By hvhipot 
Q: What are the AC withstand voltage testing methods using the series parallel resonance principle?
Answer: For AC withstand voltage testing of large capacity test objects such as long cable lines, capacitors, large generators, transformers, etc., large capacity testing equipment and power series resonances are required, which are often difficult to achieve on site. In this case, series parallel resonance or series parallel resonance (also known as series parallel compensation) can be used according to the specific situation to solve the problem of insufficient capacity of the testing equipment.
(1) Series resonance (voltage resonance) method. When the rated voltage of the test transformer cannot meet the required test voltage, but the current can meet the test current of the tested object, the problem of insufficient test voltage can be solved by series resonance.
(2) Parallel resonance (current resonance) method. When the rated voltage of the test transformer can meet the requirements of the test voltage, but the current cannot reach the test current required by the tested object, parallel resonance compensation current can be used to solve the problem of insufficient capacity of the test power supply.
(3) Series parallel resonance method. In addition to the series parallel resonance mentioned above, when the rated voltage and rated current of the test transformer cannot meet the test requirements, a series parallel resonance circuit, also known as series parallel compensation method, can be used simultaneously.
Q: What are the conditions for voltage resonance? What are the conditions for current resonance?
Answer: In a circuit composed of an inductor coil (which can be simulated by connecting inductor L in series with resistor R) and a capacitor element (capacitor C) in series, voltage resonance occurs when the inductance and capacitance are equal. In depth analysis is as follows:
(1) When l and C are constants, the frequency f of the power supply is exactly equal to the natural oscillation frequency of the circuit, that is, f=1/(2 π√ LC).
(2) When the power frequency is constant, adjust the inductance L so that l=1/[(2 π f) 2C].
(3) When the power frequency is constant, adjust the capacitor C to make C=1/[(2 π f) 2L]. In a circuit composed of an inductor coil (which can be simulated by inductor L in series with resistor R) and a capacitor element (capacitor C) connected in parallel, current resonance will occur if one of the following conditions is met.
1.Power frequency f=1/2 π√ 1/lc-r/L
2. Adjust the capacitor to make C=L/[R2+(2 π FL) 2]
3.When 2 π FCR ≤ 1, adjusting inductance L may also cause current resonance.
HV Hipot Electric Co., Ltd. specializes in producing series resonance (also known as series resonance test equipment) and has been engaged in the electrical measurement industry for many years. Its products have first-class quality and welcome customers to come and purchase.