The SXBP portable variable frequency series resonance withstand voltage complete set is specially developed for AC withstand voltage tests of power equipment rated at 110kV and below.

Its reactors and excitation transformers are manufactured with dry-type epoxy casting technology. Featuring compact structure and light weight, the equipment is easy to transport to substation sites, cable trenches and construction fields. The reactors support flexible series and parallel combination. One single set is capable of conducting withstand voltage tests on power transformers, GIS, circuit breakers, transformers, high-voltage bushings, high-voltage cross-linked cables, medium & small generators and motors within the 110kV voltage class. It is the mainstream withstand voltage testing equipment for power maintenance, handover tests of power projects and factory inspection of electrical equipment.

• Cables: AC withstand voltage test for 10kV, 35kV, 110kV high-voltage cross-linked power cables.
• Primary Power Equipment: Insulation withstand voltage detection for 110kV-and-below GIS, circuit breakers, CT/PT and main transformers.
• Rotating Equipment: Insulation AC withstand voltage test for medium & small generating units and high-voltage motors.

The whole series resonance system consists of four core assemblies: variable frequency excitation power supply cabinet, excitation step-up transformer, dry air-core reactors and capacitive voltage divider.

1. Lightweight & Portable Design

   Each individual component weighs less than 50kg, easy to be carried by one or two workers. It perfectly fits field tests in wild areas, underground cable tunnels and narrow spaces inside substations to save time for transportation and layout.

2. Modular Building-block Reactors

   Adopting stacked modular structure, reactors can be freely connected in series or parallel according to test voltage and test sample capacity. Strong universality to match tests for cables of different lengths and equipment of various voltage levels.

3. Wide & Stable Frequency Output

   Adjustable working frequency ranges from 30Hz to 300Hz. Different from power frequency test power supply, resonance principle greatly reduces the required input power capacity. Ordinary commercial mains electricity can support high-power withstand voltage tests on site.

4. High-quality Output Waveform

   Standard sine wave for high-voltage output with waveform distortion rate ≤1%. Accurate test data meets national standard requirements and avoids overvoltage damage to tested electrical equipment.

5. Simple Wiring & Easy Operation

   Standardized circuit layout with marked wiring terminals. Field technicians can finish wiring quickly with reference to drawings for user-friendly operation procedures.

6. Intelligent Control & Comprehensive Safety Protection

   Equipped with intelligent variable frequency control system for automatic whole testing process. Multiple protection functions including overvoltage, overcurrent, flashover breakdown, overheating and detuning ensure high operation stability and safe testing process.

7. Test Data Storage & Traceability

   Built-in data query and storage module supports access to historical test records, voltage curves and breakdown data for report filing and project document management.

A Variable Frequency Series Resonance Test System is a high-voltage AC withstand voltage testing device that uses resonance technology to generate high test voltage with lower input power capacity.

By adjusting the output frequency to achieve resonance between the inductive reactor and capacitive load of the tested equipment, the system can efficiently produce stable high-voltage AC output for insulation performance testing.

It is widely used for AC withstand voltage tests of high-voltage cables, GIS, transformers, switchgear and other electrical equipment.

The portable variable frequency series resonance test system is mainly designed for insulation withstand tests of:

• 10kV, 35kV, 110kV power cables
• Gas Insulated Switchgear (GIS)
• Circuit breakers
• Current transformers (CT) and voltage transformers (PT/VT)
• Power transformers
• High-voltage busbars
• Motors and generators
• Other high-voltage electrical equipment

It is suitable for factory testing, commissioning tests, preventive maintenance tests and acceptance tests.

The complete test system mainly consists of:

• Variable frequency power supply
• Excitation transformer
• Fixed reactors
• Capacitive voltage divider
• Control and measurement unit
• Connecting cables and accessories

The modular structure allows flexible combination according to different voltage levels and test capacity requirements.

Compared with traditional AC withstand voltage test equipment, this system offers:

• Lower power supply requirement: Resonance technology reduces the required input capacity during high-voltage testing.
• Portable modular design: Individual components are lightweight and convenient for transportation and field installation.
• Stable output waveform: Output voltage waveform distortion is ≤1%, meeting relevant testing requirements.
• Flexible configuration: Reactor modules can be combined according to different test objects.
• High interference resistance: Suitable for complex electromagnetic environments in substations.
• Simple operation: Intelligent control system improves testing efficiency.

The test frequency range is:30Hz～300Hz

The wide frequency adjustment range allows the system to perform AC withstand voltage tests on different types of capacitive loads.