Variable Frequency AC Resonance Test System

KVXZ-270kVA/270kV Variable Frequency AC Resonance Test System is applied for AC dielectric test for electric equipment

Product Description


KVXZ-270kVA/270kV Variable Frequency AC Resonance Test System is applied for AC dielectric test for electric equipment.

  1. 10kV/300mm2cable 3km AC withstand test,capacitance≤1.1265uF,test frequency:30-300Hz, test voltage 22kV, test time 5min;
  2. 35kV/300mm2cable 1km AC withstand test,capacitance≤0.1945uF,test frequency:30-300Hz, test voltage 52kV, test time 60min;
  3. 110kV/630mm2cable 0.2km AC withstand test,capacitance≤0.0368uF,test frequency:30-300Hz, test voltage 128kV, test time 60min;
  4. 110kV/63000kVA Transformer AC withstand test,capacitance≤0.02uF,test frequency:30-300Hz,test voltage below 160kV, test time 1min;
  5. GIS 110kV, Switching busbar and other substation equipment, AC withstand test,test frequency:30-300Hz, test voltage below 265kV,test time 5min


  • With the function of over-voltage, over-current, zero-start, system detune (flashover) protection. Over-voltage, over-current protection value can be set accordingly to user’ need. Flashover protection action whenthe test object flash over and tester records the flashover voltage value for testing analyze.
  • Small volume, light weight, very suitable for the operationpeople on the spot.
  • There are three kinds of working modes, which is convenient for user choosing according to on-site condition.Working modes : Automatic mode,  Manual mode,  Automatic tuning manual boost mode.
  • Data can be storedand printed in different places, and the series numbers are figures which is convenient for identification and searching.
  • 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 .
  • AdoptingDSP technology, which can increase and decrease functions and updated accordingly to the user’s need, it also makes the human-machine interface more humanized.
  • Reduced greatly the required power capacitance , resonant equipment power can generate high voltage and large current by using the resonance of resonant reactor and test capacitor. Power can supply the loss power in the system , which only requires 1/Q of the resonant excitation power during the test .
  • Reduced greatlyweight and dimension of the equipment . The series resonant power supply not only eliminates the bulky high-power voltage regulator and 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 output of voltage wave .The resonant power supply is a resonant filter circuit, which can improve the waveform distortion of output voltage and get the good sinusoidal waveform effectively preventing the error breakdown of the harmonic peak to the test object.
  • Prevent large short circuit current burn fault point. When test object is breakdown in the series resonant state,the circuit is detuned immediately and the circuit current drops rapidly to the 1/Q of normal tested current .The breakdown current increase to dozens of time during power frequency withstand test of transformer. Compared with two test methods , short current and breakdown current is hundreds of times different . Resonance test equipment can efficiently find the insulation weakness and large short circuit current burn fault point.
  • No-recovery over-voltage . When test object is break down , high voltage immediately disappear also immediately extinguished due to the loss reasonance condition. It takes a long time to recovery flashover voltage before cutting off the power .This voltage recovery process is a kind of energy accumulation of intermittent oscillation process, there is no any recovery over-voltage in the process .


Test equipment combination mode

Combinations of equipment


Tested specification

Reactors(44kVA/22kV, 4 sets ) Excitation transformer output selection Test voltage (kV)
Cable 10kV/300mm²: length 3km 3 reactors in parallel

(Three of them are grounded)

4kV ≤22kV
Cable 35kV/300mm²: length 1km 2 in series and 3 groups in parallel 4kV ≤52kV
Cable 110kV/630mm²: length 0.2km 3 in series and 2 groups in parallel 4kV ≤128kV
Power transformer 110kV/63000kVA 4 reactors in series 8kV ≤160kV
110kV GIS, switchgear, etc. 6 reactors in series 16kV ≤265kV

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