Recently, the Sansion Power engineering team was urgently deployed to a customer's 220kV substation to carry out GIS withstand voltage testing and partial discharge (PD) testing.

Despite challenging site conditions and a very limited testing window before rainfall, the team successfully completed the required tests and helped ensure that the project could proceed toward on-time energization and acceptance.

The testing was carried out under demanding environmental conditions, including high temperature, high humidity and approaching rain.

Moisture had accumulated on the surface of the GIS enclosure and insulators, creating significant leakage-current interference. At the same time, strong electromagnetic noise was present inside the substation, while the test circuit extended for several hundred meters.

These factors significantly reduced the effective testing window and increased the difficulty of obtaining stable and reliable test data.

For high-voltage GIS testing, environmental interference can have a direct impact on test stability and partial discharge measurement sensitivity.

This is where the performance of the testing equipment and the experience of the engineering team become critical.

For this project, Sansion Power used the SXPD Partial Discharge-Free Variable Frequency Series Resonant Test System, a high-voltage AC test solution designed for demanding electrical testing applications.

The system can be used for AC withstand voltage testing of a wide range of high-voltage equipment, including:

• Power transformers
• Instrument transformers
• Power cables
• GIS / gas-insulated switchgear
• Circuit breakers
• Other high-voltage electrical equipment

It can also support induced withstand voltage and partial discharge testing of transformers, as well as power-frequency withstand testing for large generator units and 220kV substations.

This versatility allows one test system to address a wide range of high-voltage laboratory and field-testing requirements.

In this 220kV GIS project, environmental and electromagnetic interference were among the biggest challenges.

The SXPD system features strong anti-interference performance and is equipped with a high-precision partial discharge measurement unit.

This enabled the engineering team to effectively monitor partial discharge activity and identify potential small insulation defects in critical GIS components, including:

• GIS busbars
• Insulating components
• Epoxy insulators
• Post and basin-type insulators
• Other GIS insulation structures

The system supported simultaneous withstand voltage assessment and partial discharge monitoring, providing reliable test data even under challenging field conditions.

With the weather window rapidly closing, every minute on site mattered.

Sansion Power's engineering team coordinated the test sequence carefully, optimized the testing process and made full use of the available working time.

Thanks to the combination of:

Reliable test equipment + professional engineering team + practical field experience

the 220kV GIS withstand voltage and partial discharge tests were successfully completed before the rain, passed acceptance requirements on the first attempt and helped keep the project on schedule for energization.

Sansion Power has been deeply involved in the power testing and high-voltage testing industry for more than 20 years.

Our strength comes from an integrated approach built around:

We provide our own high-voltage testing equipment, allowing us to select and configure the right solution according to actual project requirements.

Experienced engineers handle on-site testing, commissioning and troubleshooting without relying on temporary external teams.

From equipment configuration to field testing and data analysis, our technical capabilities cover the complete testing process.

No outsourced testing. No unnecessary middle steps.

This integrated model allows Sansion Power to respond quickly to complex site conditions and maintain better control over testing quality, safety and project schedules.

The successful completion of this 220kV GIS testing project demonstrates that high-voltage testing does not stop when site conditions become difficult.

For substations facing high humidity, electromagnetic interference, long test circuits, tight construction schedules or approaching adverse weather, the combination of reliable testing equipment and experienced engineers can make a critical difference.

Sansion Power is committed to providing professional solutions for:

• GIS AC Withstand Voltage Testing
• GIS Partial Discharge Testing
• 220kV Substation Testing
• Variable Frequency Resonant Testing
• High-Voltage AC Withstand Testing
• Transformer Withstand and PD Testing
• Power Cable Withstand Testing

Sansion Power provides high-voltage testing equipment and professional field testing services for substations, GIS, transformers, cables and other high-voltage electrical equipment.

Contact Sansion Power to discuss your GIS testing requirements and project conditions.