This Part of GB/T 16927 is applicable to complete measuring systems, and to their components, used for the measurement of high voltages during laboratory and factory tests with direct voltage, alternating voltage and lightning and switching impulse voltages as specified in GB/T 16927.1. For measurements during on-site tests see GB/T 16927.3.
The limits on uncertainties of measurements stated in this Part apply to test levels stated in GB 311.1. The principles of this Part apply also to higher levels but the uncertainty may be greater.
This Part includes:
a) Defines the terms used;
b) Describes methods to estimate the uncertainties of high-voltage measurements;
c) States the requirements which the measuring systems shall meet;
d) Describes the methods for approving a measuring system and checking its components;
e) Describes the procedures by which the user shall show that a measuring system meets the requirements of this Part, including the limits set for the uncertainty of measurement.
Foreword V
1 Scope
2 Normative References
3 Terms and Definitions
3.1 Measuring systems
3.2 Components of a measuring system
3.3 Scale factors
3.4 Rated values
3.5 Definitions related to dynamic behaviour
3.6 Definitions related to uncertainty
3.7 Definitions related to tests on measuring systems
4 Procedures for Qualification and Use of Measuring Systems
4.1 General principles
4.2 Schedule of performance tests
4.3 Schedule of performance checks
4.4 Requirements for the record of performance
4.5 Operating conditions
4.6 Uncertainty
5 Tests and Test Requirements for an Approved Measuring System and Its Components
5.1 General requirements
5.2 Calibration — Determination of the scale factor
5.3 Linearity test
5.4 Dynamic behaviour
5.5 Short-term stability
5.7 Ambient temperature effect
5.8 Proximity effect
5.9 Software effect
5.10 Uncertainty calculation of the scale factor
5.11 Uncertainty calculation of time parameter measurement (impulse voltages only)
5.12 Interference test (transmission system and instrument for impulse voltage measurements)
5.13 Withstand tests of converting device
6 Measurement of Direct Voltage
6.1 Requirements for an approved measuring system
6.2 Tests on an approved measuring system
6.3 Performance check
6.4 Measurement of ripple amplitude
7 Measurement of Alternating Voltage
7.1 Requirements for an approved measuring system
7.2 Tests on an approved measuring system
7.3 Dynamic behaviour test
7.4 Performance check
8 Measurement of Lightning Impulse Voltage
8.1 Requirements for an approved measuring system
8.2 Tests on an approved measuring system
8.3 Performance test on measuring systems
8.4 Dynamic behaviour test
8.5 Performance check
9 Measurement of Switching Impulse Voltage
9.1 Requirements for an approved measuring system
9.2 Tests on an approved measuring system
9.3 Performance test on measuring systems
9.4 Dynamic behaviour test by comparison
9.5 Performance check
10 Reference Measuring Systems
10.1 Requirements for reference measuring systems
10.2 Calibration of a reference measuring system
10.3 Interval between successive calibrations of reference measuring systems
10.4 Use of reference measuring systems
Appendix A (Informative) Uncertainty of Measurement
A.1 General
A.2 Additional definitions
A.3 Model function
A.4 Type A evaluation of standard uncertainty
A.5 Type B evaluation of standard uncertainty
A.6 Combined standard uncertainty
A.7 Expanded uncertainty
A.8 Effective degrees of freedom
A.9 Uncertainty budget
A.10 Statement of the measurement result
Appendix B (Informative) Examples for the Calculation of Measuring Uncertainties in High-voltage Measurements
B.1 Example 1: Scale factor of an AC measuring system (comparison method)
B.2 Example 2: Scale factor of an impulse voltage measuring system (component method)
B.3 Example 3: Front time of lightning impulse voltages
Appendix C (Informative) Step Response Measurements
C.1 General
C.2 Additional definitions
C.3 Circuit for step response measurements
C.4 Requirements for the step response of a component
Appendix D (Informative) Convolution Method for the Determination of Dynamic Behaviour From Step Response Measurements
D.1 General
D.2 The convolution method
D.3 Procedure for performing the convolution calculation
D.4 Uncertainty contributions
D.5 Discussion of the calculated errors of impulse parameters
Bibliography
Figure 1 Amplitude-frequency Response with Examples for Limit Frequencies (f1, f2)
Figure 2 Calibration by Comparison Over the Full Voltage Range
Figure 3 Uncertainty Contributions of the Calibration (Example with Minimum of 5 Voltage Levels)
Figure 4 Calibration by Comparison Over a Limited Voltage Range, with an Additional Linearity Test
Figure 5 Linearity Test of the Measuring System with a Linear Device in the Extended Voltage Range
Figure 6 Shaded Area for Acceptable Normalised Amplitude-frequency Responses of Measuring Systems Intended for Single Fundamental Frequencies fnom (to be Tested in the Range (1, ..., 7) fnom)
Figure 7 Shaded Area for Acceptable Normalised Amplitude-frequency Responses of Measuring Systems Intended for Single Fundamental Frequenciesfnom2 to fnom2 (to be Tested in the Range fnom1 to 7 fnom2)
Figure A.1 Normal Probability Distribution p(x)
Figure A.2 Rectangular Probability Distribution p(x)
Figure B.1 Comparison Between the System Under Test, X, and the Reference System, N
Figure B.2 Front Time Deviation ΔT1,j of System X, Related to the Reference System N, and Their Mean ΔT1m in the Range of T1 = 0.8 μs ... 1,6 μs
Figure C.1 Definitions of Response Parameters
Figure C.2 A Unit-step Response g(t) Showing an Initial Distortion of Initial Distortion Time T0
Figure C.3 Suitable Circuits for Step Response Measurement
Table 1 Tests Required for an Approved Direct Voltage Measuring System
Table 2 Required Tests for Uncertainty Contributions in Ripple Measurement
Table 3 Tests Required for an Approved Alternating Voltage Measuring System
Table 4 Tests Required for an Approved Lightning Impulse Voltage Measuring System
Table 5 Tests Required for a Switching Impulse Voltage Measuring System
Table 6 Recommended Response Parameters for Impulse Voltage Reference Measuring Systems
Table A.1 Coverage Factor k for Effective Degrees of Freedom veff (p = 95.45 %)
Table A.2 Schematic of an Uncertainty Budget
Table B.1 Result of the Comparison Measurement
Table B.2 Summary of Results for h = 5 Voltage Levels ( VXmax = 200 kV)
Table B.3 Result of Short-term Stability Measurement
Table B.4 Uncertainty Budget of the Assigned Scale Factor FX
Table B.5 Comparison of Impulse Voltage (Positive Polarity)
Table B.6 Comparison of Impulse Voltage (Negative Polarity)
Table B.7 Summary of Results for Each Voltage Levels
Table B.8 Nonlinearity Measurement for Extended Range
Table B.9 Short-term Stability Measurement
Table B.10 Uncertainty Budget of the Assigned Scale Factor FX
Table B.11 Calibration Result for Front Time T1 and Deviations
Table B.12 Uncertainty Budget of the Front Time Deviation ΔT1cal
