The method to find resonance point in cable series resonance test

The cable series resonance test refers to the AC withstand voltage test of the cable using the series resonance test device. In addition, the device can also perform insulation tests on transformers, GIS, and electrical equipment other than large capacity.

GDTF series cable frequency conversion series resonance test device

                                                                                    HV Hipot GDTF series cable frequency conversion series resonance test device

However, when doing this type of test, we often encounter various problems, such as wiring method, finding resonance point, flashover fault, etc. The reconnection resonance test device we use is designed according to The technical parameters are customized and produced, so it is not fully compatible. For this reason, for small electrical equipment, we will introduce the main reasons and solutions for the lack of resonance points in the cup resonance.

If we want to solve the problem that the resonance point cannot be found in the series resonance, first of all, we must understand the idea and method of the series resonance: it can be transformed. The size of the resonant is adjusted, and the resonance is composed of the inductor L and the capacitor C. The resonance phenomenon occurs at one or several frequencies. That is to say, if the series resonance wants to generate a “resonant voltage”, the frequency is adjusted to make the capacitive reactance and the inductive reactance occur.

If you don’t understand the resonance conditions, you can first look at what is joint resonance and what is parallel resonance.
The main reason why the resonance point cannot be found in small-capacity series resonance is that the capacitance is too small and the reactance is too large, which causes the resonance condition to exceed the resonance frequency and the resonance point cannot be found. It can be solved by the following two methods: in the series resonance test device The compensation capacitor is connected in parallel in the loop, and the series and parallel modes of the reactor are adjusted to reduce or increase the inductance.