The shock test of the power system is divided into three types:

1. The pulse test method is specified, and the sine wave is used for the test. Such as sine wave vibration testing machine, widely used in national defense, aerospace, aviation, communications and other industries, to adapt to the detection of early faults, simulation of actual working conditions and structural strength tests.
2. Impact spectrum test method. For example, the impact test bench can control the size and duration of the impact force to accurately test the adaptability of the product to the environment. It is also often used to test whether the packaging of the product can protect the product and avoid The product was damaged during shipping and handling.
3. Specify the test method of the testing machine. For example, the crushed stone impact tester is specially designed for the anti-gravel impact test of automobile materials and surface coatings.

According to the temperature, the impact test is divided into: normal temperature impact test, test at normal temperature, generally in the range of 23 ± 5 degrees Celsius; low temperature impact test; stored in a low temperature medium for a certain period of time, so that the temperature reaches the required speed. Take out to complete the impact test.

In the power grid system, the newly put into operation of the transformer, in addition to doing some necessary tests, protection and secondary tests according to the handover test standards, before the formal commissioning, usually do no-load full-voltage closing impulse test, and for There are two purposes for the impulse closing test of the transformer.

First, in the case of no electricity, when the no-load transformer is opened, it may generate operating overvoltage. When the neutral point of the power system is not grounded or is grounded through the arc suppression coil, the amplitude of the overvoltage can reach 4~4.5 times the phase voltage. ; When the neutral point is directly grounded, it can reach 3 times the phase voltage. Therefore, in order to check whether the insulation strength of the transformer can withstand full voltage or operating overvoltage, an impact test is required.

The second is that in the case of live, when the no-load transformer is put into operation, an excitation inrush current will be generated, and its value can reach 6~8 times the rated current. Because the excitation inrush current generates a large electromotive force, in order to assess the mechanical strength of the transformer, at the same time assess the excitation Whether it can cause malfunction of the relay protection device in the early stage of inrush current attenuation requires an impact test.

Usually, the newly installed transformer is generally required to close five times at no-load to comprehensively detect the insulation, mechanical strength and differential protection of the transformer. Because the closing angle is different at each closing time, the corresponding excitation inrush current is also different, sometimes large, sometimes small. After the first impact, it should continue to run for more than 10 minutes, and the subsequent impact should wait for more than 5 minutes before the next impact, once A full impact test usually takes 1 hour.

Therefore, when the impact test is completed, it means that the substation can be put into formal operation.