I. Product overview
The device is mainly for AC voltage test of XLPE cable, hydraulic generator, power transformer, busbar and GIS. It has wide application scope. It is an ideal withstand voltage device for high voltage test department and power installation and repair engineering unit.
The device is mainly composed of frequency power source, excitation transformer, reactor, capacitor voltage divider, compensation capacitor (optional).

2.vantages of series resonance
* The required power supply capacity is greatly reduced. The series resonant power supply produces high voltage and high current by reactor and the capacitance of the tested product in resonant. In the whole system, the power supply only needs to provide active power consumption of the system, therefore, the power required for the test is only 1/Q of the test capacity.
* The weight and dimension of the equipment are greatly reduced. The series resonant power supply not only eliminates the bulky high-power voltage regulator and the ordinary high-power frequency test transformer, but also requires the 1/Q of the resonant excitation power to reduce the weight and dimension of the system, which is generally 1/10-1/30 of the common test device.
*  Improve the waveform of the output voltage. The resonant power supply is a resonant filter circuit, which can improve the waveform distortion of output voltage and get a good sinusoidal waveform, which effectively prevents the peak breakdown of the harmonic peak to the test product.
* Prevent large short circuit current burn fault point. In the series resonant state, when the insulation weakness of the test product is burn down, the circuit detuns immediately and the circuit current drops rapidly to 1/Q of the normal test current. When parallel resonant or test transformer is used to withstand voltage test, the breakdown current will increase dozens of times. Compared with the two way, the short-circuit current and breakdown current are hundreds of times different. Therefore, the series resonance can effectively find the weakness of the insulation, and there is no hidden trouble in the fault point of the large short circuit current burn.
* There will be no recovery over-voltage. The sample breakdown, due to the loss of the resonant conditions, high voltage arc disappeared immediately, high voltage arc also immediately extinguished, and the recovery voltage of the re establishment is a long process, it is easy to disconnecting the power before reach the flash-over voltage again, the voltage recovery process is a kind of energy accumulation batch process, the process is long, and there will be no recovery over voltage.

3. The main functions and technical features of the frequency series resonant test device are as follows
? The device has over-voltage, over-current, zero start, system detuning and flash-over protection function. The over-voltage and over-current protection value can be set according to user's needs, and the flash-over protection action to protect the product.
? Small volume, light weight, very suitable for the operation of the people on the spot.
? The device has three working modes, which is convenient for users to choose flexibly according to the field conditions and improve the test speed.
The working modes are: full automatic, manual and automatic tuning manual boost mode.
? The data can be stored and printed in different places. The data number is numbered is convenient to help the user to identify and find the data.
? When the device automatically sweeps the frequency, the starting point of frequency can be set arbitrarily in the specified range. Meanwhile, the LCD screen displays the scanning curve, which is convenient for users to directly understand whether the resonance point is found .
? Using the DSP technology, it can easily increase and decrease the function and upgrade according to the needs of the user, and also make the human-computer exchange interface more humanized.