In high-voltage power systems, transformer insulation reliability plays a vital role in ensuring grid stability and operational safety. During operation, transformers may experience lightning strikes and other transient overvoltages, making insulation performance verification an essential step before equipment delivery.

A Lightning Impulse Generator (LIG), also known as an Impulse Voltage Generator (IVG), is a specialized high voltage testing system designed to simulate lightning impulse conditions and evaluate the insulation strength of transformers and other electrical equipment.

A Lightning Impulse Generator generates standardized high-voltage impulse waves to test the ability of electrical insulation systems to withstand sudden overvoltage stress.

It is commonly used for testing:

• Power transformers
• Instrument transformers (CT/PT)
• Bushings
• Insulators
• Surge arresters

The typical lightning impulse waveform is 1.2/50 μs, which simulates the characteristics of natural lightning surges according to international high voltage testing requirements.

The system is based on the Marx generator principle, featuring "parallel charging and series discharging".

Multiple capacitors are charged in parallel through a high-voltage DC source. When the preset voltage is reached, the spark gaps are triggered, connecting the stages in series to generate a high impulse voltage output.

Front resistors and tail resistors are used to adjust the waveform, ensuring the generated impulse voltage meets standard testing requirements.

For transformer manufacturers, lightning impulse testing is an important part of type testing and quality verification.

It helps to:

• Verify winding and insulation design
• Detect potential insulation weaknesses
• Improve transformer reliability
• Reduce the risk of failures during operation

Some insulation defects may not be detected by conventional power frequency tests but can be revealed under impulse voltage stress.

Lightning impulse tests are performed according to international standards, including:

• IEC 60060-1: High-voltage test techniques
• IEC 60076-3: Transformer insulation requirements

Meeting these standards helps transformer manufacturers provide reliable products for global power projects.

Sansion Power provides reliable Lightning Impulse Generator solutions for transformer manufacturers, power utilities, and high-voltage laboratories.

With accurate impulse waveform control and flexible testing configurations, our systems support insulation verification and help customers improve the reliability of high-voltage electrical equipment.

By simulating real lightning conditions, impulse testing builds a strong protection barrier for transformers and contributes to safer and more stable power systems.