With the development of China's power industry and the continuous expansion of power grids, in order to ensure the safe and stable operation of electrical equipment and power equipment, it is necessary to pay attention to the reliability of its insulation. The accuracy of the impulse voltage divider can determine the reliability of the relevant equipment. The role of the impact voltage divider is mainly used to test the waveform and peak value of the experimental impulse test of electrical equipment. With the universality of China's and international exchanges, in order to promote the smooth import and export of electrical products in China, China needs to strengthen the study of the impact voltage test in order to clarify the performance of electrical products. According to the voltage standard of China's power system distribution network, its withstand voltage is 60KVkV and 75KVkV, and the impact voltage divider is mainly used for the impulse voltage test of high-voltage power equipment, so it needs to meet the impact voltage test of China's power system distribution network. If required, the impulse voltage generator needs to be higher than 100kVKV. In related experiments, it is necessary to regulate according to national standards, that is, the use of standard lightning waves and operational waves, without the need for higher requirements. For impact potentiometers that are not used in actual applications but are used in related research, other calibration methods can be used and cannot be based on national standards. If there is no lightning cut in the calibration content, the protection of the waist is due to the proportional conversion performance of the shock divider. According to the corresponding calculation, it can be concluded that if the response time and the superimposed oscillation amplitude can meet the requirements of the lightning shock wave, it can be corrected. When the impulse voltage signal band exceeds 0.5 MHz, if the impulse divider has a measurement accuracy greater than 1%, it must meet a bandwidth of at least 5 MHz. The impedance and capacitance existing in the coaxial cable will affect the signal measurement error. Since the parameters of different cables are not the same, the coaxial cable should not be separately tested and should be attached to the impact voltage divider. On the unified check. In addition, in order to enable perfect maintenance of the impact voltage divider, it is necessary to specify the characteristic impedance. Due to the production characteristics of the impact voltage divider, there is no standard series of partial pressure ratios, and even some impulse voltage dividers do not clearly indicate the rated partial pressure ratio. However, because the error requires a nominal value, the impact voltage divider must clearly indicate the nominal partial pressure ratio. The partial pressure ratio error of a common voltage divider is mainly expressed as a percentage, and there is also an indication of the accuracy level. However, in order to be able to make the expression more accurate, it is necessary to express it in an accuracy level manner, mainly because the error of the impact voltage divider is related to the voltage, the signal, and the like. In the past, it was mainly expressed in terms of percentages. Therefore, due to the influence of traditional expression methods, there are currently many more voltage dividers expressed as percentages. Because of the objectivity of the calibration, the percent representation method and the accuracy level representation method do not affect the calibration results. It is better for the staff to mark the contents of the high pressure ratio parameter on the nameplate of the impulse divider, which can be more convenient in subsequent operations. The impact voltage dividers used in the laboratory, the impact measurement oscilloscope and the impact peak voltmeter are the components of the secondary measurement of the shock voltage divider. Since the impact measurement oscilloscope and the impact peak voltage meter belong to the secondary instrument, since the voltage does not exceed 2000V, the output voltage of the impact voltage divider does not exceed this range. According to the corresponding standards, when the total peak measurement error does not exceed 3%, the error in the skin shock voltage divider cannot exceed 1%. According to the corresponding requirements, the partial pressure ratio error cannot exceed 1% in the shock divider used in the experimental middle school. And in the actual impact voltage divider, its partial pressure ratio is not based on a clear standard, so it is mainly based on the actual partial pressure ratio and the rated partial pressure ratio of the deviation can not exceed 1%. If the stability of the shock voltage divider is relatively good, a calibrated value should be used as the rated value, but it must be subjected to a corresponding stability test, and the value can be adopted only after passing through. Since the response time has a large error impact on the peak value of the lightning wave, if the response time is known, it can be corrected according to the corresponding formula. It can be understood through calculation that when the corresponding time is 100ns, the waveform peak will be converted to 2.2μs 1, interpretation of calibration conditions Because there are stray capacitances in the impulse divider, and these capacitors can increase the corresponding time, it will affect the voltage divider ratio and cause it to change. By pulling away the distance, the effect of the capacitance can be effectively reduced, that is, only the capacitance to ground is retained. If the voltage divider is fixed, its capacitance will not change. Metal foil as a ground loop can reduce the impedance of the ground loop wave and reduce the calibration error. During verification, the high voltage leads should be kept in the same or nearly the same state. 2. Standard voltage divider When using the comparison method for verification, it is mainly through the comparison of the standard voltage divider and the voltage divider under test, that is, by applying the same voltage to the two voltage dividers. However, due to the problem of high voltage, it is impossible to meet the conditions for applying uniform voltage at the same time. In this case, actual voltages exceeding 1/5 of the rated voltage can be used for testing. With the comparison method, the measurement error must not exceed 1/3, which meets the requirement of class 0.2. 3, digital recorders and oscilloscopes Digital recorders and oscilloscopes should take 10 times the bandwidth, that is, 100MHz, for the digital recorder sampling point needs more than 12 bits, and the use of 1/5 range calculation, so as to meet the calibration requirements. 4, DC ohmmeter and capacitance measurement instrument Although the parameters of capacitance and resistance can not determine the partial pressure ratio, but can become a reference value. The partial pressure ratio error of the test sample must be 1%, so the measurement error of the reference value control must also be 1%. 1. Partial pressure ratio measurement method There are two main methods for measuring the partial pressure ratio. One of them is to calculate the parameters of the components. However, due to the influence of environmental factors, there will be large errors. The other is the measurement using a measuring device, which has a large difference between the frequency and voltage used and the impulse voltage. In the partial pressure ratio measurement, it is necessary to use a voltage waveform and a peak voltage close to the actual value. 2, calibration interval According to the research on the impact voltage divider at home and abroad, it can be found that more impact voltage dividers are in stable operation. And if the impulse divider passes the calibration, the calibration interval can be extended by 5 years. To sum up, China's electric power industry has developed rapidly, and the scale of power grids has been expanding. People's needs are constantly increasing. To ensure the safe operation of electric equipment and electric equipment, we must pay full attention to the reliability of electric insulation and promote our electrical products. The import and export, to strengthen the study of the impact voltage test, so as to improve the performance of electrical products, hope to help relevant workers through this article. Guangzhou Bolei Electronic Technology Co., Ltd. , https://www.nzpal.com
