Shock testing is not a technical term for power systems. It is generally a test method to determine the safety, reliability and effectiveness of military and civilian equipment when it is subjected to external impact or action. The impact test in electrical engineering generally includes operating impact test, lightning impact test, and steep wave front impact test, which aims to test the insulation strength of electrical equipment.
Shock tests for power systems are divided into three types:
1, specify the pulse test method, the use of sine wave test. Such as sine wave vibration testing machine, widely used in defense, aerospace, aviation, communications and other industries, to find early failure, simulate the actual working condition assessment and structural strength test.
2. Shock spectrum test method. Such as the impact test bench, it can be controlled to simulate the size of the impact force, duration, etc., used to accurately test the adaptability of the product to the environment, and is often used to test whether the packaging of the product can protect the product to avoid damage during transportation and loading. 3, specify the testing machine test method. For example, the gravel impact testing machine is specially designed for the anti-gravel impact test of automotive materials and surface coatings.
According to the temperature, the impact test is divided into: normal temperature impact test, the test is carried out at normal temperature, generally in the range of 23±5 degrees Celsius; Low temperature impact test; Store in low temperature medium for a certain time, so that the temperature meets the requirements after the rapid removal to complete the impact test.
In the power grid system, the newly put into operation of the transformer, in addition to some necessary tests and protection, quadratic surface tests according to the handover test standard, before the formal input, usually do no-load full voltage closing impact test, and the transformer impact closing test has two purposes.
First, when the no-load transformer is unplugged, it is possible to generate operating overvoltage. When the neutral point of the power system is not grounded or grounded through the arc suppression coil, the overvoltage amplitude 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 transformer insulation strength can withstand full voltage or operating overvoltage, it is necessary to do a shock test.
Second, in the case of electrization, when the no-load transformer is put into the excitation inrush current, the value can reach 6 to 8 times the rated current, because the excitation inrush current produces a large electrical power, in order to assess the mechanical strength of the transformer, and at the same time, whether the initial decay of the excitation inrush current can cause the relay protection device to misoperate, it is necessary to do an impact test.
In general, the newly installed transformer generally requires no-load closing five times 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 different, sometimes large, sometimes small, after the first impact to continue to run for more than 10 minutes, after the impact to wait for more than 5 minutes to carry out the next impact, a complete impact test usually takes 1 hour.
For every transformer, we prepare and issue a test report in compliance with IEC 60076 standards. In addition to routine tests, we also provide type tests and customized tests to fulfill all customer requirements. Our commitment is to deliver safe and reliable solutions that meet the critical needs of our customers.
