By hvhipot 
HV Hipot Electric Co., Ltd. specializes in producing series resonance (also known as AC withstand voltage test equipment). Next, we will share with you an application example of frequency modulation series resonance.
Calculation within the broadband range of 30-300Hz. (Taking the following parameter devices as an example, only used to master the calculation method, the specific parameters of the user device can be found on the device nameplate):
Reactor specifications and parameters:
26kV 1A32-300Hz 60min
Excitation transformer parameters:
6kVA 1.56kV*432-300Hz
Experimental task:
600 meter 185mm226/35kV cross-linked cable AC withstand voltage test
(1) Determine the cable parameters for a 600 meter 185mm 226/35kV cross-linked cable.
(2) Determine the test voltage. According to the regulations, the test voltage is 2U0, which means 2 * 26kV=52kV for 60 minutes.
(3) According to the rated voltage of the reactor, which should be greater than or equal to the test voltage, select two reactors in series (i.e. meeting the requirement of 26kV * 2252kV).
(4) According to the table, the cable capacitance is 0.163 * 0.6=0.0978uF.
(5) Initial calculated test current: l=UWC=52 * 6.28 * 32 * 0.0978/1000=1.022A (in the formula, the frequency is measured by reactance and the rated frequency is 32Hz)
(6) Select two column reactors in parallel (i.e. 1A * 2 ≥ 1.022A).
(7) Calculate the test frequency based on inductance and capacitance: f=1/(2 π√ LC)=1/(6.28 * √ 129.3 * 2/2 * 0.0978/100000)=44.83Hz
(8) The frequency of 44.83Hz meets the requirements of 30-300Hz. Verification test current: 1=52 * 6.28 * 44.83 * 0.0978/1000=1.43A (where the frequency is substituted into the actual resonant frequency)
(9) Confirm again that the rated current of the reactor is greater than 1.43A (1A * 221.43A).
(10) Select the wiring method for the high-voltage winding of the excitation transformer based on the magnitude of the test current. Due to the high voltage of the excitation transformer, the current per winding is 1.5/1.56=0.96A. 1.43/0.96=1.49 columns. Choose the high voltage winding of the excitation transformer as the two series and two parallel connection method (i.e. medium voltage connection method)
Conclusion: The reactor adopts a fHV Hipot Electric Co., Ltd. section two series two parallel connection, and the excitation transformer high-voltage winding adopts a two series two parallel connection.