With the development of the national economy and the improvement of the power supply voltage level of the city network, XLPE insulated power cable (XLPE) has gained more and more domestic and foreign with its reasonable technology and structure, excellent electrical performance and safe and reliable operating characteristics The more widely used. Great progress has been made especially in the field of high-voltage power transmission. Compared with oil-filled cables, cross-linked cables are easy to lay and install, simple to operate and maintain, and there is no oil flowing problem. However, recent years of operation and research have shown that the insulation of cross-linked polyethylene cables is prone to branching discharge during operation, causing insulation aging damage and severely affecting the service life of cross-linked polyethylene insulated power cables. Therefore, fully understanding the insulation characteristics of cross-linked cables and timely and effective detection and prevention of certain defects in insulation are of great significance for ensuring the safe operation of equipment and systems. The main factors affecting the insulation of the cross-linked cable and the principles of the cable transfer test are described. It is considered that it is necessary and feasible to carry out the AC withstand voltage test on the cross-linked cable on the site.

    In order to ensure the safe and reliable operation of the cable, the relevant international standards have clearly defined various tests for the cable. The main test items include: measuring insulation resistance, DC withstand voltage and leakage current. Among them, the measurement of insulation resistance is mainly to check whether the cable insulation is aging, moisture, and insulation defects exposed in the withstand voltage test. The DC withstand voltage and leakage current tests are performed simultaneously, the purpose of which is to find defects in the insulation. However, in recent years, domestic and international tests and operating experience prove that the DC withstand voltage test cannot effectively find the insulation defects in the cross-linked cable, and even cause hidden dangers in the insulation of the cable. German Sechiswag company had 87 faults in 10 kV voltage XLPE cables with 41 circuits from 1978 to 1980; Sweden's 3 kV to 24.5 kV voltage XLPE cables were put into operation over 9,000 km and 107 faults occurred There have been many cable accidents in China, and a considerable number of cable failures are caused by the negative effects of frequent DC withstand voltage tests. Therefore, relevant domestic and foreign authorities have widely recommended the use of AC withstand voltage instead of the traditional DC withstand voltage.

    The XB-F series variable frequency series resonance test device developed and produced by Wuhan Xinchunda Power Equipment Co., Ltd. uses the principle of series resonance, uses an excitation transformer to excite the series resonance circuit, adjusts the output frequency of the frequency conversion controller, and connects the loop inductance L and the test product C in series. Resonance, the resonance voltage is the voltage applied to the test sample. This product is suitable for 10KV, 35KV, 110KV, 220KV, 500KV polyhexene power cable AC withstand voltage test; suitable for 60KV, 220KV, 500KVGIS AC withstand voltage test; suitable for large-scale transformers, generator sets power frequency withstand voltage test; power transformers Induction withstand voltage test; ground resistance measurement and other high voltage withstand voltage tests, which are widely used. Automatically and manually tune, quickly find resonance points, high stability and reliability, and friendly human-machine interface. It is a very convenient test device for AC voltage withstand tests in power system, metallurgy, petroleum, chemical and other industries. The majority of users agree and praise.