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Verification procedure for power frequency high voltage divider
JJG 49% off—1996
Verification procedure for power frequency high voltage divider
Verification procedure for power frequency high voltage divider
Voltage Jivider at Tower FrequencyJJC: 496199G
This verification procedure was approved by the State Technical Commission on May 24, 1995, and took effect on March 24, 1997. Responsible unit: National Commercial Voltage Metering Station
Drafting unit: National Electric Power Metering Station
The drafting unit of the technical provisions of this regulation is responsible for or interpreting. The main authors of this regulation are: Wang Leren (National High School Standard Measurement Station) Chen Cunsheng (Tongjiashang Voltage Meter Station) Meng Jiachao Co-author: Wang Jian (National Commercial Voltage Meter Station) Technical requirements Specifications Verification and inspection methods Initial station results treatment and inspection period Appendix Bridge comparison Comparison method for measuring the electrical coefficient of capacitor 535wwW.bzxz.Net
Verification procedure for power frequency high voltage divider
This procedure is designed for new products, and is used for measuring power frequency voltage with rated voltage kV of 1.H. It can also be used for the determination of power frequency voltage dividers of non-SOH power frequency voltage dividers. This procedure can also be used for reference:
1 Overview
1 Working principle
The commercial high-frequency voltage divider Z is a long-lasting commercial voltage divider that carries a high-voltage arm Z. It quickly generates a low-voltage arm Z or a 2A combination. As shown in 1, the secondary power frequency voltage of the instrument is 2, and there is a ratio X between the and, and the proportional constant K is called the voltage divider ratio:
In the formula, the center and are the effective values (or values) of the secondary voltage and the secondary voltage. For both high and low frequency voltage dividers, the positive voltage divider ratio can be approximately calculated by the impedance meter:
1 Industrial and commercial high-voltage voltage divider original circuit
In order to reduce environmental interference, the secondary high-voltage divider is used with a shielded output and is connected to the measuring instrument. The cable shield is the capacitance between the outer sheath and the core wire and the low-voltage arm of the divider. Therefore, the primary measurement system should be regarded as part of the voltage divider.
2 Classification of power frequency voltage dividers
High and low voltage voltage dividers are made of resistors: resistive voltage dividers, high and low voltage dividers are made of capacitors: high impedance dividers. Low impedance dividers made of resistors and capacitors in parallel or in series are called capacitive voltage dividers.
2 Technical requirements
3 Accuracy of power frequency voltage dividers
[The error of the voltage divider can be defined as follows: KN-K
Where, 2, the error is expressed as a percentage: is the nominal value of the voltage divider ratio: K is the measured voltage divider ratio.
Power frequency voltage dividers are divided into five levels according to the accuracy of the voltage divider ratio: 0.1, 0.2, 0.5, etc. In the following working frequency and working frequency specifications, the error limit formula of each working level is: 4, =+a%
L1 =± 0.03
In the formula, is the accuracy level index of the sub-voltage: the phase displacement of the secondary voltage relative to the secondary voltage. The unit is radian: 1 The rated working voltage of the sub-voltage is 2% to 100%. If the sub-voltage specifies a wider working voltage, it is appropriate. The super-high voltage sub-voltage is allowed to produce its industry accuracy level: 4 insulation strength
1 bottle high voltage sub-voltage under the rated working frequency, can withstand 1.1 times the rated voltage and 1m withstand voltage test without internal or breakdown phenomenon, the test voltage drops to the working normal range, and can still maintain the original source accuracy unchanged: method, the quality of the sub-voltage analysis, can be used to add a local fault measurement item. Stability
In the environment temperature and temperature range that the technical equipment of the pressure divider is designed to ensure accuracy, the change of the pressure divider ratio error should be less than 1/3 of the agreed error limit corresponding to the accuracy grade. Under the condition of industrial frequency commercial pressure divider, the change of the pressure divider ratio error within 30min should not be greater than 1/3 of the set error limit corresponding to its accuracy grade. Under normal working conditions and service life: the 1-frequency pressure divider still meets all the technical conditions required by this regulation within 2 years.
6 Grounding
1 The high-frequency voltage divider should be equipped with two external grounding terminals on its bottom, which are normally not less than Emm. If the low arm of the voltage divider is not reversely connected to the grounding terminal, a special wiring harness should be provided for the voltage divider to be connected to the public grounding terminal. The circuit structure of the voltage divider principle should be explained on the industrial version of the high-voltage voltage divider. All terminals that need to be connected when in use should be marked on the label. The nameplate should clearly indicate the manufacturing number, model, and output number, H! During the inspection, the commercial voltage, rated frequency (or rated frequency) and reference value of the voltage divider shall be determined based on the actual measured voltage, accuracy grade, and three verification conditions: 8. The ambient temperature during the inspection shall be 10~30°C, and the relative humidity shall be 35%~%, 9. The voltage stability and frequency stability of the power supply shall be such that the deviation of the verification reading shall not be greater than 10% of the allowable error of the voltage divider under inspection, and the actual coefficient of the correction shall not be greater than 5%. The power supply frequency and output voltage points shall cover the operating frequency and voltage range of the voltage divider under inspection, and can be easily assigned to the inspection points within the specified requirements. The actual error of the standard instrument used for the inspection shall be greater than 1% of the set error limit of the voltage divider under inspection; if it cannot be met, a standard with a higher accuracy grade than the voltage divider under inspection may be used, but the measurement result shall be corrected according to its actual error. The power frequency compensation power supply used for calibration should have a value not greater than the error limit of the voltage divider being tested, and the indication error should not be greater than 3%. The resolution should be no less than 1/20 of the error limit of the voltage divider being tested, and the accuracy of the error measuring device should not be lower than Grade 3. The voltage ratio standard that can meet the requirements of calibration includes standard positive voltage transformers and standard voltage dividers. If the voltage ratio of the voltage ratio standard is not equal to the voltage ratio of the high-voltage voltage divider being tested, the voltage ratio can be adjusted to the set value of the voltage divider through a combination of a group of equipment or electronic measuring instruments. 1 The voltage divider under test is within the same range as the voltage divider; the high voltage lead is drawn from the top of the divider, and the angle with the divider is not less than 0; the influence of environmental interference is not greater than 1/0 of the specified voltage divider error limit. If there is no degradation, it is allowed to be calibrated under the actual working environment, but the environmental conditions must be provided in the certificate: 557
Product standard description:
4. Verification items and verification methods
[2 The power frequency high voltage divider in use is based on The following items shall be specified: 12.1 Appearance inspection
12.2 Output ratio accuracy inspection
13. In addition to the inspection items specified in Article 2, the following inspection items shall be added for newly manufactured and repaired power frequency high voltage dividers: 13.1 Dielectric strength inspection
13.2 Thermal stability test
14 Appearance inspection
The appearance of the transformer shall be complete, with oil level indication, the oil level shall meet the marked position, and the nameplate markings shall meet the requirements of the technical conditions. The markings on the terminals shall be complete and correct, and both terminals shall be normal. 15 Insulation strength test
The insulation strength test of the high frequency high voltage divider shall be carried out on the whole divider. The inspection method shall comply with the requirements of "Part 2 Test Light" of 3t1.3-19 High Voltage Test Technical Specification. 16 Accuracy verification of voltage divider
The voltage divider of power frequency high voltage divider is proportional to the voltage divider. This procedure recommends the use of integral method for verification. Five, the workpiece verification method is used to measure the impedance of the high voltage side (belt body) and the low voltage side, and then the calculation method is used to obtain the voltage divider ratio and the accuracy of the voltage divider ratio measurement: the voltage divider ratio measurement uncertainty obtained by the voltage divider verification is calculated with a confidence probability of 0.Double calculation, should not be greater than the allowable error of the installed voltage divider: 1: If the result of the external test set is different from the result of the overall force method, the overall test result shall prevail.
The voltage divider ratio is tested by external compensation method or unbalanced difference method. The compensation method is usually used as shown in Figure 2 or Figure 3. In the figure, T is the test power supply: H and FB are the standard devices, and their voltage ratios are the same as the voltage divider ratio of the voltage divider: 1: The voltage divider is tested, and the frequency voltage divider is 1: The compensation power supply is the lower measurement power supply; G is a three-frequency galvanometer. In order to indicate the working voltage, a variable filter voltmeter can be connected to the primary voltage output terminal of the micro-voltage divider. The accuracy of the voltmeter shall not be lower than Grade 3. The influence of the voltage meter connected to the divider on the proportionality should not be greater than 5% of its error limit. Figure 2 uses the inductor as the selector for the compensation method measurement circuit. Figure 5 uses the voltage divider as the selector for the compensation method. When the voltage divider is used, the compensation value is not half-valued. The negative current of the voltage circuit has no significant effect on the standard instrument and the weak error of the divided instrument. The error limit is 115
. The selected points for verification are 20%, 50%, %, and 10/% of the rated point of the divided instrument. If the technical case of the divider also stipulates other upper and lower voltages, the corresponding preset and lower limit points should also be added. 528
Before verification, carry out at least 2 full voltage rise and fall tests, starting from the limit verification point, and determine the voltage divider ratio error point by point: except for the limit verification point, The error of other calibration points is within the range of 1% of the measured value. If the compensation voltage is proportional to the power supply voltage, the proportional error value of the compensation current indication is proportional to the set difference, and the upper and lower components of the indication are the measured phase shift. If there is sufficient experimental data to prove that the error of the tested device is proportional to the working voltage change (voltage coefficient) within the error limit, the number of overall calibration points can be reduced. The method of measuring the relationship between the change in the value of the low impedance voltage and the working voltage by the bridge comparison method can be used in accordance with the requirements of this regulation. There are multiple voltage divider ratios under the control of the bed divider, The above method is a verification test for the tested voltage divider.
17 Thermal qualitative test
Apply 8% of the rated working voltage to the tested voltage divider to ensure that this voltage is maintained. No abnormal phenomenon should occur during the test. Then, determine the voltage divider ratio according to Article 16. The determination result should meet the requirements of the accuracy level of the tested voltage divider. 5. Processing of verification results and verification cycle
18 After the verification is completed, the data obtained at each verification point are integrated. After the peak error of the standard instrument is corrected, the rising and falling values are averaged. The obtained data are normalized according to 110 of the error limit of the tested voltage divider ratio (including phase shift characteristics). It is determined whether there is a certain error from the point of interest. The normalized data is used as the deduction. 19 Test the voltage divider ratio of all tested points of the voltage divider. According to formula (3), if the error is not found in formula (4), the recognition of the regulation is If the difference is within the range of the average and the phase difference does not exceed the range of formula (S), the voltage ratio accuracy control is qualified. For power-frequency high-voltage voltage dividers with equal voltage ratios, only after all the voltage ratios are calculated can the accuracy level of the tested voltage divider be determined.
20 For power-frequency high-voltage voltage dividers that have been regularly inspected, if the appearance inspection and voltage ratio accuracy inspection are qualified, the inspection certificate can be issued. Newly manufactured and repaired power-frequency high-voltage voltage dividers must also pass the thermal explosion strength test and the qualitative test before they can be issued the qualification certificate. The inspection results of all control items should be listed in the inspection certificate. For three-phase commercial voltage dividers inspected under specific environmental conditions, the inspection environment should be doubled on the certificate. For example, the inspection environment should be doubled on the certificate. For example, when the rated voltage is changed, the test data of the partial inspection points should be changed. The measurement basis and measurement results of the voltage ratio coefficient of the tested voltage should be explained on the certificate. 21 If the inspected high-voltage divider has unqualified verification items, and after the repair period, it still cannot meet the requirements of the original technical conditions, but can meet the new technical requirements of other enterprises after downgrading, it is allowed to be downgraded to the decommissioned level. 2 If the technical specifications of the software and software divider fail the verification, the inspection result notice can be issued. In addition to the verification data listed in Article 2), it also explains the unqualified items and unqualified related contents. 23 The verification period of the high-voltage divider is 3 years. Appendix: Measuring the voltage coefficient of high-voltage capacitors by the voltage comparison method. The high-voltage bridge is an AC instrument for measuring the amplitude ratio and phase difference of industrial frequency current. It can be divided into three types in structure 1: passive current comparator type, active current comparator type. When the test object is a capacitor, the measured value is related to the test object's capacitance (consumption factor 1) and the capacitance and dielectric loss of the standard device. There is the following relationship: .34
In the formula, the capacitance of the capacitor is the measured value, D is the dielectric loss factor of the bridge, and the capacitance of the compressed gas capacitor and the dielectric loss factor can be compared. By comparing the two, the relationship between the test object's capacitance and the dielectric loss factor can be obtained. It can be expressed as: ac, x In the formula, x,,, are the capacitance and dielectric coefficient of the sample under the quasi-voltage. X, and, are the capacitance ratio and dielectric coefficient of the sample under the quasi-voltage. In addition to measuring the voltage coefficient of the capacitor, the voltage coefficient of other impedance components can also be measured by the bridge comparison method.
In the formula, ,, are the capacitance and dielectric coefficient of the sample under the quasi-voltage! X, and, are the capacitance ratio and dielectric coefficient of the sample under the quasi-voltage!
In addition to measuring the voltage coefficient of the capacitor, the voltage coefficient of other impedance components can also be measured by the bridge comparison method.
In the formula, ,, are the capacitance and dielectric coefficient of the sample under the quasi-voltage! X, and, are the capacitance ratio and dielectric coefficient of the sample under the quasi-voltage!
In addition to measuring the voltage coefficient of the capacitor, the voltage coefficient of other impedance components can also be measured by the bridge comparison method.
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