Impulse Current Test System

An Impulse Current Test System (Impulse Current Generator) is an electrical testing device specially designed to simulate transient high-energy overcurrent phenomena such as lightning strikes, large equipment switching operations, or power grid faults. It is mainly used to evaluate the insulation performance, residual voltage characteristics, and damage resistance capability of electrical equipment and components when subjected to high-current impulses.

Applications

ICTS MOA 8/20&4/10 Impulse Current Test System can output 8/20μs standard lightning current and 4/10μs high current wave. The test system is used to carry Residual Voltage Test for MOA of 110kV power system and below.

Standards

IEC60099-4.

IEC60060

Technical Parameters

Features

High Energy and Strong Current Output: Capable of generating extremely high peak currents up to tens or even hundreds of kA (for example, waveform amplitudes exceeding several hundred kA), thereby simulating high-energy electromagnetic transients.

Extensive Waveform Generation Capability: Able to generate various standard waveforms in accordance with the latest international standards (such as IEC and IEEE), including lightning impulse waveforms, switching impulse waveforms, steep current impulses, and rectangular waves.

Multi-Stage Discharge and Series-Parallel Architecture: Commonly based on the Marx generator principle, in which multiple capacitors are first charged in parallel and then discharged in series to achieve extremely high instantaneous power output.

Extremely Low Stray Inductance: Incorporates optimized circuit layouts and non-inductive wound resistors to ensure minimal internal inductance within the circuit, thereby enabling the generation of very steep pulse front times (such as within a few microseconds).

Maintenance Information

Discharge Sphere Gap Inspection: Regularly clean the metal oxides generated by discharge sparks, inspect the erosion condition of the sphere surfaces, and re-polish or recalibrate the sphere gap spacing when necessary.

Pulse Capacitor Maintenance: Check the capacitors for visible swelling or oil leakage, measure their capacitance and dielectric loss, and tighten the high-voltage connection terminals.

Grounding System Verification: Since impulse current systems generate extremely strong transient currents, maintenance procedures particularly emphasize ensuring that the system adopts a low-impedance, single-point star grounding configuration to protect both operators and equipment.

FAQ

1. What are the main application fields of an Impulse Current Test System?

This system is mainly used to evaluate the insulation integrity and high-current impulse withstand capability of power transmission, power distribution, and electronic electrical equipment. Typical test objects include surge arresters, surge protective devices (SPDs), transformer windings, grounding devices, cables, and various types of high-voltage switchgear.

2. What standard waveforms can the system generate?

According to different international standards, the system can generate various typical current waveforms:

Exponential waveforms (such as 8/20 μs or 10/350 μs): used to simulate lightning surge currents.

Rectangular wave currents (such as 2 ms rectangular waves or long-duration current waveforms): used to simulate long-duration system transient processes.

3. How does an impulse current generator produce extremely large currents?

Its basic operating principle is to use a high-voltage charging device to charge a bank of high-voltage capacitors, and then instantaneously discharge the stored energy through a special triggering switch (such as a discharge gap or thyristor switch). Through specifically designed resistors and inductors (wave-shaping circuits), the enormous energy is concentrated and released onto the test specimen.

4. How are extremely large currents and voltages accurately measured during testing?

To prevent high voltage and large current from damaging measuring instruments while ensuring measurement accuracy, the system is equipped with dedicated shunts or Rogowski coils for current signal acquisition, as well as non-inductive voltage dividers for residual voltage measurement. These signals are transmitted to digital transient recorders with strong electromagnetic interference (EMI) immunity, such as oscilloscopes or transient recording systems specifically designed for high-voltage testing.

5. How is it determined whether the tested equipment has passed the impulse test?

Engineers compare the condition and electrical characteristics of the equipment before and after testing. The evaluation criteria generally include:

Visual Inspection: No burning, cracking, explosion, or obvious physical damage on the sample surface.

Electrical Parameter Comparison: Whether changes in varistor voltage (for MOV devices), leakage current, or insulation resistance before and after the impulse application remain within the allowable tolerance range.

Waveform Analysis: Comparison between the theoretical standard waveform specified by the standard and the actual recorded voltage and current waveforms to determine whether abnormal waveform distortion has occurred.