The text of the International Standard IEC was approved by ISO/ IEC Guide Uncertainty of measurement -. Find the most up-to-date version of IEC at Engineering also reflected by the older editions of the relevant standard IEC For good practice in HV test fields, this Sect. on HV measurement and uncertainty .
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These limits are under consideration. The wave shape used to determine the scale factor should be within the range covered by the convolution method described in Annex D. Some guidance on determining uncertainty contributions, that need to be considered, and on their combination is given in Clause 5 and Annexes A and B. NOTE 2 Preferably one measuring system is used to measure all of the required quantities, i. Table 2 – Required tests for uncertainty contributions in ripple measurement Type of test Type test Routine test Performance test Performance check Scale factor of measuring system at the calibration 5.
If Vgff is not an integer 60600-2 or truncate Vgff to the next lower integer.
Full text of “IS/IEC High – Voltage Test Techniques, Part 2: Measuring Systems”
Scale factor of an AC measuring system comparison method An AC measuring system of rated voltage kV, denoted by X, is calibrated by an accredited calibration laboratory in the test laboratory of the customer. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. It describes how the output estimate y is influenced by small variations of the input estimate X.
To obtain the measuring uncertainty of the approved measuring system, those of the components should be combined as demonstrated in Annex B.
The input waveform should be a smooth waveform with the highest frequency of the noise having been reduced well below the Nyquist frequency half of the sampling frequency of the impulse array. AF- AF- X,1 X,2 X,3 X,4 X,5 s the contribution caused by the lower temperature of the reference system, s the contribution caused by the nonlinearity of the quotient, s the contribution caused by the short-term instability of the system under test, s the contribution caused by the long-term instability of the system under test, s the contribution caused by the dynamic behaviour of the system under test, s the contribution caused by the temperature variation of the system under test.
These contributions are related to normal use of the approved measuring system, and arise for example from long- term instabilities, software influence, etc. For exceptions see 4. For cases where temperature correction has been applied, the uncertainty Ugc of the temperature correction factor may be taken as the uncertainty contribution.
Instead of expressing the expanded uncertainty and coverage factor, one may find a statement on the confidence level, e. Because there is no direct correlation between unit step response parameters and correct measurement of impulse voltages, it lost its role for the requirements of this standard, but remains important for characterizing the dynamic behaviour in connection with comparison measurements 8. For the comparison of peak values a sphere gap according to lEC may be used. The relative standard uncertainty of measurement is the standard uncertainty divided by the measurand, and is therefore dimensionless.
A measuring system with several assigned measuring ranges for example a voltage divider with several low-voltage arms or different transmission systems shall be calibrated for each range or transmission system. In some cases it may, however, be necessary or desirable to evaluate uncertainties in a more complex manner. Specifically, each converting device shall be covered individually, but transmission systems and measuring instruments may be covered generically.
The result of the evaluation is summarised in Table B. NOTE 2 The measured test voltage is required to lie within the stated tolerance of the specified test level. Our prices are in Swiss francs CHF. NOTE 1 In some older standards the term “overall uncertainty” is used.
For the comparison, a reference measuring system, traceable to a National IVIetrology Institute, shall be connected in parallel with the measuring system to be calibrated.
For full and tail-chopped impulses: For the 600060-2 device and the transmission system or their combination, the scale factor shall be measured by one of the methods given below.
NOTE Attention is drawn to the possible presence of alternating voltages coupled to the measuring system and affecting the reading of the measuring instrument.
The scale factor of a measuring instrument is determined according to the relevant standard see e. Definitions and requirements for on- site testing lEC The model equation can be evaluated manually, using the equations given in Annex A, or with the aid of special software which should be validated for calculating uncertainties.
Tests for assessing contributions to uncertainty which are usually considered are summarized in Table 1. NOTE 3 Investigation of the proximity effect in the performance test is only necessary if the type test data are not sufficient.
NOTE 3 Proximity effects can be oec by corona and related space charge effects. Sufficient time should be allowed for all stages to 6006-02 before triggering the generator.
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The lead to the converting device shall carry only the current iwc the measuring system. During the actual voltage test, it is usually necessary to consider additional influencing quantities, apart from the calibration uncertainty of the scale factor stated in the calibration certificate, in order to obtain the uncertainty of measurement of the test voltage value. Comparative measurement The satisfactory performance of a reference measuring system shall be shown by calibration by comparison measurements at the relevant test voltage against a low-uncertainty reference measuring system, which is itself traceable to the standards of a National IVIetrological 60060–2.
The smoothness of the unit step response array g i is less critical if equation D.
NOTE 2 The period of voltage application should not be longer than the assigned operating time, but can be limited to a time sufficient to reach equilibrium. Such correction does however require a priori knowledge of the wave- shape, i. This third edition cancels and replaces the second edition, published inand constitutes a technical revision.
The following test report forms are related: Curve B sfiows a constant response down to direct voltage. Definitions, principles and rules I EC Scale factor of an impulse voltage measuring system component method The system for measuring lightning impulse voltages consists of an impulse divider of rated voltage 1,2 MV, a 10 bit digital recorder, and a 20 m coaxial cable.
Preview Abstract IEC The procedure given here describes the major steps of calculation. Therefore, the calculated error of the peak amplitude is often significant in comparison with the numerical error of the convolution calculation, although it may be small in comparison with the required measurement uncertainty of the peak amplitude. The limits on uncertainties of measurements stated in this standard apply to test levels stated in IEC