Some standard content:
National Metrology Verification Standard of the People's Republic of China J.IG 970—2002
Transformers Turn Ratio Test Sets2002 -- Issued on May 24
Implementation on August 24, 2002
Issued by the General Administration of Quality Supervision, Inspection and Quarantine J.IG 970-—2002
Verification Regulation nf
Transformers Turn Ratio Test SetsJJG 970—2002
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine on May 24, 2002, and will be implemented on August 24, 21H)2.
Responsible unit: Jinyin AC Electricity Measurement Technical Committee Main drafting unit: China Academy of Sciences Participating drafting unit:
Xiyangzhong Measurement Technology Co., Ltd.
This regulation is entrusted to the National AC Electricity Measurement Technical Committee to interpret this regulation Main drafter:
He Xiaobing
Participating drafter:
J.IG 970---2002
(China Academy of Planning and Science)
(Ministry of Science and Technology of Yangzhongchuan) [China Academy of Planning and Science]
Scope·
Metrological performance requirements
Pressure measurement
Main functions
Sensitivity
Standard deviation
General technical requirements·
Insulation, secondary voltage
5 Measuring instrument control
Verification conditions
Verification items,
Verification method
Verification results
Verification adjustment period·
J.IG 570-2002
Appendix A Data format for digital transformer ratio bridge certificate
Data format for type EF-24 transformer ratio bridge certificate
Appendix
Appendix EF-35 transformer ratio bridge certificate data format Appendix 1 Original record format for digital transformer ratio bridge Appendix EF-2.1 Original record format for transformer ratio bridge -- Appendix FI-35 original record format for transformer ratio bridge (1)
1 Scope
LIC 970-2002
Verification procedure for transformer ratio bridge
This procedure applies to the initial verification, subsequent verification and in-service inspection of pointer-type and digital transformer ratio bridges, transformer ratio testers and transformer ratio testers [hereinafter collectively referred to as transformer ratio bridges). 2 Overview
The transformer ratio corrector is a special instrument for measuring the transformer ratio. It can be used to measure the transformation ratio value and transformation ratio error of single-phase and two-phase transformers and medium-voltage transformers. Generally speaking, there are two types of transformer ratio correctors: pointer-type dynamic bridge and digital display automatic bridge. Their measurement functions are basically the same, and they both have the functions of measuring transformation ratio value, transformation ratio error value and connection group. 3 Metrological performance requirements
3.1 Accuracy level
The accuracy level of the ratio bridge is divided into two levels: 0.05, 0.1, and 0.2. The maximum allowable error of each level shall not exceed the provisions of Table 1. The instrument is allowed to output different accuracy levels according to different transformation ratio ranges. Table 1 Maximum allowable error of transformer ratio bridge Accuracy Category Allowable error 3.2 Main functions 3.2.1 Transformation ratio indicator Each level of transformer ratio bridge should have a ratio measurement indicator with corresponding measuring range. 0.2 level
3.2.1.1 The minimum step value of the pointer-type bridge ratio measuring dial shall not be greater than 1/5 of the maximum allowable error of each level. 3.2.1.2 The last digit display value of the digital display type voltage correction ratio measuring display shall not be greater than 1/
The error indicator
When measuring the ratio, the ratio error and the error indicator can be read at the same time. The measurement range should not exceed ±2%, and the absolute value of the indication error shall not be greater than 1% of the absolute value of the maximum allowable error of the voltage. The minimum resolution of the error indicator shall not be greater than 0.ot%
3.2.3 Connection group test function
The voltage ratio analyzer should have the function of testing different differential connection groups of transformers and the corresponding switches, and can test the connection group of reversible transformers.
3.2.1 Tap function
JIG 470—2002
The transformer ratio bridge has the function of testing tap terminals, which can be used to test any tap transformer: 3.3
3.1 Digital test bridge: The bridge is rated for operation and is used in a certain test cell. When the bridge is half-torn, the total change is within the maximum value recorded by the test disk, and the increase or decrease pointer of the instrument should not be less than 3.2 Digital subtraction bridge: Use a standard instrument to select the correct value: When the value is within 5% of the standard instrument’s value without any error, the total value will change by about 3.4 Standard reduction
The transformer ratio bridge measurement indication value should be less than 1% of the maximum allowable absolute value! Technical requirements for use
4. "Outer specifications
The transformer is half-solid and reliable, and the instrument panel shell is obviously marked with heat damage. The markings of various frequencies and forces should be clear and consistent. The disconnection books should be opened or closed with lights, and the beams should be flexible. The electrical stack or external workers should have production and sales brands: the internal inspection should be in accordance with the US standards, the design and construction should be complete, and the external electrical correction test should be almost the same as the external electrical appliances. The test time is 1000 hours, and the load resistance test is less than 1m. 5. Measuring instrument control
Measuring instrument control includes: efficiency verification, gate verification and transformer inspection. 5.1 Verification conditions
5.t. General equipment
5.1.1.1 Transformer ratio bridge standard (or induction transformer) and standard transformer selection.
5.1.1.? Use the transformation ratio standard [or induction transformer] to perform single-phase error detection on the bridge. The maximum allowable error absolute value of the transformer standard (or induction transformer) should not exceed 15 of the maximum allowable error absolute value of the tested bridge, and the minimum division value should not exceed 1 of the maximum allowable error absolute value of the tested bridge! 5.1.1.3 Use the two-phase standard voltage transformer to verify the phase sequence and connection group of the bridge. The two-phase standard voltage sensor should at least include Y/u, Y/y6, ao, /ae, Y/ls, Y/al, Dy, D/ll and other application groups, and its maximum allowable error absolute value should not be less than 1/5 of the maximum allowable error value of the bridge under test. 5.1.1.4 Determination of bridge insulation voltage positioner: 1000V megameter, accuracy level 10. 5.1.1.5 Withstand voltage tester: Use equipment certified by the tester, its withdrawal capacity should be not less than 0.5kVA, the basic error of the daily measurement should be better than +3,
, 1 environment standard
5.: 21 environment tracking: 20+5) ℃; accuracy: 133.-803%. 5.1.2.2 Electrical
: 220=10! V: Amount rate: (5011) H: Kuantan F5%5.2 The price is
The price of these items H is not shown in Table 2.
Check the item day
Change ratio
Your flow inquiry point
Lost head
Leyuan Mountain
JG 970- 2002
Table 2 Items to be calibrated
Time to be calibrated
Post-calibration
: Item "cannot be done", "one" indicates the point of learning, "," does not indicate the pre-cooling after the treatment 5.3 Calibration method
5.3.1 Appearance inspection
The appearance inspection of the transformer ratio convex bridge shall comply with Article 4.1 of the small specification.
5.3.2 The calibration of the two-phase transformer ratio bridge can be divided into single-pole calibration and calibration part. Single-phase calibration includes ratio indication, differential indicator, tap changer, standard deviation Verification: Three-phase verification includes the verification of the order and connection group.
5.3.3 Single-phase verification
Under normal circumstances, select phase B for verification: See the wiring diagram of the verification in Figure 1. S.3.3.1 Degree of sensitivity verification
1) For the pointer-type transformer, under rated working voltage, set the transformer ratio to the maximum state, and select a transformer ratio near the upper limit of the measured value. When the transformer ratio is balanced, adjust the transformer ratio or error plate to the position of the transformer ratio under test. The sensitivity of the transformer ratio is in accordance with the provisions of Section 3.3.1) For digital display type variable ratio bridge, the bridge ratio is selected with the upper limit in the inspection, and the ratio value is set to 3
MG970-2002
1. When the voltage is stable, adjust the ratio selector, the bridge ratio and the error display value should change accordingly, and the H-range index should meet the requirements of the program 3.3. 2 requirements.5.3.3.2 Small value test of transformer ratio
I) Connect the group circuit according to the diagram, set the switch of the transformer to "A", reverse the switch to "U" minus "12", set the error dial to "\", adjust the sensitivity of the zero indicator to the minimum, and turn on the power for more than 10 minutes (according to the requirements of the book. After that, adjust the sensitivity of the zero indicator to the zero position. At the same time, adjust the zero position knob to balance the zero position:
2) In the calibration pointer type, use a transformer! The ratio measuring plate of the ratio standard instrument on the testing bridge is used for the correction of the tested circuit with a magnification switch. The first plate to be used for the ratio measurement is always used to ensure that the voltage is steadily increased to the specified value during the entire calibration process. For each calibrated point, adjust the ratio standard indication to make the indication zero. The indication of the point is calculated using the formula (1): _ K- × -
In the formula: , the relative error of the calibrated point of the tested bridge: K, - indication of the ratio scale (standard ratio value); I, indication of the ratio measurement plate of the tested bridge (t)
3) When testing the digital display circuit: adjust the indication of the ratio standard instrument on the ratio bridge testing device to each calibration point. The relative error of the tested bridge ratio display value can be read from its error display after taking the "negative" value. The ratio value can be directly read on the ratio display of the bridge, and then the sum and difference of the points can be calculated according to formula (1). 4) The selection of the calibration points can refer to the table in the appendix, and the test points used by the band can be added according to the requirements of the application. Other calibration points can be selected, but they should be relatively comprehensive. 5.3.3.3 Standard deviation determination
For three-pin transformer ratio testers, the standard deviation verification is the same as the ratio value verification method described in Articles 3 and 4 of this regulation. Select the point with the maximum error in the indication of the tested bridge ratio as the calibration point. Under the condition that other parameters remain unchanged, reverse the measured value of the tested bridge ratio. Repeat the calibration more than 5 times. For digital transformer ratio bridge, it should be re-operated 5 times. Calculate the standard deviation of the tested bridge according to formula (2): 1(- x)
Test voltage: >, the standard deviation of the tested bridge; actual value of a single calibration:
: ——, the average value of the actual value of multiple calibrations: n——calibration times.
5.3.3.4 Error calibration
1) For the calibration bridge, firstly adjust the error plate of the bridge to be tested, and set the ratio measuring plate to (K1): the current ratio standard reading of the bridge calibration device to balance it, and record the reading of the ratio standard K: Then, adjust the error plate of the bridge to be tested to the required calibration point, adjust the ratio standard reading to balance the bridge to be tested, and record the reading of the ratio standard K. The error plate reading error is calculated according to formula (3), and the error plate should be calibrated point by point.
In the formula: ,——error plate reading error: the ratio measuring plate reading of the bridge to be tested (K-1); the error plate reading error:
K. The error plate reading is set to zero: the ratio standard reading (standard ratio value): K. 1. When the error indication is equal to the value of the standard transformer ratio (standard transformer ratio value). : For customers, the final guarantee of the measured circuit is K-10A (3)
2) For the effective display bridge meter, the error display value is obtained by the machine operation screen. In order to verify whether the calculation document is correct, a certain error indication value can be selected for verification. First, set the short-circuit transformer ratio display to 10 (K-10), adjust the transformer ratio standard indication on the transformer ratio bridge verification device, so that the error display of the adjusted transformer ratio is equal to that of the transformer ratio display, write down the reading of the transformer ratio standard K, and then adjust the indication of the transformer ratio standard to make the error display of the tested bridge show more accurate, to verify The reading of the ratio standard is K, and the error of the minimum value of the difference is calculated according to formula (3). 5.3.3.5 Tap detection
1 For the bridge to be tested with taps, the taps should be calibrated. The ratio standard on the transformer ratio bridge calibration device is used to calibrate the taps point by point. The error of the minimum value of the tap is calculated according to formula (1!
2) For digital type circuits, the tap value is calculated by the single chip microcomputer. In order to verify the correctness of the calculation formula, 1 to 2 taps can be checked and adjusted individually: 5.3.4 Two-phase calibration
JJG 970—2002
Standard transformer bridge calibration installation, two single-phase standard medium voltage five-phase transformers are used to form a three-output standard transformer mutual energy group, and the transformer ratio is measured and connected in the cabinet, refer to Figure 2 for wiring. In the phase level, CA, and 5.1.1.3 clauses, the sound correction is carried out separately. -2 transformation ratio values can be set: the error indicator of the detected bridge in the relative error case receives a "negative" reading. It can also be directly signed by the transformation ratio display 1 to continue to climb the north value: then use the formula () to calculate the phase difference. Ao
Three sample standards
Electric bridge five sea devices
Figure 2-1 shows the connection circuit of the inspection
5.3.5 Absolute voltage test
Take the exposed test terminal of the inspection bridge as one end and the external grounding terminal as the other end, and use a 1000V megohmmeter to test, which should comply with Article 4.2 of this regulation. 5,3,6 Withstand voltage test
The withstand voltage test should be carried out on a test device that meets the requirements of Article 4.2 of this regulation, and on the test device of the inspected household. The voltage between the test terminal and the outside is increased steadily to 20V and lasts for 1mjm. The leakage current should be less than 5mA and there should be no breakdown. The bridge should be able to work normally after the test. 5.37 Data processing
Take 1/10 of the allowable error of the inspector as the certificate and make corrections according to the data correction rules. 5.3. Determine whether the inspected bridge is qualified: the data after correction shall prevail. 5.4 Verification result verification
According to the requirements of the final procedure, all verifications must be issued by the Ministry of Electric Power to the qualified transformer. The verification results will not be known until the age of the qualified transformer: and indicate the qualified items.
5.5 Verification period
The verification period of the transformer is generally less than 1 year. Appendix A
J.IG 970—2002
Digital display type transformer ratio bridge certificate data format 1: External inspection: (qualified or not)
Condition: {qualified or not?
Temperature difference display device: (qualified or not)
Ratio display value error
Standard value
Water level error/(%)
2. Insulation resistance:
4. Sensitivity: (qualified or not)
6. Tap display: (qualified or not)
Standard signal
Display value error/(%)
Single phase indication error
Ratio channel
9. Standard differential
Verification conditions
Manganese degree:
JH:970—2002
Centrifugal force:The relative error of the bridge ratio point is: K, -- the indication of the ratio scale (standard ratio value); I, the indication value of the ratio of the bridge ratio measurement base plate (t)
3) When testing the digital display type transformer: adjust the ratio standard on the transformer ratio bridge test device to determine the calibration point. The relative error of the bridge ratio display value can be read from the error display after taking the "negative" value. The value can be directly read from the ratio display of the bridge ratio test device, and then the sum of the points is calculated according to formula (1). 4) The selection of calibration points can refer to the table in the appendix, and the test points used can be added according to the requirements of the application. The calibration points can be selected separately, but they should be more completely covered by the instrument ratio measurement specification 5.3.3.3 Standard deviation determination
For the three-pin transformer ratio test device, the standard deviation calibration is the same as the calibration method of the ratio value described in Articles 3 and 4 of this regulation. Select the point with the maximum error in the indication of the tested bridge ratio as the calibration point. Under the condition that other parameters remain unchanged, reverse the measured value of the tested bridge ratio. Repeat the calibration more than 5 times. For digital transformer ratio bridge, it should be re-operated 5 times. Calculate the standard deviation of the tested bridge according to formula (2): 1(- x)
Test voltage: >, the standard deviation of the tested bridge; actual value of a single calibration:
: ——, the average value of the actual value of multiple calibrations: n——calibration times.
5.3.3.4 Error calibration
1) For the calibration bridge, firstly adjust the error plate of the bridge to be tested, and set the ratio measuring plate to (K1): the current ratio standard reading of the bridge calibration device to balance it, and record the reading of the ratio standard K: Then, adjust the error plate of the bridge to be tested to the required calibration point, adjust the ratio standard reading to balance the bridge to be tested, and record the reading of the ratio standard K. The error plate reading error is calculated according to formula (3), and the error plate should be calibrated point by point.
In the formula: ,——error plate reading error: the ratio measuring plate reading of the bridge to be tested (K-1); the error plate reading error:
K. The error plate reading is set to zero: the ratio standard reading (standard ratio value): K. 1. When the error indication is equal to the value of the standard transformer ratio (standard transformer ratio value). : For customers, the final guarantee of the measured circuit is K-10A (3)
2) For the effective display bridge meter, the error display value is obtained by the machine operation screen. In order to verify whether the calculation document is correct, a certain error indication value can be selected for verification. First, set the short-circuit transformer ratio display to 10 (K-10), adjust the transformer ratio standard indication on the transformer ratio bridge verification device, so that the error display of the adjusted transformer ratio is equal to that of the transformer ratio display, write down the reading of the transformer ratio standard K, and then adjust the indication of the transformer ratio standard to make the error display of the tested bridge show more accurate, to verify The reading of the ratio standard is K, and the error of the minimum value of the difference is calculated according to formula (3). 5.3.3.5 Tap detection
1 For the bridge to be tested with taps, the taps should be calibrated. The ratio standard on the transformer ratio bridge calibration device is used to calibrate the taps point by point. The error of the minimum value of the tap is calculated according to formula (1!
2) For digital type circuits, the tap value is calculated by the single chip microcomputer. In order to verify the correctness of the calculation formula, 1 to 2 taps can be checked and adjusted individually: 5.3.4 Two-phase calibration
JJG 970—2002
Standard transformer bridge calibration installation, two single-phase standard medium voltage five-phase transformers are used to form a three-output standard transformer mutual energy group, and the transformer ratio is measured and connected in the cabinet, refer to Figure 2 for wiring. In the phase level, CA, and 5.1.1.3 clauses, the sound correction is carried out separately. -2 transformation ratio values can be set: the error indicator of the detected bridge in the relative error case receives a "negative" reading. It can also be directly signed by the transformation ratio display 1 to continue to climb the north value: then use the formula () to calculate the phase difference. Ao
Three sample standards
Electric bridge five sea devices
Figure 2-1 shows the connection circuit of the inspection
5.3.5 Absolute voltage test
Take the exposed test terminal of the inspection bridge as one end and the external grounding terminal as the other end, and use a 1000V megohmmeter to test, which should comply with Article 4.2 of this regulation. 5,3,6 Withstand voltage test
The withstand voltage test should be carried out on a test device that meets the requirements of Article 4.2 of this regulation, and on the test device of the inspected household. The voltage between the test terminal and the outside is increased steadily to 20V and lasts for 1mjm. The leakage current should be less than 5mA and there should be no breakdown. The bridge should be able to work normally after the test. 5.37 Data processing
Take 1/10 of the allowable error of the inspector as the certificate and make corrections according to the data correction rules. 5.3. Determine whether the inspected bridge is qualified: the data after correction shall prevail. 5.4 Verification result verification
According to the requirements of the final procedure, all verifications must be issued by the Ministry of Electric Power to the qualified transformer. The verification results will not be known until the age of the qualified transformer: and indicate the qualified items.
5.5 Verification period
The verification period of the transformer is generally less than 1 year. Appendix A
J.IG 970—2002
Digital display type transformer ratio bridge certificate data format 1: External inspection: (qualified or not)
Condition: {qualified or not?
Temperature difference display device: (qualified or not)
Ratio display value error
Standard value
Water level error/(%)
2. Insulation resistance:
4. Sensitivity: (qualified or not)
6. Tap display: (qualified or not)
Standard signal
Display value error/(%)
Single phase indication error
Ratio channel
9. Standard differential
Verification conditions
Manganese degree:
JH:970—2002
Centrifugal force:The relative error of the bridge ratio point is: K, -- the indication of the ratio scale (standard ratio value); I, the indication value of the ratio of the bridge ratio measurement base plate (t)
3) When testing the digital display type transformer: adjust the ratio standard on the transformer ratio bridge test device to determine the calibration point. The relative error of the bridge ratio display value can be read from the error display after taking the "negative" value. The value can be directly read from the ratio display of the bridge ratio test device, and then the sum of the points is calculated according to formula (1). 4) The selection of calibration points can refer to the table in the appendix, and the test points used can be added according to the requirements of the application. The calibration points can be selected separately, but they should be more completely covered by the instrument ratio measurement specification 5.3.3.3 Standard deviation determination
For the three-pin transformer ratio test device, the standard deviation calibration is the same as the calibration method of the ratio value described in Articles 3 and 4 of this regulation. Select the point with the maximum error in the indication of the tested bridge ratio as the calibration point. Under the condition that other parameters remain unchanged, reverse the measured value of the tested bridge ratio. Repeat the calibration more than 5 times. For digital transformer ratio bridge, it should be re-operated 5 times. Calculate the standard deviation of the tested bridge according to formula (2): 1(- x)
Test voltage: >, the standard deviation of the tested bridge; actual value of a single calibration:
: ——, the average value of the actual value of multiple calibrations: n——calibration times.
5.3.3.4 Error calibration
1) For the calibration bridge, firstly adjust the error plate of the bridge to be tested, and set the ratio measuring plate to (K1): the current ratio standard reading of the bridge calibration device to balance it, and record the reading of the ratio standard K: Then, adjust the error plate of the bridge to be tested to the required calibration point, adjust the ratio standard reading to balance the bridge to be tested, and record the reading of the ratio standard K. The error plate reading error is calculated according to formula (3), and the error plate should be calibrated point by point.
In the formula: ,——error plate reading error: the ratio measuring plate reading of the bridge to be tested (K-1); the error plate reading error:
K. The error plate reading is set to zero: the ratio standard reading (standard ratio value): K. 1. When the error indication is equal to the value of the standard transformer ratio (standard transformer ratio value). : For customers, the final guarantee of the measured circuit is K-10A (3)
2) For the effective display bridge meter, the error display value is obtained by the machine operation screen. In order to verify whether the calculation document is correct, a certain error indication value can be selected for verification. First, set the short-circuit transformer ratio display to 10 (K-10), adjust the transformer ratio standard indication on the transformer ratio bridge verification device, so that the error display of the adjusted transformer ratio is equal to that of the transformer ratio display, write down the reading of the transformer ratio standard K, and then adjust the indication of the transformer ratio standard to make the error display of the tested bridge show more accurate, to verify The reading of the ratio standard is K, and the error of the minimum value of the difference is calculated according to formula (3). 5.3.3.5 Tap detection
1 For the bridge to be tested with taps, the taps should be calibrated. The ratio standard on the transformer ratio bridge calibration device is used to calibrate the taps point by point. The error of the minimum value of the tap is calculated according to formula (1!
2) For digital type circuits, the tap value is calculated by the single chip microcomputer. In order to verify the correctness of the calculation formula, 1 to 2 taps can be checked and adjusted individually: 5.3.4 Two-phase calibration
JJG 970—2002
Standard transformer bridge calibration installation, two single-phase standard medium voltage five-phase transformers are used to form a three-output standard transformer mutual energy group, and the transformer ratio is measured and connected in the cabinet, refer to Figure 2 for wiring. In the phase level, CA, and 5.1.1.3 clauses, the sound correction is carried out separately. -2 transformation ratio values can be set: the error indicator of the detected bridge in the relative error case receives a "negative" reading. It can also be directly signed by the transformation ratio display 1 to continue to climb the north value: then use the formula () to calculate the phase difference. Ao
Three sample standards
Electric bridge five sea devices
Figure 2-1 shows the connection circuit of the inspection
5.3.5 Absolute voltage test
Take the exposed test terminal of the inspection bridge as one end and the external grounding terminal as the other end, and use a 1000V megohmmeter to test, which should comply with Article 4.2 of this regulation. 5,3,6 Withstand voltage test
The withstand voltage test should be carried out on a test device that meets the requirements of Article 4.2 of this regulation, and on the test device of the inspected household. The voltage between the test terminal and the outside is increased steadily to 20V and lasts for 1mjm. The leakage current should be less than 5mA and there should be no breakdown. The bridge should be able to work normally after the test. 5.37 Data processing
Take 1/10 of the allowable error of the inspector as the certificate and make corrections according to the data correction rules. 5.3. Determine whether the inspected bridge is qualified: the data after correction shall prevail. 5.4 Verification result verificationbZxz.net
According to the requirements of the final procedure, all verifications must be issued by the Ministry of Electric Power to the qualified transformer. The verification results will not be known until the age of the qualified transformer: and indicate the qualified items.
5.5 Verification period
The verification period of the transformer is generally less than 1 year. Appendix A
J.IG 970—2002
Digital display type transformer ratio bridge certificate data format 1: External inspection: (qualified or not)
Condition: {qualified or not?
Temperature difference display device: (qualified or not)
Ratio display value error
Standard value
Water level error/(%)
2. Insulation resistance:
4. Sensitivity: (qualified or not)
6. Tap display: (qualified or not)
Standard signal
Display value error/(%)
Single phase indication error
Ratio channel
9. Standard differential
Verification conditions
Manganese degree:
JH:970—2002
Centrifugal force:4 Two-phase calibration
JJG 970—2002
Standard transformer bridge calibration installation, two single-phase standard medium voltage five-phase transformers are used together to form a three-output standard transformer group, and the transformation ratio is determined in the cabinet, and the connection is determined as shown in Figure 2. Under the phase level, CA, and CA, the sound correction of the provisions of 5.1.1.3 is carried out separately. The error indicator of the detected bridge error in the case of 1-2 transformation ratios can be determined: the error indicator of the detected bridge error receives a "negative" reading. It can also be directly used to calculate the value of the transformation ratio display 1: Then the formula () is used to calculate the phase difference. Ao
Three sample standards
Electrical device
Figure 2-1 Schematic diagram of the test circuit
5.3.5 Insulation test
Take the exposed test terminal of the test bridge as one end and the external ground terminal as the other end, and use a 1000V megohmmeter to test. It should meet the requirements of Article 4.2 of this regulation. 5.3.6 Withstand voltage test
The withstand voltage test should be carried out on a test device that meets the requirements of Article 4.2 of this regulation. The voltage between the test terminal of the tested unit and the external ground terminal should be increased to 20V and last for 1mjm. The leakage current should be less than 5mA, and there should be no breakdown phenomenon. After the test, the bridge should be able to work normally. 5.37 Data processing
Take 1/10 of the allowable error of the tester as the standard and make corrections according to the data correction rules. 5.3. Determine whether the tested bridge is qualified: the effective data after verification shall prevail. 5.4 Verification results
According to the requirements of the program, all the verified bridges must be issued a verification certificate by the Ministry of Power Supply. The verification results will not be issued until the age of the verification: and the qualified items shall be noted.
5.5 Verification cycle
The verification cycle of the transformer ratio bridge is generally less than 1 year. Appendix A
J.IG 970—2002
Digital display transformer ratio bridge certificate data format 1: External inspection: (qualified or not)
Condition: {qualified or not?
Temperature difference display: (qualified or not)
Ratio display value error
Standard value
Water level error/(view)
2. Insulation resistance:
4.Sensitivity: (whether it is qualified)
6.Tap display: (whether it is qualified)
Standard signal
Display value error/(%)
Single phase display error
Transformation ratio
9.Standard reduction
Verification conditions
Manganese content:
JH:970—2002
Mixed content:4 Two-phase calibration
JJG 970—2002
Standard transformer bridge calibration installation, two single-phase standard medium voltage five-phase transformers are used together to form a three-output standard transformer group, and the transformation ratio is determined in the cabinet, and the connection is determined as shown in Figure 2. Under the phase level, CA, and CA, the sound correction of the provisions of 5.1.1.3 is carried out separately. The error indicator of the detected bridge error in the case of 1-2 transformation ratios can be determined: the error indicator of the detected bridge error receives a "negative" reading. It can also be directly used to calculate the value of the transformation ratio display 1: Then the formula () is used to calculate the phase difference. Ao
Three sample standards
Electrical device
Figure 2-1 Schematic diagram of the test circuit
5.3.5 Insulation test
Take the exposed test terminal of the test bridge as one end and the external ground terminal as the other end, and use a 1000V megohmmeter to test. It should meet the requirements of Article 4.2 of this regulation. 5.3.6 Withstand voltage test
The withstand voltage test should be carried out on a test device that meets the requirements of Article 4.2 of this regulation. The voltage between the test terminal of the tested unit and the external ground terminal should be increased to 20V and last for 1mjm. The leakage current should be less than 5mA, and there should be no breakdown phenomenon. After the test, the bridge should be able to work normally. 5.37 Data processing
Take 1/10 of the allowable error of the tester as the standard and make corrections according to the data correction rules. 5.3. Determine whether the tested bridge is qualified: the effective data after verification shall prevail. 5.4 Verification results
According to the requirements of the program, all the verified bridges must be issued a verification certificate by the Ministry of Power Supply. The verification results will not be issued until the age of the verification: and the qualified items shall be noted.
5.5 Verification cycle
The verification cycle of the transformer ratio bridge is generally less than 1 year. Appendix A
J.IG 970—2002
Digital display transformer ratio bridge certificate data format 1: External inspection: (qualified or not)
Condition: {qualified or not?
Temperature difference display: (qualified or not)
Ratio display value error
Standard value
Water level error/(view)
2. Insulation resistance:
4.Sensitivity: (whether it is qualified)
6.Tap display: (whether it is qualified)
Standard signal
Display value error/(%)
Single phase display error
Transformation ratio
9.Standard reduction
Verification conditions
Manganese content:
JH:970—2002
Mixed content:
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