The role of the cable connector in the power system is very important. The quality of cable joints not only affects the safety and reliability of cable line operation, but also affects the reliability of the entire power system operation. Therefore, it is very important to make cable joints and improve the quality of cable joints for improving the reliability, economy and safety of the power system.

With the continuous development of China's economic construction and the continuous improvement of the automation level of power system, higher requirements are also put forward for the quality level of cable joints. There are many cable lines used to connect and install electrical equipment in the power system, especially those used for laying various underground pipelines and for various equipment in buildings. Many of these cable lines are buried underground or laid below the ground, due to the soil resistivity, temperature, humidity and other environmental factors are greatly affected, so it is difficult to ensure that there is no fault under normal operating conditions, so that it is difficult for operation and maintenance personnel to find and deal with the fault in time. On the other hand, because these underground pipelines and power cable lines used by various equipment in the building are directly laid underground or on the ground using metal armor or metal sleeves and other shields. When these electrical equipment need to stop running due to power failure, maintenance and other reasons, because the power in these cable lines can not be quickly exported to make the fault point can not be dealt with in time. In order for these electrical equipment to operate under normal conditions, frequent insulation testing and maintenance are required. The tools used in the test and maintenance are various insulated joints, junction boxes, pressure test stands, etc. The instruments and equipment used in insulation testing and maintenance mainly include voltage test bench, insulation resistance tester and so on. These instruments are usually only used in testing and maintenance, and are operated manually. Because these instruments and equipment are more difficult to operate, they can only be used for testing insulation resistance and leakage current on cables. These instruments and equipment need to carry out tests on the cable with different voltage levels and different capacities to check and test whether various electrical equipment and lines in the cable line can withstand short circuit, grounding, overload and other faults under normal voltage under normal operating conditions.