As high-voltage power transmission grids expand, Gas-Insulated Switchgear (GIS) technology has become essential for urban substations due to its compactness, safety, and reliability. Before energizing a new high-voltage GIS substation, standard commissioning protocols require strict AC High Voltage Withstand Testing (AC Hipot Test) to verify internal insulation integrity after transportation and assembly.

Recently, Sanison Power supported an international power contractor in performing a full-scale field AC withstand voltage test on a 275kV GIS system. Utilizing our advanced SXBP Series Variable Frequency Resonant Test System, the project team successfully completed the site commissioning test.

• Large Capacitive Load: 275kV GIS switchgears present high capacitance. Traditional test transformers would require excessive weight, massive physical dimensions, and huge power source capacity, making field transportation impractical.

• Strict Pure Sine Waveform Requirements: High-voltage GIS insulation requires an exceptionally clean output waveform to prevent local harmonic breakdown or false voltage stress during testing.

• Site Mobility & Modular Setup: The testing environment requires equipment that is modular, easy to assemble, and capable of fast frequency tuning under restricted substation footprints.

To resolve these challenges, Sanison Power supplied a customized SXBP Series Variable Frequency Resonant Test System.

By applying series resonance technology (L−C resonance), the required power input from the generator or grid is reduced to just 1/Q (where Q≥50 is the system Quality Factor) of the output capacitive power.

• Multi-Reactor Flexible Combination: Modular high-voltage reactors (e.g., 960kVA/130kV per unit) can be connected in series or parallel to handle diverse capacitive loads, including GIS, power transformers, and long-distance XLPE cables (110kV/220kV/500kV).

• Pure Sinusoidal Output: System resonance acts as a natural harmonic filter, guaranteeing output voltage waveform distortion $le 1%$, protecting high-value GIS components.

• Advanced Auto-Tuning & Protection: Automatic frequency sweeping (20Hz–300Hz) pinpoints the exact resonance frequency quickly. Multi-tier protections (over-voltage, over-current, flashover, and zero-start) safeguard operators and test assets.

Sanison Power delivers high-performance high-voltage testing solutions engineered for modern grid infrastructure:

• Versatility: A single resonant system caters to GIS, Power Transformers, XLPE Cables, and Capacitive Voltage Transformers (CVT).

• Modular Design: Compact reactor towers enable easy transport and quick setup without heavy machinery.

• Full Technical Support: Comprehensive customized design, quick delivery times, and global technical assistance.