When it comes to the series resonance test device, professionals are very familiar with it. The series resonance test device is mainly used for AC withstand voltage testing of electrical main equipment such as 10kV and 35kV cables, 35kV main transformers, busbars, switches, insulators, etc. It can meet the requirements of high voltage and low current equipment testing conditions, as well as the requirements of low voltage AC withstand voltage tests such as 10 kV cables. Next, we will learn the testing method of the series resonance test device.
(1) The current selection is based on the current IC required by the electrical equipment, and the rated output current IN of the series resonance testing device is selected so that the current IC required by the series resonance testing device is greater than the required current IC, i.e. IN>IC, and the required current IC can be estimated according to the following formula. The rated output current of the test transformer is IN=770 A
(2) Select the voltage according to the test voltage requirements, choose a series resonance test device with appropriate voltage, and ensure that the rated voltage on the high-voltage side of the test transformer is greater than the test voltage Uc, that is, Un>Uc; Next, check that the side voltage required for the low-voltage side test transformer matches the on-site power supply voltage and voltage regulator.
(3) Selection of Capacity for Series Resonance Test Device
The capacity of the series resonance test device should be as large as possible than the calculated result, because there is stray capacitance between the test line and the test equipment, which makes the estimated test current smaller than the actual value. Due to the large capacitance of cable lines, large capacity test transformers, voltage regulators, power supplies, and other series resonance test equipment are required to conduct a 50 Hz voltage test.
(4) Detection of Insulation Defects by Series Resonance Test Device
Insulation defect detection is a strict, effective, and direct detection method that has decisive significance in determining whether electrical equipment can continue to operate. It is also an important means to ensure the insulation level of equipment and avoid insulation accidents. Insulation defect detection tests the insulation level of equipment near operating conditions. This is a destructive test on the equipment. It may cause new damage to the insulation layer or exacerbate the original damage to the insulation layer, but these damages do not rupture during pressurization. The insulation damage caused by the series resonance test device is irreparable. If the series resonance test device continues to be put into use, it will cause great harm.