The AC  voltage tester design and manufacture of the main electrical equipment such as the main transformer, bus switch and the main needle 10kV cable below. The reactor is designed separately, which not only meets the requirement of high voltage and small current equipment test conditions, but also meets the requirement of low voltage AC withstand voltage test such as 10kV cable. It has a wide application range. It is an ideal withstand voltage equipment for high voltage test departments at prefecture, city and county levels, as well as for power installation and repair engineering units.

The device is mainly composed of variable frequency power supply, excitation transformer, reactor and capacitor voltage divider.

(1) HYG means the factory type

(2) Technical specifications of HYG-88kVA/44kV frequency conversion series resonance test device

1. Rated voltage: 

22kV - - meet the AC withstand voltage test of 10 kV cable; 

44kV - - AC  voltage tester for 10 kV substation system;

2. Output voltage waveform distortion rate: <1.0%

The advantages of series resonance tester in power system application:

1. The required power supply capacity is greatly reduced. Series resonant power supply generates high voltage and large current by resonant reactor and capacitor resonance. In the whole system, the power supply only needs to provide the active power consumption part of 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 greatly reduced. In series resonant power supply, not only the heavy high-power voltage regulator and common high-power power test transformer are omitted, but also the resonant excitation power supply only needs 1/Q of the test capacity, which greatly reduces the weight and volume of the system, generally 1/10-1/30 of the ordinary test equipment.

3. Improving the waveform of output voltage. Resonant power supply is a resonant filter circuit, which can improve the waveform distortion of the output voltage, obtain good sinusoidal waveform, and effectively prevent the wrong breakdown of the sample by harmonic peak.

4. Prevent large short circuit current from burning fault points. In the series resonance state, when the insulation weakness of the sample is broken down, the circuit immediately detuning and the loop current rapidly drops to 1/Q of the normal test current. When the shunt resonance or test transformer is used for withstand voltage test, the breakdown current increases tens of times immediately. Compared with the two methods, the short circuit current is hundreds of times different from the breakdown current. Therefore, series resonance can effectively find the insulation weakness, and there is no big short-circuit current burn fault point.

5. There will be no recovery overvoltage. When the sample breaks down, because of the loss of resonance condition, the high voltage also disappears immediately, the arc extinguishes immediately, and the process of rebuilding the recovery voltage is very long. It is easy to disconnect the power supply before reaching the flashover voltage again. This process of voltage recovery is an intermittent oscillation process of energy accumulation, and it has a long process without any recovery overvoltage.

The main functions and technical characteristics of our FM resonant device are as follows:

1. The device has protective functions such as over-voltage, over-current, zero-position start, system detuning (flashover). The over-voltage and over-current protection value can be set according to user's needs. The flashover protection action when the test product flashes off and the flashover voltage value can be recorded for test analysis.

2. The weight of the whole unit is very light, the maximum is not more than 40 kg, which is convenient for field use.

3. The device has three working modes, which make it convenient for users to choose flexibly according to the site conditions and improve the test speed.

The working modes are: full automatic mode, manual mode and automatic tuning manual boost mode.

4. The data number that can be stored and stored is digital, which is convenient for users to identify and search.

5. The starting point of frequency can be set arbitrarily in the prescribed range when the device scans frequency automatically. The direction of frequency scanning can be selected up and down. At the same time, the scanning curve can be displayed on the large LCD screen, so that users can intuitively know whether to find the resonance point.

6. Adopting the technology of DSP platform, it can add or subtract functions and upgrade conveniently according to users'needs, and make the man-machine interface more humanized.