When purchasing a zinc oxide surge arrester tester, faced with various models and parameter tables, which indicators truly affect on-site testing results? Some procurement personnel may focus on price or appearance while overlooking the core technical parameters that determine measurement accuracy. The following, from a practical application perspective, outlines several indicators that require key verification.
The measurement range and resolution of total current and resistive current are the primary concerns. The total current measurement range is typically 0~20mA, and the resistive current measurement range is also 0~20mA. Resolution determines whether early degradation trends can be identified. During procurement, one can confirm the instrument's resolving capability at full scale and check whether it supports range extension to accommodate arresters of different voltage levels.
The sampling method of the voltage reference signal directly affects the accuracy of resistive current decomposition. Common methods include PT secondary side wired synchronization, wireless synchronization, induction plate method, and voltage-free current analysis method. Wired synchronization offers higher precision but requires wiring, making it suitable for fixed-position testing; wireless synchronization can transmit over distances of several hundred meters or more, offering flexible operation; the induction plate method requires no wiring and is suitable for rapid patrol inspection. During procurement, the matching sampling method should be selected based on on-site conditions.
Three-phase simultaneous testing capability can significantly improve on-site efficiency. Instruments that support simultaneous acquisition of three-phase current and three-phase voltage with automatic compensation calculation can reduce repeated wiring and testing time, while also being compatible with single-phase or two-phase testing to adapt to different working habits.
Anti-interference capability and power supply method should not be overlooked either. The on-site electromagnetic environment is complex, and the instrument should have filtering or digital processing functions to ensure stable data. For the power supply method, attention can be paid to battery life and charging convenience to avoid work interruption due to power depletion.
In addition, it is recommended to verify whether functions such as resistive current harmonic analysis, power-frequency reference voltage measurement, active power and phase difference display are provided, as these parameters help to more comprehensively evaluate the arrester's condition.
