This device is primarily designed for AC voltage withstand tests of cross-linked cables, hydro generators, main transformers, busbars, GIS, etc. It has a wide range of applicability and is an ideal voltage withstand equipment for high-voltage testing departments at the local, municipal, and county levels, as well as for power installation and maintenance engineering units.
The device primarily consists of a variable frequency control power supply, excitation transformer, reactor, capacitive voltage divider, and compensation capacitor (optional).
Advantages of series resonance in power system applications:
1. The required power capacity is significantly reduced. The series resonant power supply generates high voltage and large current through the resonance between the resonant reactor and the capacitance of the tested object. In the entire system, the power supply only needs to provide the active power consumption in the system. Therefore, the power required for the test is only 1/Q of the test capacity.
2. The weight and volume of the equipment are significantly reduced. In a series resonant power supply, not only are bulky high-power voltage regulators and conventional high-power mains frequency test transformers eliminated, but also the resonant excitation power supply only requires 1/Q of the test capacity, resulting in a substantial reduction in system weight and volume, typically being 1/10 to 1/30 of that of conventional test equipment.
3. Improve the waveform of the output voltage. The resonant power supply, which is a resonant filtering circuit, can improve the waveform distortion of the output voltage, achieving a good sine waveform and effectively preventing the harmonic peaks from causing accidental breakdown of the test sample.
4. Prevent large short-circuit currents from burning the fault point. In the state of series resonance, when the insulation weakness of the test sample is punctured, the circuit immediately detunes, and the loop current rapidly drops to 1/Q of the normal test current. However, when conducting voltage withstand tests using parallel resonance or a test transformer, the puncture current immediately rises by several tens of times. Compared to the two, the short-circuit current differs from the puncture current by hundreds of times. Therefore, series resonance can effectively identify insulation weaknesses without the hidden danger of large short-circuit currents burning the fault point.
5. No recovery overvoltage will occur. When the test sample breaks down, due to the loss of resonance conditions, the high voltage immediately disappears, and the arc is extinguished instantly. Moreover, the process of re-establishing the recovery voltage is very long, making it easy to disconnect the power supply before reaching the flashover voltage again. This voltage recovery process is an intermittent oscillation process of energy accumulation, which is long and does not exhibit any recovery overvoltage.
Product nickname: Series resonance, variable frequency resonance, variable frequency series resonance, series resonance test equipment, series resonance voltage withstand device, cable voltage withstand series resonance device
