【JJG 314-2010】5.1.3 Standards
Standards include standard voltage transformers, power frequency voltage ratio standards and capacitive voltage ratio devices.
The accuracy level and technical performance of the standards shall meet the following requirements:
5.1.3.1 The rated voltage ratio of the standard is the same as that of the voltage transformer under test, the accuracy is at least two levels higher than that of the voltage transformer under test, and its actual error is not greater than 1/5 of the error limit of the voltage transformer under test.
When the standard does not meet the above conditions, a standard with one accuracy level higher than the voltage transformer under test can be selected and corrected according to the formula in 5.4.3.2.
【Article Interpretation】The requirements for the standard in JJG313-2010 and JJG314-2010 regulations are that the transformation ratio is the same as that of the transformer under test, the accuracy is at least two levels higher than that of the transformer under test, and the actual error is not greater than 1/5 of the error limit of the transformer under test.
It is also allowed to use a higher level standard and then correct the error introduced by the standard.
This part is the same as the requirements of the obsolete JIG313-1994 and JJG 314-1994 regulations.
At present, the first choice for 0.05-0.01 current standards is current transformer, the first choice for 0.005 and 0.002 current standards is double-stage current transformer, and the first choice for 0.001-0.0002 current standards is compensated current comparator.
The first choice for 0.05-0.01 voltage standards is voltage transformer, the first choice for 0.005 and 0.001 voltage standards is double-stage voltage transformer or capacitive voltage ratio standard, and the first choice for 0.0005 and 0.0002 voltage standards is inductive voltage divider.
The power frequency voltage ratio standard value is derived by the addition circuit of the inductive voltage divider and the series voltage transformer, with the highest voltage reaching 1000kV.
The overall level of current and voltage standard devices has reached the world's first-class level, providing a reliable technical guarantee for the implementation of JJG313-2010 and JIG 314-2010 metrological verification procedures in my country.
To understand the metrological technology for the derivation of power frequency current and voltage values in my country, please refer to the national metrological verification specifications JIF 1067-2014 "Calibration Specifications for Power Frequency Voltage Ratio Standard Devices" and JIF 1068-2000 "Calibration Specifications for Power Frequency Current Ratio Standard Devices".
【JJG313-2010】5.1.3.2 The rise and fall variation of the standard device shall not exceed 1/5 of the error limit of the standard device.
【JJG314-2010】5.1.3.2 The rise and fall variation of the standard device shall not exceed 1/5 of the error limit of the standard device.
[Article Interpretation] The standard current and voltage transformers in the standard instrument are current and voltage transformers for measurement.
The requirements for their rise and fall variation have been clearly stipulated in 3.2 that they shall not be greater than 1/5 of their error limit.
The rise and fall variation of the power frequency current ratio standard instrument, power frequency voltage ratio standard instrument and capacitive voltage ratio device shall also not be greater than 1/5 of their error limit.
【JJG313-2010】5.1.3.3 During the calibration period, the error change of the standard instrument shall not be greater than 1/3 of its error limit.
【JJG314-2010】5.1.3.3 During the calibration period, the error change of the standard instrument shall not be greater than 1/3 of its error limit.
[Article Interpretation] According to the provisions of 3.3, the error change of the standard current and voltage transformer during the calibration period shall not be greater than 1/13 of its error limit.
The error change of the power frequency current ratio standard instrument, power frequency voltage ratio standard instrument and capacitive voltage ratio device during the calibration period shall also not be greater than 1/3 of its error limit.
【JJG313-2010】5.1.3.4 The standard must have a valid verification or calibration certificate.
When the standard is two accuracy levels higher than the current transformer being tested, its actual secondary load should not exceed the rated and lower limit load range.
When the standard is one accuracy level higher than the current transformer being tested, the difference between the actual value of the secondary load during use and the load marked on the certificate should not exceed 10%.
The differential current loop load should be included in the actual secondary load.
The influence of the differential current loop voltage drop of the two-stage current transformer and the compensated current comparator on the measurement result should not be greater than 1/10 of the error limit of the current transformer being tested.
