JJG 780-1992 AC digital power meter JJG780-1992 standard download decompression password: www.bzxz.net
This regulation is applicable to single-phase or three-phase digital display power meters used for measuring AC active power, which are newly produced, in use and after repair, and AC power converters used with DC digital voltmeters.

Verification procedure for AC digital power meter
1IG 7801992
Verification procedure for AC digital power meter
Verification for AeDigital
Powermeter
I.IG 780—1992
This regulation was approved by the State Technical Commission on February 15, 1942, and came into effect in January 13, 1993. Authorized unit: Institute of Aeronautics and Astronautics, Ministry of Aeronautics and Astronautics Drafting unit: Institute of Aeronautical Industry, Chinese Academy of Planning and Design Sciences
The supporting provisions of this regulation shall be interpreted by the drafting unit. The main drafters of this regulation:
Qian Zhonglun
Jiang Xiuye
National Institute of Metrology)
Jiaotong China Institute of Metrology)
Additional drafters:
And Song Gao
(Regional Metrology Station of Ministry of Aeronautics and Astronautics)
Technical requirements.
Verification conditions
Risk determination items H
Difficult to determine Method
（—）External inspectionbzxZ.net
、）Determination method of single-phase digital power meter (II)Determination of basic error of digital dynamic meter (IV)Determination method of other items
VI. Processing of verification results
VII. Verification cycle
Appendix 1 Original record
Appendix 2 Supplementary verification method of single-phase digital power meter
Verification procedure of AC digital power meter
This procedure applies to the newly produced and used single-phase or two-phase digital power meter with AC power output, and the AC power converter with digital voltage. The AC voltage of the micro-measurement active power, the current rate range is 4→1H, and the reference error of the controlled meter is not less than 2×10=（live 4）. The speed meter (hereinafter referred to as the power meter) is an AC power meter with an average power. The input quantity is the voltage but the received power is the current. It uses the measurement diagram or frame. The AC voltage and current are measured by the AC digital power meter, and the voltage and current are measured by the DC digital power meter. The power is measured by the AC digital power meter, and the voltage and current are measured by the DC digital power meter. The power is measured by the DC digital power meter, and the DC digital power meter usually directly gives the measured power indication Pn. When the digital power meter is a sand meter, the power is measured by the DC digital power meter. When the power is turned on, the measured power is converted into a voltage component, which is an AC power converter. At this time, the digital power meter provides the user with the indication value, which is the power factor P, expressed as:
P=KrU,
where K is the standard pulse conversion coefficient of a power converter. A digital power meter or a power converter can have a frequency-generated pulse or code pulse output suitable for measurement or remote control. The digital power meter can also measure the frequency-related factors (voltage, power factor, power factor, etc.) related to the received power! Their calibration should be carried out according to relevant regulations. This procedure does not include the contents related to the calibration of these parts.
2 The digital power meter can be single-phase. It can also be multi-phase. This regulation takes into account the multi-phase user's situation. A "three-phase digital power meter" can be composed of two or more single-phase power measurement units. Measurement of three-phase power factor The short result is the sum of the measured results of each power unit. The summation method can be carried out by adding the voltages in the opposite directions, or by performing a total calculation on the digital current and voltage meter. There are two real three power measurement units connected, and the circuit of the three-phase digital power meter is completely alternated with the circuit of the general single-phase power meter or the two-phase power meter.
Figure 2 is a circuit composed of two single-phase power meters to measure the three-phase two-wire power. The power measurement result of one station is the sum of the single-phase measurement results of the two meters, and the accuracy of the measurement result is not affected. 3 is a circuit composed of a single-phase power meter to measure the three-phase two-wire power meter. The power measurement result of one station is the sum of the results of the 740
circuit.
The scanning effect between the single-phase power meters in Figure 3 is not affected by the single-phase meter. The error ratio should be able to be adjusted: In addition, the potential between each single-phase wattmeter and the ground should be insulated. The digital wattmeter or the average power converter must have the same lead and output terminals, and the terminal number markings should be clear. The voltage and current of the national public road should be the same. The other markings of the digital power meter should comply with the provisions of the technical conditions. When there are international industry standards for the requirements for the relevant markings, the relevant technical requirements in the technical conditions of the digital wattmeter should comply with the provisions of these standards. The digital wattmeter must be within the voltage, current limit, and power range. 1.1 The voltage range of digital power meter should be selected from the following series: 15V, 30V 75 (60) V. 100V, 150V, 2V, 40V, 40V, 250V, 6V4.2 The current range of digital power meter should be selected from the following series: 0.1A, 0.25 (0.2)A, 0.54, 1A, 2.5 (2)4, 5A, 10A, 204, 4.3 The power factor range of digital power meter should be selected from the following series: 0~±1, 0-1. 0.5-1, 0-0.2, U--0.1.0-0.05. When the power factor is higher than 100%, the power factor is 0.1~±1. When the factor is within the above range, the accuracy of the digital power meter shall meet all the requirements of the technical conditions of the platform. The power factor range of the power meter is 0~.2.0-0.1.0~0.05. The absolute value of the upper limit of the power factor range is called the rated factor of the power meter. The working power of the digital power meter should be selected from the following series. 15--55H, 40400Hz, 40~1000H, 40~2000H2, 405030Hz, 40~10000H. 741
Among them, the power meter that can be used at a frequency of <565H is called an industrial frequency average power meter. 4.5 Digital power meters can have different electrical and current limits, several engineering power ranges, and they have different accuracy requirements. The one with the highest accuracy limit is also called its maximum range, and the highest accuracy limit is called the actual limit.
The basic error of the AC digital power meter is reduced to the power frequency range of 45-65Hz5.
5.1 Basic error
In this specification, the error of the digital power meter is expressed as the reference error of the full rated power. In the technical specifications of the power meter, there are clear provisions for the allowable value of the basic error, and in the instructions for use of the power meter, its main contents are quoted: national limit, wide band, full power. The national digital meter has different accuracy requirements for different power, different power factor ranges and different limit values. If necessary, the allowable value of the basic AC error is expressed in the form of this related function.
Digital power meters should preferably use the following accuracy levels: 0.02, 0.05, 0.1, 0.2, 0.5.
The error between the basic frequency range and the basic frequency limit of the power meter in % should be equal to the following accuracy level code:
5.2-year stability and added error
In the technical specifications of digital wattmeters, there should be clear regulations corresponding to the standard level for the annual stability of the indicated value and the allowable value of the added error within the allowable range of the influence quantity, and the three main contents should be listed in the instructions for use of the wattmeter: {Insulation requirements between each circuit
Single-phase wattmeters (power converters) used to form three-phase wattmeters often have output terminals for current meters or real pulses and digital pulses. These terminals should be at ground potential during use, and they should be electrically insulated from the power supply (or transformer) circuit or current circuit. The insulation can withstand the rated voltage value within the voltage range. When the potential difference between the common end (with *) of the voltage circuit and the current circuit of the power meter (or transformer group) to the output end increases from zero to the rated voltage of the meter, the power meter indication changes to less than 12 scales of its basic error. Figure 4 shows the total circuit of the meter's true value
. Considering that the single-phase power meter is used for actual measurement of the transformer circuit as shown in Figure 4, the single-phase power meter used for actual measurement also meets the above requirements of this clause. When the output low-sensitivity and measured voltage circuit are connected at one end, the positive circuit terminal of the measured voltage should be the common end (the end without a sign), the common terminal of the current circuit (the end with a ★) and the common terminal of the voltage circuit (the end with a ★) should be consistent in position. This regulation does not limit the technical requirements of the power meter that is not related to the accuracy. The corresponding technical requirements should be specified in the technical policy of the power meter. When these technical requirements exist in industry standards or national standards, the technical conditions should comply with the provisions of the relevant standards.
Three verification conditions
8 When the power converter must be equipped with a DC digital voltmeter, the power converter should be verified together with the digital power meter as the digital half-power meter. In this way, the converter must not be replaced during use, and the allowable output difference of the DC digital voltmeter should be less than (/2 times the allowable error of the residual voltage. When the digital voltmeter is specified to be used at the end of the conversion, its output current and voltage should not exceed the limit of the measured value during the verification. The error is about 1 times. In use, the measurement error of the auxiliary voltage is not greater than 1/4 times the allowable error of the measured voltage.
9Digital power meters with different accuracy levels, the six error calibration parts are shown in Table 1. When the digital power meter has zero harmonics, voltage balance, current balance or white break, it should be calibrated after two calibrations according to its technical conditions! The manual power meter must strictly inspect the standard equipment and implement the calibration plan. The reference of the measured power meter is the most important thing to do. Three-village voltage, electricity and current materials are not installed for a period of time. The old machine should be of poor quality. The current has a burning potential ticket. The axis has a low increase in potential. The output of the electric quantity is limited and positioned. The upper and lower positions are prohibited. The position indicates the change of some medical reasons. There is still a state for the flat position. The single position is correct for the electric position. When the user requires it, this condition can be set. % The light allows the high position to not break the set value ± 2%,
+ (0.05lcs+lc.01)
10When setting, the relative humidity difference between the indicated value and the test value should be negligible (not more than 1/4 times of this allowable error),
11When verifying: the relative humidity of the environment of the meter under test should vary within the range of 55121%; and the ambient temperature of the meter under test should be 20℃, and the calibration is allowed at 237℃ for special requirements of model users. The allowable deviation of environmental humidity is 1℃ for 0.02-level meters, 2℃ for 0.5%, 0.1% and 0.2% for 0.5-level meters, and 15℃ for 0.5-level meters. The technical indicators of the power supply are as follows: 743
12.1 The output energy is the efficiency of the energy consumed by the system under the rated voltage and rated current.
12.2 The maximum relative value of the power supply within three minutes shall not be greater than 1/4 times the basic allowable setting value of the 12-level meter, and shall not be greater than 1/2 times the basic allowable setting value of the 5-level meter. 12.3 The setting difference of the power supply shall not be greater than 2%. The relative change of frequency within one minute shall not be greater than 10.02. 12.4 The power supply voltage or current waveform error is less than 0.5%, which is only used to calibrate the power supply voltage or current waveform error of digital power meters below level 7.1. 11.5 The phase difference between the power supply voltage and the current can be adjusted between the two ranges, and the ratio should not be less than 0.0. 12.6 The phase difference between the power supply voltage and the current should be able to be adjusted to the voltage and current with the same cut-off ratio, and the ratio adjustment accuracy should not be greater than 1% of the allowable error of the corresponding indication of the tested equipment. 12. In addition, the current loop of the battery and the positive and negative loops of the power supply should be electrically insulated to ensure that the current and voltage circuits can be connected arbitrarily. 12.B The amplitude asymmetry of the three-phase voltage should not exceed 1%. In the three-phase flash line system, the amplitude asymmetry of the three-phase voltage should not exceed [%
. The amplitude asymmetry of the three-phase current should not exceed 1%. The following formula is used to express the asymmetry of voltage or data value: asymmetry =
where x, and tt are the amplitudes of phase current and phase voltage or line voltage. 12.9 The range of the current to the corresponding voltage is not greater than 2° 13 The grid voltage supplying the meter meets the following conditions: 50+2Hz
220-10
14 Before verifying the basic error: preheat the equipment as much as possible to make the water reach a certain level. 15 Verification frequency of digital power adjustment
15,1 digital power meter can be verified at any frequency within 45-651[z. According to user requirements, it can be verified at the frequency specified by the user. (2)
15.2 In order to determine the frequency response of the meter, for the extended frequency range, the test is carried out at the upper limit frequency of its frequency range according to the specified
result. In order to determine the frequency response of the meter, in addition to the test at the upper limit frequency, if necessary, the test should be carried out at a frequency that is times the upper limit frequency. 15.3 When testing the basic error of the meter, the frequency measurement error should not be greater than ±2%. For the digital power meter with a power factor range of 0.5--1, the test should be carried out under both the conditions of =1 and .5 inductive and narrow.
For low power factor or The digital power meter of the full power factor is actually tested at 0 and the upper value of the power range (including inductive and capacitive conditions). According to user requirements, it can be tested at the specified average value. During the test, the error of the power factor is greater than ±(0.05c08|-U.01)724
17 When testing the error of the digital power meter, the connection should be as consistent as possible with the actual connection state of the workpiece: that is, it should be ensured that:
17.1 The potential between the common terminals of the seven-voltage circuit is zero, and the maximum allowable value of the potential difference is +12V
17.2 If only The power meter (or power converter) has an input terminal. In the case of single-phase, the low-end is at the same potential as the non-common terminal (small band) of the power meter. In the case of three-phase, the potential is the same as the midpoint or line of the three-phase. The deviation of 12V is allowed for the equivalent period. For standard digital power meters that are only rated for 12V, the connection can be made without following the above provisions. The calibration can be carried out under the actual connection during use.
4. Calibration Items
18. The periodic calibration of digital power meters includes the following contents: 18.1. At the frequency specified in Article 15, the power factor value specified in Article 16 and the connection state specified in Article 17, the limit values ​​of each quantity of the meter are 18.2.1 The verification of the basic error of the basic measurement limit of the digital power meter (or converter) under the inductive rated power value should be carried out at any frequency (or user-specified frequency) between 45 and 6 hours. The verification indications should be no less than 15. These indications are achieved by changing the current indication method under the rated voltage and inductive rated power value of the limit. Each indication should be equidistant, including the full-scale indication. 18.2.2 The capacitive rated power value of the basic measurement limit of the digital power meter (or converter), the capacitive and inductive error is 4-0 (or 0.089-0.5), the bottom should be within 18.2.1. The same power, rated voltage and rated current are tested.
19.2.3 For multiple digital power meters (or converters), it is allowed to calibrate the error within the specified range according to the actual use needs. After passing the partial verification, it is allowed to be used in power meters (or converters) and within the qualified range.
The power meters (or converters) tested in the partial verification should have special regulations for limited use. Digital power meters (or transformers) used at a specified frequency can be calibrated at the operating frequency: 18.1.4 Current non-basic limit only and voltage basic limit only in conjunction with the calibration. Voltage non-basic limit only and current basic limit in conjunction with the calibration. According to user requirements, the calibration can be carried out under certain specified combinations of voltage limit and current limit. The basic error of all meters and even the limit can only be calibrated under the rated voltage limit and rated current limit. The calibration frequency is the same as that of Articles 18.2.1 to 18.2.2, and the power factor value is the rated power factor and the user-specified power factor (including both running and speed conditions). 18.2.5 When the connection is not made according to the requirements of Article 17, the corresponding false error test shall be carried out, and the test results shall be corrected with the voltage test results.
19 New production and after connection The following contents shall be added to the initial calibration of the effective digital wattmeter in accordance with the provisions of clause 18.1. The withstand voltage test and the resistance measurement shall be carried out in accordance with the technical conditions. 19.2. The frequency response control contents of the digital wattmeter (or converter) are the same as those in clause 18.2. The calibration frequency is the frequency specified in clause 15.2, and the calibration shall be carried out only under the specified voltage and rated current within the measurement limit. For the digital wattmeter (or converter) with the specified frequency range, it is allowed to calibrate part of the frequency band according to the actual needs. In this way, the effective fast meter (or converter) with the specified frequency range of 745 shall only be allowed to work within the specified operating range of the calibration, and the calibration certificate shall be stamped with a special seal indicating the frequency range. 19.3. The measurement range of the potential difference between the current loop and the positive circuit terminal: 19 .41 If the digital power meter (or transformer) has an auxiliary output, the influence of the potential difference between the output and the low voltage output should be measured.
19.5 Measurement of the mutual influence between the individual power units of the three-phase power meter 19.6 According to the provisions of the technical specifications, measure the additional error coefficient of the main influencing quantity (such as auxiliary error, etc.) Five verification methods
(-) Appearance inspection
Effective appearance
20.1 The mark of the meter under inspection is that it meets the provisions of Article 3 of this standard. If it does not meet the provisions, it will not be calibrated. 20.2 When the power is not turned on, check whether the power meter under inspection and its components have defects that affect the accuracy of the output. When such defects exist, it will not be calibrated.
20.3 Check whether the digital power meter is working normally. If there is any damage that affects the positive and negative working ratio (such as short circuit) 20.4 The digital power meter that fails to meet the standard shall not be tested with the test results. (II) Method for testing basic errors of single-phase digital power meter 21 Single-phase digital power meter [or converter], under the conditions of Table 1 (see 9), the basic error shall be tested according to the items specified in Clause 18.2.
This procedure recommends that the standard power source method and comparison method be used to test the meter under test. 22 Use the standard power source method to test the single-phase digital power meter. 22.1 The standard power source shall meet the various requirements for the power source listed in Article 12. Its measurement limit and frequency range shall include the test limit and frequency range of the meter.
After the standard power source is continuously tested, the output power of the meter can still be correct. The standard power source is within the range of the meter calibration resolution, and should hold a certificate of qualification within the calibration period. The error of its output power indication should not be more than 1/4 times the allowable error of the corresponding indication of the meter being tested. It is allowed to calibrate the meter with a standard power source whose output indication error is not more than 1 times the allowable error of the corresponding indication of the meter being tested, but at this time, the indication of the standard power source should not be more than 14 times the allowable error of the corresponding indication of the meter being tested, and the indication P should be used. The data in the calibration certificate within the calibration period should be corrected. 22.2 The connection of the single-phase digital power meter with a standard power source is shown in Figure 5. The allowable calibration error of the line connection should be small enough to be ignored, and should not be more than 1 times the allowable error of the corresponding indication of the meter being tested. The following requirements should be met: 22.2.1 The voltage circuit being tested and the circuit of the same name should be connected together. 22.2.2 If the meter under test (power transformer) is connected to the auxiliary output terminal, the low end of the output terminal is connected to the non-isotropic voltage of the power under test.
22.2.3 The power source is directly connected to the shell of the test meter (or transformer and DC digital voltmeter), and connected to the ground potential. The ground potential should generally be connected to the non-isotropic voltage of the power under test. It is allowed to connect the ground potential to the non-isotropic voltage of the power under test, but at this time, the meter under test (or transformer) and the DC digital voltmeter should not be connected in this way, and the error caused by the transformer connection should be less than 18% of the allowable error of the test meter. 2.2.4 The voltage and current of the power circuit under test should be minimized as much as possible, and the connection between the two circuits should be minimized as much as possible. - Generally, the method is adopted to achieve 2.2.4.1 The two circuits are connected in reverse, or the circuits are connected as close together as possible. 2.2.4.2 The two circuits are as far away from each other as possible. 2.2.5 The leakage current between the line and the circuit of the current loop can be ignored. If necessary, the leakage current can be reduced by using shielding protection measures such as equal current components.
2.2. The influence of the voltage drop in the voltage circuit should be small enough to be negligible. 22.3 The error of the measured value can be expressed by the following formula: A=PP
Where P is the measured value:
P,—the minimum value of the standard power source.
22.4 When calibrating an AC power converter, take the following formula: Px=RmLi.
For the frequency conversion system of the converter, use a direct current digital voltmeter to measure the output voltage of the converter, and the value of the direct current digital voltmeter shall comply with the requirements of this regulation.
When the rated voltage of the converter is P, and the rated voltage of the self-contained output voltage is greater than 23°, the value of K can be calculated using the following formula:
Kn-P:/U
23.1 When calibrating a single-phase digital power meter by comparison, the expected power limit and power factor range shall include the power range and power factor range of the digital power meter being tested. The power range and power factor of the standard power meter to be calibrated shall have a calibration certificate that is valid within a specified period of time.
The allowable error of the indication of the standard rate meter should be less than 1A times the allowable error of the corresponding indication of the meter under test. The standard power meter is allowed to be used for verification, but the error is less than 12% of the indicated value. The error must be less than 12% of the indicated value. The indicated value must be corrected with the data from the verification, and the annual instability of the standard power meter must be no greater than the basic error allowed by the standard power meter. The voltage drop and current circuits of the standard power meter should be electrically independent, so that these circuits can be connected within any range of electrical connections. The standard power meter is allowed to use voltage sensors or current transformers to achieve the protection of the extended voltage or current limit or the mains voltage. The voltage transformer and current transformer error should only be less than 1/10 of the allowable error of the standard power meter. 23.2 The current transformer used for verification shall comply with the requirements of Article 12. 23.3 The circuit of the single-phase power meter shall be used for comparison verification, as shown in Figure 6. The standard wattmeter and single-phase AC power supply are connected as follows to form an equivalent standard watt source: the standard wattmeter's current loop should be connected to the non-public end of the photoelectric measurement output terminal, and the equivalent standard wattmeter's current loop should be connected to the non-public end of the photoelectric measurement output terminal. The indication of the equivalent standard wattmeter formed in this way is the indication P of the standard wattmeter. If the sign of the standard P needs to be changed, the current loop of the standard power meter can be swapped. Then, the standard power meter has:
(indication value
before inspection
kind of power meter
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Figure 6 Strategic connection plan of the comparison power meter 23.4 The error limit of the inspected indication value P obtained by comparison inspection can be expressed by the following formula: aP, =H,- P,=P, ±P:
The drum inspection value is P, but the positive and negative signs of the standard are determined by formula (6) (take the positive sign) and formula (7) (take the negative sign).
When the meter under test is a transformer, the formula (8) will be expressed by the formula (4). The content of formula (4) can be found in 22.4.
24When the test meter does not have the necessary parts for overall verification and does not meet the requirements of 2.1 of Appendix 2, it is allowed to use the component verification method of Appendix 2 to verify the single-phase digital power meter (or transformer). The standard setting method for single-phase digital power meter shall be reviewed and approved by the technical management department of the unit carrying out the verification.
(III) Setting method for basic error of three-phase equal power meter 25 The verification method for basic error of one-phase equal power meter shall be carried out according to the provisions of 16.2 in Table 1. This procedure recommends the standard power limit method and the comparison method of two three-phase power meter verification methods.
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