Product Description
The variable frequency series resonant test device is mainly designed for AC withstand voltage tests of cross-linked cables, hydro generators, main transformers, busbars, GIS, etc. It has a wide range of applications and is an ideal withstand voltage testing device for high voltage testing departments at the regional, city, and county levels, as well as for power installation, repair, and testing units.
The variable frequency series resonant test device is primarily composed of a variable frequency control power supply, excitation transformer, reactor, capacitive divider, and optional compensation capacitor.

Suitable for the commissioning and preventive testing of large capacity, high voltage capacitive test samples. The device features over-voltage, over-current, zero start, and system detuning (flash-over) protection functions. The entire device is lightweight, making it convenient for on-site use.

Product Features
- 1. Significantly Reduced Power Supply Capacity. Series resonant power sources use resonant reactors and the test sample's capacitance to generate high voltage and high current. In the entire system, the power supply only needs to provide the active power consumption, so the required power supply capacity is only 1/Q of the test capacity.
- 2. Greatly Reduced Weight and Volume. The series resonant power source eliminates the need for bulky high-power voltage regulators and ordinary high-power power frequency test transformers. The resonant excitation power supply only needs 1/Q of the test capacity, significantly reducing the system's weight and volume, typically to 1/10 to 1/30 of conventional test devices. Improved Output Voltage Waveform. The resonant power source acts as a resonant filter circuit, improving the output voltage waveform distortion, achieving a good sine wave, and effectively preventing harmonic peak values from causing false breakdowns of the test sample.
- 3. Prevention of Large Short-Circuit Currents. In a series resonant state, if the test sample's insulation weak point is broken down, the circuit immediately detunes, and the loop current quickly drops to 1/Q of the normal test current. In contrast, with parallel resonance or test transformer methods, the breakdown current immediately increases dozens of times, resulting in short-circuit and breakdown currents differing by hundreds of times. Therefore, series resonance effectively identifies insulation weak points without the risk of large short-circuit currents damaging the fault point.
- 4. No Recovery Over-voltage. When the test sample breaks down, the high voltage immediately disappears due to the loss of resonance, the arc extinguishes instantly, and the reestablishment process of the recovery voltage is very long, making it easy to disconnect the power before reaching flash-over voltage again. This recovery process is a kind of energy accumulation intermittent oscillation process, which is long and does not generate any recovery over-voltage.
Product Parameters
- 1. Rated output voltage: based on different test objects, max up to 1000kV.
- 2. Output frequency: 20- 300Hz.
- 3. Waveform: pure sine wave, THD <1.0%.
- 4. Max. capacity: Max up to 20000kVA
- 5. Duty Cycle: Continuous working time 60 mins at full power output.
- 6. Frequency adjustment sensitivity: 0.1Hz, instability <0.05%.
- 7. Power Supply: 380/220V ± 15%/50Hz ± 5%.
- 8. can customzied partial discharge resonant test system
FAQ
- 1.Is your company a sales company or a manufacturer? Sansion Power Electric Co., Ltd. is an industrial and trade enterprise with its own factory, self-produced and self-sold. Founded in 2005, we have twenty years of production experience with reliable production lines, test rooms, and R&D centers.
- 2.Are goods in stock, can they be customized, and what is the delivery time? Goods are made to order according to customer requirements using the latest technology. Delivery time is typically within 10 working days.
- 3.Is the quality guaranteed? We use imported components and conduct three quality inspections before shipment. Export products are packed in non-fumigation wooden boxes.
- 4.What are the after-sales terms? We offer free consulting service, one year warranty, and support through email communication, video calls, and on-site technical assistance to resolve after-sales problems promptly.
- 5.What are the cooperative countries or regions? Products exported to United States, France, Brazil, Australia, Spain, Portugal, Oman, Russia, Netherlands, Indonesia, Bangladesh, Saudi Arabia, Chile, Colombia, Panama, Malaysia and other countries.
About Sansion
Established in 2005, Sansion Power Electric comprises technical experts with over 20 years of experience in R&D, manufacturing, and marketing of power electrical testing products. Our solutions are widely applied across power electric, railroad, energy conservation and environment protection, water conservancy, petrochemical industry, aerospace, and other sectors.
Sansion Power Electric includes R&D department, instruments manufacturing workshop, HV workshop, sample exhibition room, HV testing laboratory, quality control department, general office, sales departments, and information office. We currently employ over 80 staff members, including 20 technical engineers.
We have obtained ISO9001 quality system certification, and all products strictly conform to international IEC and Chinese state standards.



