Cable withstand test is a kind of AC voltage test, also called power frequency withstand voltage test.

　　AC voltage withstand test is in the finished cable insulation above the working voltage is applied is higher than the rated voltage of a certain multiple voltage value will not be to keep the insulation breakdown within a certain period of time of the cable. For each insulated cable product that will be used for power transmission, each product must be tested prior to leaving the factory. The purpose of the pressure test is to check the reliability of the operation of the product under operating voltage and to find out the defects in the insulation in a relatively timely manner. But the most important thing is to find out the defects in the production process. For example: insulation, damage to the internal and external parts, the conductor has a serious defect that can cause sharp distortion of the electric field, etc.. (1) cable withstand test voltage of the selected principle is: not only can find serious flaws in insulation, but also does not cause damage to the insulation, insulation of the injury caused directly. The withstand time of general cable products is about 5 minutes. (2) pressure test equipment requirements: test voltage and frequency should be to AC voltage between 60 Hz to 40 Hz, the voltage waveform must be close to the sine wave, the ratio between the peak value and the effective value according to the test voltage values of samples and pressure time product standards for reference. (3) next we come to know the specific operation method of pressure test. The first is the test sample preparation method: 1. test length and head for the terminal part of the terminal must be guaranteed under the provisions of the cable withstand test voltage will not occur on the surface of the discharge or internal breakdown. If need to be tested in the tank experiment and the two ends out of the water length cannot be less than 200mm, and must ensure that under the provisions of the test voltage, does not occur along the surface of the discharge. 2. the steps of the pressure test: the test procedure must meet the requirements of the operating procedures of the pressure test. When the pressure test is carried out, the difference between the temperature of the pressure test and the temperature of the surrounding environment shall not exceed 3 degrees centigrade. The voltage shall start at lower values, rise slowly and relatively smoothly to the required test voltage, and maintain the specified resistance time. In the lower voltage, until reduced to cable voltage withstand test voltage specified value 40%, can cut off the power supply, it is absolutely not allowed to cut off the power suddenly in high pressure case, this is done in order to avoid overvoltage. 3. voltage test evaluation: test cable within the prescribed time, continue to test it, play cable, without any breakdown occurs, you can think that the experimental product passed the power frequency compression test. However, in the course of the test, the end or end of the cable line has been discharged along its surface or has been subjected to internal breakdown, and another terminal connection may be allowed, and repeated tests shall be carried out. Unless there are special requirements in the product standards, all cable withstand test procedures need to be re timed. During the test process, if because of the blackout stop pressure test, when to test, unless there are special provisions in the product standard, other experiments must be re timing. (4) the need to pay attention: 1. AC voltage withstand test test equipment need to be performed periodically on the verification; should protect the device with fast current 2. pressure test loop. The purpose is to ensure that when the breakdown and some special cases of the pressure test, the power supply can quickly remove test. 3. in the surrounding area should be equipped with pressure test grounding metal fence, the cable voltage test area entrance and export position linkage control, signal lamp and a high voltage danger warning signs and so on a series of security measures. 4. grounding shall be provided in the area of the voltage test, and the resistance must be less than 4 ohms. Grounding transformer and cable grounding test end is connected or additional electrode can and grounding reliable connection. The above is the small series through the pressure test principle, equipment requirements, methods and pressure test notes, these four aspects for the specific introduction of the cable pressure test. I believe we have some understanding of this experiment, and if there are any problems, welcome to our "Shen Xing cable group" technical customer service related advice.