Impulse residual voltage test system for ZnO varistor

The Impulse Residual Voltage Test System for ZnO varistors is a specialized testing system used to evaluate the residual voltage characteristics of zinc oxide (ZnO) surge arresters (the core components of lightning arresters) under impulse currents such as lightning strikes or surge conditions.

Application

Impulse Current Test System can output 8/20μs standard lightning current, 4/10μs high current and 30/80μs switching current wave. The test system is used for carrying Residual Voltage Test, Pre-conditioning test and High Current Operating Duty Test.

Standards

IEC 60099-4

IEC60060

Technical Parameters

Features

Multi-waveform output capability:

The system is typically capable of generating not only standard lightning impulse current, but also, depending on configuration and testing standards, steep-front waves or rectangular long-duration waveforms to meet different levels of surge testing requirements.

High-precision dynamic measurement:

It adopts wide-bandwidth, high-accuracy non-inductive voltage dividers or Rogowski coils, together with high-resolution transient digital oscilloscopes, enabling precise capture of nanosecond-level response and peak residual voltage.

Impedance matching and low-inductance design:

The impulse generator circuit is designed with low inductance to minimize internal oscillations, ensuring that the output waveform complies with international and national standards such as IEC 60099-4.

Computer-based automated control:

Modern test systems are equipped with dedicated measurement and control software, featuring one-click automatic test report generation, waveform data analysis, automatic peak value extraction, and overvoltage protection functions.

Maintenance Information

Cleaning of high-voltage components:

Regularly clean the capacitor surfaces of the impulse generator, the discharge sphere gap, and the insulators using anhydrous ethanol to prevent dust accumulation that may cause surface tracking or flashover.

Maintenance of sphere gap electrodes:

Periodically inspect and polish the surface of the discharge sphere gap to remove oxidation layers caused by ablation, ensuring accurate and stable triggering discharge performance.

Inspection of oil-immersed/dry-type transformers:

Check the insulation oil level and overall condition of the test transformer and triggering transformer, ensuring there are no leaks and that the insulation performance meets required standards.

FAQ

1. What is impulse residual voltage?

Answer: Residual voltage refers to the peak voltage that appears across a varistor (or surge arrester) when an impulse current flows through it. Under specified current waveforms (such as 8/20 μs or 4/10 μs), measuring the residual voltage directly reflects the clamping protection level of the varistor under actual overvoltage conditions. lel.hk

2. What are the main components of the test system?

Answer: The core components typically include an impulse current generator (used to produce standard lightning and switching impulse current waveforms), a high-stability digital measurement and control console, a coaxial or non-inductive voltage divider, a high-capacity shunt (for accurate current measurement), as well as a dedicated oscilloscope and analysis software for high-frequency impulse signal acquisition and processing.

3. What standard test waveforms does the system support?

Answer: Depending on the test standards, the system is generally capable of generating standard lightning impulse current waveforms, steep-front impulse current waveforms, and slow-front switching impulse current waveforms.

4. Which international standards does the system comply with?

Answer: The design and testing procedures of the equipment strictly comply with International Electrotechnical Commission (IEC) standards, particularly IEC 60099-4 for high-voltage surge arresters, ensuring global accuracy and consistency of test data.

5. Besides residual voltage measurement, what other tests can the system perform?

Answer: Modern multifunctional residual voltage test systems can also perform high current operating duty tests and pre-conditioning tests. They are essential tools for varistor screening and aging tests.