Variable Frequency Series Resonant Test SystemZCVF-A 1500kVA-750kV

Advantages of applying series resonant test system in power systems:
1. The required power capacity is greatly reduced. The series resonant power supply generates high voltage and large current through resonance between the resonant reactor and the tested capacitor. In the entire system, the power supply only needs to provide the active power consumption part of the system. Therefore, the required power supply for the test is only 1/Q of the test capacity.

2. The weight and volume of the equipment are greatly reduced. In the series resonant power supply, not only does it eliminate the bulky high-power voltage regulating device and ordinary high-power power frequency test transformer, but also the resonant excitation power supply only needs 1/Q of the test capacity, greatly reducing the system weight and volume, which is generally 1/10 of the ordinary test device.

3. Improve the waveform of the output voltage. Resonant power supply is a resonant filtering circuit that can improve the waveform distortion of the output voltage, obtain a good sinusoidal waveform, and effectively prevent the accidental breakdown of the test object caused by harmonic peaks.

4. Prevent large short-circuit currents from burning fault points. In the series resonance state, when the insulation weakness of the test object is broken down, the circuit immediately becomes de tuned, and the circuit current rapidly drops to 1/Q of the normal test current. When conducting voltage withstand tests using parallel resonance or test transformers, the breakdown current immediately increases by tens of times, and compared to the two, the short-circuit current and breakdown current differ by hundreds of times. So, series resonance can effectively identify insulation weaknesses without the worry of large short-circuit currents burning fault points.

5. There will be no recovery overvoltage. When the test object experiences breakdown, due to the loss of resonance conditions, the high voltage immediately disappears, the arc immediately extinguishes, and the process of establishing the recovery voltage is 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 cause any recovery overvoltage.

The main functions and technical characteristics of our company’s frequency modulation resonance device:

1. The unit possesses the overvoltage, overcurrent, zero start, system detuning (flashover) and other protective functions. The protective value of over voltage and over current can be adjusted as per requirements of customers. The protective function of flashover also can remember voltage value of flashover when there is a flashover of test object, which can be used for test analysis.

2. The weight of single piece of whole unit is very light with no more than 40kg, which can be convenient for field service.

3. There are three working modes for this unit, which is convenient for users to flexibly select according to field condition and improve the test speed.Three working modes are fully automatic mode, manual mode and the mode with automatic tuning and manual boosting.

4. It can save data with data number of figure, which is convenient for users to identify and search.

5. The frequency sweeping can be set casually within specified scope and the frequency sweeping direction can be selected upward or downward during the automatic frequency sweeping process of the unit. Meanwhile, the large LCD screen can show scanning curve, which is convenient for users to intuitively understand whether they can find the resonance point or not.

6. It adopts DSP platform technology, which is convenient to add or delete functions and upgrade according to customers’ requirements, and enables the man-machine interface to become more humanized.