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Leakage Current Measuring Instrument (Table) Verification Regulation JJG: 843—1993
Leakage Current Measuring Instrument [Table]
Verification Regulation
Yerificaion Regulation
Leakage Current Measuring Instrument
ad Meter
JJGB43—1993
Verification regulations are approved by the National Supervision Bureau on July 1, 2016, and implemented in January 1994. Responsible unit: Henan Technical Preparation Bureau
Reform unit: Henan Testing Institute, China University of Measurement and Control
The technical department of the regulations is responsible for the interpretation of the regulations. The main drafters of this regulation are:
Chen Haitao
Wang Luyuan
Chen Chuanxian
(Henan Metrology and Testing Institute
(China University of Measurement and Control)
(Henan Metrology and Testing Institute)
Participants:
Du Waguo
Tuyi
(National Electric Power Quality Supervision and Inspection Center)
(Provincial Instrument Testing Institute)
(China University of Computer Science and Technology)
Overview·
Technical requirements·
Construction conditions..
(I) Calibration environment conditions
(I) General requirements for calibration equipment
IV. Calibration items
V. Calibration methods
(I) Appearance and normal working state inspection
(I) Verification of instrument error
(I) Determination of input circuit error
(IV) Test itemsbzxZ.net
Handling of calibration results and calibration period·Appendix
Appendix 1 Verification record format
Appendix 2 Frequency characteristics of the impedance of the medical instrument under test·Record
: 802
Verification procedures for leakage current measuring instruments [meters] This procedure is for the verification of the leakage current measuring instruments (meters) during use and after inspection. The comprehensive test device measures the full reflow test part of the comprehensive test rate card. This procedure is not applicable to the detection of the leakage current measurement of the components and the slip protection device. Overview
Leakage current measuring instrument (meter) (hereinafter referred to as the instrument under test) is used to measure the leakage current that is not related to work and is generated by the working power supply (or other power supply) of the electrical appliance through the insulation or distributed impedance. The input positive impedance is reported according to the impedance of the reporting position. The meter is mainly composed of positive impedance conversion, range conversion, AC/DC conversion, amplification, indication and cutting, etc. Some also have overcurrent protection, sound and light lightning alarm circuit voltage adjustment device, and its indicator is The display device is divided into two types: template type and digital type. Technical requirements
1 Measurement range
1.1 The leakage current measurement range is 0~20m/
1.2 Different range settings are allowed:
2.1 Under the premise of disconnecting the capacitor simulating human body characteristics connected in parallel with the input circuit of the instrument under test, the error or relative error is given according to whether the instrument under test is analog or digital. Under the premise of connecting the power, the accuracy is given:
2.2 The maximum allowable error of the instrument under test should be ±5% (when the power is disconnected in 2.1, it should be ±6% at 50Hz). When determining whether the error of the instrument is appropriate, the corresponding technical conditions or instructions can be used as the basis for the current setting:
3. The error should be consistent with the error of the instrument under test. Different measuring ranges have different resolutions, 4 frequency range
41. The meter under test is 20H-5Hz: the long-term test instrument is 201z-1kllz, its high rate response of 1kH should be inversely proportional to the response, the impedance maximum frequency characteristic is gradually recorded as required, 1.2 The meter under test can also have DC or LC+AC measurement function. 5 Input resistance
5.1 For general instruments under test, it is 1750±250, and for effective instruments under test, it is 100±1UH.5.2 For instruments under test, in order to adapt to different international standards, there are different input resistances when inputting into the circuit: for general instruments under test, it is 225+15us, and for effective instruments under test, it is 150+110ug. Insulation limit: not less than 7M2,
8 Leakage current: at LX50Hz, according to the certificate, the instrument under test is general or monthly, and 1.10 times or 1.10 times the rated voltage of the test device (not less than 220V) is applied), the leakage current of the casing is not more than 0.2mA.9 Dielectric strength: When the AC power supply is in the non-working state, the power switch is in the on position, and the voltage between the power supply and the casing is 50H. The actual sine wave voltage of 1.kV lasts for 1min, and there should be no k-drive and breakdown. 800
（-）Calibration environmental conditions
10 The calibration environmental conditions shall meet the following requirements
10.1 Environment: to ±5t;
10.2 Relative humidity: (60±15)%:
10.3 Battery: 22011V:
10.4 Power supply frequency: 5l:=0.51x;
Three certain conditions
10.5 Total distortion coefficient of power supply voltage: not more than 5: (a) Control equipment and its academic
11 Calibration equipment The error calibration method adopted is different in different currencies. The main equipment for verification are: 11.1 AC standard current source:
11.2 AC direct current digital voltmeter, digital ammeter or mathematical multimeter: L1.3 AC standard resistor and AC standard resistor box: 1.4 Digital frequency meter:
L1.5 Insulation tester or megameter, leakage current measurement: positive pressure tester, etc. The total uncertainty of each verification equipment shall not be greater than [/3] of the allowable error of the instrument under test. 12.1 The actual error of the AC standard current source within the frequency range of 20H~5kHz shall be 1/5 of the calculated error of the controlled instrument, and its input voltage shall be sufficiently high; the resolution and stability within minutes shall be the same. The error caused by the control instrument shall not exceed 1/3 of the allowable error of the control instrument. 1/10 of the allowable error, the total peak cumulative effect of the wave tower is better than 0.5% for the semi-mean value end of the test instrument; for the effective value end of the plate grid instrument, it should be better than 5%. 12.2. The actual error of the DC standard current source, the output voltage, the resolution and the error caused by the stability within half a minute are the same as those in Clause 12.1, and the error caused by the noise should be less than 1/5 of the allowable error of the instrument under test. 12.3 The actual error of the standard AC and DC digital ammeter and the digital ammeter in the frequency range of DC or 20H-5lHz shall not exceed 1/10 of the allowable error of the instrument under test. 12.4. The error caused by the stability of the AC and DC voltage regulator within half a minute and the adjustment requirement shall not exceed 1/10 of the error of the instrument to be controlled. The difference between the effective wave and the noise of the DC power supply should not exceed 1/5 of the allowable error of the instrument under test. The AC power supply should have a frequency range of 20Hz to 5kFz and the frequency should be adjustable. The total waveform true coefficient should meet the requirements of 12.1.
12.5 The non-inductive standard resistor or AC standard positive box should be able to withstand at least 20mA. Its resistance value is about 10.-1(0, the resistance value recognition should not exceed 1/10 of the allowable error of the meter being tested, and the time constant should be less than 1×10-g12.% The measurement range of the digital frequency meter is 5H~10VHz, and the frequency measurement error should be better than 1×10312.7 The error of the leakage current of the entire device should not exceed 1/10 of the allowable error of the meter being tested. 12.8 The insulation resistance, leakage current and dielectric strength of the equipment used should meet the requirements of the relevant standards: 13 Under the premise of meeting the above requirements, it is allowed to cross the comprehensive efficiency multiplication or the calibration device composed of the corresponding calibration equipment: Under the premise of ensuring that the total uncertainty of the calibration device meets the requirements, it is allowed to use other methods of medical error distribution to perform calibration, four calibration items 14.1 The items of periodic inspection shall include: appearance and performance inspection, instrument error inspection, input resistance and input 80° circuit time constant. 14.2 In addition to the items of periodic inspection, the newly manufactured instrument shall also have insulation resistance, terminal resistance and electric force resistance tests. The instrument under inspection shall also have the test of the access board and characteristics. 14.3 The instrument under inspection after static treatment shall have the additional inspection items added according to the repair department. 14.4 For the smooth current display instrument with test chamber voltage or test voltage filter device, the corresponding test voltage detection loop shall be added. 14.5 For the meter under test with leakage current alarm, the preset error of leakage current shall be measured. V. Verification method
(I) Check the current and working condition
15 The meter shall have necessary signs to ensure correct use, and shall not have defects that may cause measurement errors and affect the overall performance. 16 The meter shall be grounded, preheated, and the analog indicator shall be able to inquire about zero correctly, and the needle shall not be stuck: the digital indicator shall be able to display normally, and the display position shall not be less than 3 digits. The corresponding control indicator lights shall be able to light up, and the sound, light and overcurrent protection functions shall be able to function properly.
(II) Verification of the meter reading error
17 Selection of verification points
17.1 For the meter under test with both DC and AC functions, the verification shall be carried out under DC and AC conditions respectively.
17.2 For the measurement function of the alternating current, it should be calibrated in reverse under 50H and the specified standard. 17.3 When the frequency is 50H, select the 2m! of the maximum resistance as the full calibration range. You can also select a certain range as the full calibration range according to the user requirements, and the remaining range is the non-full calibration range. 17.4 The calibration points of the full calibration range shall not be less than 5 points, including the upper limit of the range and evenly distributed. For the calibration of the non-full calibration range, for analog indication, at least the middle digital range and 1 limit should be calibrated; for digital half-indicator, at least the upper limit should be calibrated; for the calibration of the 20m4 range, it should be calibrated to at least 10 points. 17.5 For the calibrated meter with the same input resistance, it should be calibrated without the whole resistance. 18 For the calibration of the instrument error, the standard current source method can be used for the standard digital meter. 19 Standard current source method
19.1 The calibration principle of the standard current source method is shown in the figure.
Sensitive air quality
Figure! The calibration method using the standard current source method
The calibration method should be different depending on the instrument under test (one end of the instrument under test is grounded or connected to the external charge, metal: the internal circuit is connected to the screen, the internal circuit is not grounded, and its shield is connected to the low-voltage: light shielding and metal shell, etc.). 19.2 According to the measurement function of the instrument under test (TX or AC), select the output (DC or AC) of the standard current source. Adjust the standard current source input to make the instrument under test reach the set point, and take the set value of the standard current source as the actual value. 19.3 Depending on whether the instrument under test is analog or digital, calculate the reference error according to formula (1) or the error according to formula (2). Reference error of the instrument under test: Batch error of the instrument under test: Display value of the instrument under test:
Set value compiled by the standard source:
Upper limit of the corresponding range of the instrument under test,
20 Standard measuring instrument method
1-10×10 0%
20.1 The calibration principle of the standard digital voltmeter method is shown in Figure 2. 21.1 When the output current accuracy of the adjustable current source cannot meet the calibration requirements of the standard current source method, the method shown in Figure 2 (a) can be used to read the actual value of the output current with a standard digital voltmeter.
20.3 Since the standard current source method requires the current source to have a sufficiently high output voltage, it is difficult to select a power source. The method shown in Figure 2 (6) can be used to use an adjustable voltage meter to supply the output current. 21.4 (c) is to use a standard digital voltmeter to measure the voltage drop on a known resistor, and calculate the actual current according to formula (3). Formula
Standard digital voltmeter indication:
The actual value of the non-inductive standard resistor is preferably in the range of 10 to 1000.
20.5 The error of the meter under test is still calculated according to formula (1) or formula (2), but in the formula 2 (a), 2 () are the indications of the standard digital ammeter, and for Figure 2 (), it is the calculated value of formula (3).
(III) Determination of input resistance
2 Determination of input resistance
21.1 The original circuit for input resistance measurement is shown in Figure 3. 21.2 The analog capacitance of the meter under test is connected to the circuit of the meter under test. When measuring the input resistance under DC state, any input resistance block of the meter under test can be selected, and the adjustable power supply can be adjusted to make the output resistance close to the upper range of 2mA. Read the readings of the digital voltmeter and the digital ammeter respectively, and calculate the input resistance of the corresponding output block of the instrument according to formula (4).
Input equipment group of the instrument under test;
Cable power supply
Salt, positive electrical appliance
Teaching standard most sub
Electric soul meter
Standard most
Electricity meter
Standard most digital
Electricity is not measured
Laser plate
Takeshi Institute
Be collected Figure 2 shows the error of the digital meter (a) standard digital meter and the stable current meter: () standard digital meter and the standard digital meter for the five-season electricity network: () standard digital meter for the five-season electricity network: ... When there are multiple input resistances under test, please select the input resistances of the same type. Calculate the input resistance of the cabinet according to 21.2.
21.4 When the instrument can disconnect the capacitors of the same type or parallel connection, you can also refer to 21.2 and 21.3 to measure the input resistance under AC state. At this time, the above capacitors: the frequency is selected as 50H, and the input resistance is calculated by formula (4), but U and "are both effective values. 22 Input circuit time measurement 22.1 Connect the input circuit of the instrument under test in parallel with the human body characteristics, and measure the input circuit time constant as shown in Figure 4.
Digital electric meter
Charge the time constant of the input circuit.
Figure 4 Circuit time constant measurement
Provide risk only
22.2 Set the meter to AC, 2mA and input resistance range, select a certain 1. Adjust the adjustable stable power supply to increase the current to the upper limit of the range, read the indications of the digital rate meter, digital ammeter and digital three-meter meter, and calculate the effective time of the tumor by formula (5):
Input circuit voltage value:
at -1 digital frequency indication value (for the convenience of calculation, the adjustable stable power supply frequency can be selected as 159, 21lz or 1592Hz?;
- Select the input resistance value of the resistance range: 1 - Digital ammeter value (with Effective value: Digital electrical value (effective value) [IV] Other items to be checked 23 Determination of insulation resistance 1. The instrument is in non-operating state, the switch is set to the appropriate position, and a 50CV test voltage is applied from the power input end to the housing. After stabilization for 5s, the insulation resistance value is measured. 24 Determination of leakage current 24.1 The leakage current should be measured after the insulation is determined to avoid 24.2 The meter to be tested shall be placed on an insulating workbench and operated at a rated voltage of 1.0F or 1.1F after being separated from the transformer until the temperature reaches the normal level. 24.3 The leakage current measuring instrument (meter) shall be used to adjust the current values of the line and neutral line to the shell or to the ground through the conversion switch and the larger value as the measurement result: 25 Dielectric strength test
for AC core The temperature test of the instrument under test shall be carried out according to the requirements of 9. During the test, the test voltage shall be gradually increased to a certain level to avoid obvious transient changes: the medium voltage shall be kept at 1m.1 and then steadily decreased to 4m.26 Test voltage verification 2.1 For the instrument under test composed of a transformer with adjustable output voltage or an isolation transformer with fixed output voltage and an adjustable output voltage, the test voltage shall be controlled in pairs. 26.2 The original circuit of test voltage determination is shown in Figure 5. 26.3 Test the error of the voltage indicator, according to the digital form of the indicator, calculate the error of the voltage indicator according to the formula (6) or (7): Um
Blue Ux100%
Wherein--test the error of the voltage indicator:
-test voltage indicator indication value;
J.--digital voltage indication value:
1.-test the error of the voltage indicator, 4 test the voltage return according to the smoothness, (6)
voltage 5 test the principle of the circuit
original: 1, [the degree of the transmission of the instrument: the actual research table
26.5 The total true coefficient of the waveform of the cross-sparse test voltage, the test from the five 220V time straightness measuring instrument direct measurement, 27 test impedance frequency characteristic inspection
27.1 Check the input characteristics of the environment such as the standard method
The meter
The meter
The ground plate
The impedance gradient characteristic of the meter is shown in Figure 6.
In the figure, the meter is 5I-1MIz
The actual reading difference is 11% of the square element resistance, and the value is 10~100. The frequency range of the transmitter is 16Hz-2MHz, the amplitude is 0~20V, and the total accuracy is +3%.
Z7.2 When the current of the instrument under test is 20mA or less, adjust the output amplitude of the signal generator to keep the voltage at the positive value of the meter A. (For example, 1 mV, change the frequency of the signal generator to 10Hz, J0Hz, kHz, k!x, 1JeHz, 5KkH and 1AMHz respectively (use the effective frequency optical reading, take the value of the electric voltmeter B to form 27.3 based on the internal impedance of the instrument under test 1000Q/0.15F), calculate the theoretical value L of the meter under test at a given periodic rate.
27.4 Calculate the old value according to the periodic mountain (8) and change it to the theoretical frequency The degree of continuity is consistent with the rent. nUx100%
Formula 7—-Input frequency characteristic error: ... electronic value;
theoretical value of the instrument's response:
the sound of the flexible ability
For the digital type, you should only check its display ability and check whether each bit can be transmitted according to the reverse change of its end code. You can check it bit by bit according to the effective code shown in the figure. You can check it according to the reverse number of the related bit type shown in the figure. The instrument can be checked without any lag. In addition, it is required that there is no interruption in the digital display, the unit is always refreshed, and the whole unit is displayed. The meter is tested in digital mode. Combined with the calibration of the meter, the resolution of the meter is measured. When the measured value is low, the reading is from a standard current source, a stable power supply or an adjustable insulator, so that the instrument changes by one position near the range limit, and reads the standard current and standard digital voltage respectively. The corresponding small debt of the meter or mathematical ammeter is obtained, and the corresponding actual value of the seven sparse is calculated according to formula (9) 110
Where A-the meter under test:
-the actual current before the meter under test changes one character: I
-the actual current after the meter under test changes one character. 3. The inspection of the special items of the meter to be inspected shall refer to the corresponding product label or manual for retrograde inspection. VI. Processing of verification results and verification cycle
31 The number of the calibration record should be calculated first and then rounded. The rounding should follow the four-in-one and adjustment rules. The last digit should be consistent with the resolution of the instrument under test. The rounding error of the instrument error should not exceed 10% of the allowable error of the instrument under test. The rounding error of the output resistance should not be greater than [02]. The rounding error of the time band number should not be too large. The calibration station will process the result of the rounding. Determine whether the instrument under test meets the corresponding technical indicators. , after the verification is qualified, a verification certificate will be issued; if the verification fails, a verification result notification will be issued. The verification certificate only gives a brief summary of the qualified results, without giving specific data; the verification result notification will indicate the items that do not meet the requirements. 33. The verification cycle of the instrument under inspection shall not exceed "years". It can be determined by the user and the general verification plan in advance according to the regulations. Attached is the appendix! The format of the verification certificate is the verification unit. |Niu Mian Kang
Standard Preparation
Model
Setting Selection
Maintenance Welcome
Furnace Source Electricity
Verification Must Ratio
Micro-aggregation
External Secret Correction Work Check
2 Instrument Error
Confirmation
Verification Summary
According to the Verification Period
Actual Setting (nA)
3 Input Month R-
Input Grid 4 Input circuit time with digital input current: insulation resistance: leakage current: impedance measurement: digital current meter digital current meter indication value digital current meter digital current meter Appendix 2 Impedance frequency characteristics of medical meter for measuring impedance using national impedance meter terminal resistance measurement time
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