measurement of overvoltage protection components; during procurement, it should be confirmed whether this function and the arrester test channel are independent, to avoid wiring switching affecting on-site efficiency. For teams whose main task is inspection, prioritizing the repeatability and anti-interference capability of current measurement under operating voltage is more practically meaningful than simply comparing DC parameter accuracy.
