What Is a Zinc Oxide Lightning Arrester Tester? What Problems Can It Identify?

Those who work in substation operation and maintenance know that lightning arresters are the first barrier for lightning protection in power systems. But what many people don't know is that zinc oxide arrester (MOA) will gradually age and become damp during long-term operation, and its protective ability will quietly decrease - and this change cannot be seen from its appearance. The zinc oxide lightning arrester tester is a tool specifically designed to "see through" this change.

Why do lightning arresters require specialized testing

The core of zinc oxide lightning arrester is the zinc oxide valve plate, which has extremely high nonlinear characteristics under normal conditions: under normal operating voltage, only a very small leakage current is allowed to pass through; Once overvoltage occurs, the valve plate quickly conducts, releasing the surge current into the ground to protect electrical equipment.

The problem is that after the valve plate ages or becomes damp, its nonlinear characteristics deteriorate, and the "resistive component" in the leakage current under normal operating voltage increases. The larger the resistive current, the greater the heat loss generated by the valve plate. Long term accumulation can lead to thermal collapse - lightning arresters can self damage or even explode without overvoltage.

What can the tester measure

HZ-20A can simultaneously measure: full current (Ix), resistive current (FHIR) and its peak value, capacitive current, fundamental power consumption (P1), 3rd/5th/7th harmonic components, and display voltage and current waveforms in real time.

Among these data, resistive current is the most critical indicator for determining the status of lightning arresters. Capacitive current mainly reflects the geometric structural characteristics of lightning arresters and is generally stable; Once there is a significant increase in resistive current, it is almost certain that the valve plate is aging or that there is water or moisture inside.

The value of live testing

HZ-20A supports testing under normal live operation of the lightning arrester without the need for power outage. This allows inspection work to be carried out without affecting power supply, significantly increasing the detection frequency and helping to detect problems in the early stages of lightning arrester degradation, rather than waiting until power outages for maintenance - which may have already caused losses.

Complies with the requirements of the power industry standard DL474.5-92 of the People's Republic of China.