In the power system, as one of the core equipment, the insulation performance of the generator is directly related to the safe and stable operation of the power grid. With the widespread operation of high-voltage and large capacity generator sets, how to scientifically and accurately select AC resonance testing systems has become a focus of attention in the power industry.

Selection core: Based on generator capacity and voltage level

The selection of voltage withstand test for generators is primarily based on the capacity and voltage level of the generator. Generators with different capacities and voltage levels have vastly different requirements for the output voltage, capacity, and frequency range of the testing device.

For larger capacity generators, higher specification devices need to be selected. When selecting, the reactor configuration and capacity matching device should be selected based on the actual parameters of the generator.

Key parameters: phase capacitance and test frequency

The selection and configuration of generators mainly depend on three elements: test voltage U, equivalent capacitance Cx, and the required test frequency range. Among them, the relative electrical capacity of the generator is one of the key parameters determining the selection of the device, which can usually be obtained by querying the model and manufacturer of the generator. The phase capacitance of a typical generator is between 0.1-0.5 μ F.

In terms of test frequency, the AC withstand voltage test of the generator requires the use of power frequency voltage. According to national standards, the frequency of power frequency voltage is defined as 45Hz-65Hz, but in many testing scenarios, it is required to conduct AC tests on the generator at 50Hz ± 2Hz. Therefore, for the testing device of the generator, the frequency should be as close as possible to the power frequency (45-65Hz). The output frequency range of the frequency conversion resonance test device for Wuhan UHV is 30-300Hz, which can meet the test frequency requirements of different power equipment. Its resonance voltage waveform is a sine wave with a waveform distortion rate of less than 1.0%, ensuring the accuracy and reliability of the test results.

Technical advantages: efficient, safe, and portable

The series resonance withstand voltage test utilizes the LC series resonance principle to test the insulation performance of high-capacity capacitive equipment such as generator stator windings. When the inductance of the reactor in the test circuit reaches resonance with the capacitance of the test object at a specific frequency, the circuit exhibits pure resistance characteristics, and only a very small excitation power is required to generate high test voltage at both ends of the test object.

Compared to traditional testing equipment, frequency conversion series resonance technology has significant advantages: the required power supply is only 1/Q of the test capacity, greatly reducing the requirements for the test power supply; The weight and volume of the equipment have been significantly reduced, generally ranging 1/10 to 1/30 of that of ordinary testing devices; The resonant filtering circuit can improve the distortion of the output voltage waveform, obtain a good sine waveform, and effectively prevent the false breakdown of the test sample by harmonic peaks; When the test sample breaks down, the circuit immediately becomes detuned, and the circuit current rapidly decreases, without causing large short-circuit currents to burn the fault point.

Intelligent protection and convenient operation

The modern series resonance test device is equipped with a comprehensive protection system. The Wuhan UHV device has protection functions such as overvoltage, overcurrent, zero start, and system detuning (flashover). When the test sample experiences insulation breakdown or flashover, the device can quickly detune within 10ms, and the circuit current instantly drops to 1/Q of the normal test current, effectively preventing high current burning the test sample. The device is easy to operate, with a blue screen display of test data and status, and real-time operation step prompts.

Customized services to meet special needs

Wuhan UHV also provides customized services for testing needs of different voltage levels and special scenarios. The device adopts a modular design, which can flexibly combine boost reactors and excitation transformers, covering voltage withstand test scenarios 10kV to 500kV. Whether it is a large hydroelectric generator, main transformer, or GIS equipment, this device can be used for efficient and safe testing.

Wuhan UHV Power Technology Co., Ltd. is a high-tech enterprise specializing in the field of high-voltage power testing. The company's products cover more than 100 types in 15 categories, including series resonance testing devices, partial discharge testing systems, and high-voltage insulation and withstand voltage equipment. If you need customized solutions for variable frequency series resonance testing devices, you can visit the official website or consult a professional team for technical support.