Bami NOTE 3 The estimate of uncertainty is not very precise and tiigti numerical precision is not required. This allows a uniform treatment of both categories of uncertainties and an evaluation of a combined standard uncertainty of the measurand. The deviations of the scale factor are evaluated according to the above formula 5. The standard uncertainty of measurement has been determined in accordance with lEC For step response requirements of impulse voltage reference measuring systems, see For such cases the full range of secondary attenuators shall be calibrated separately. NOTE 2 This method is applicable to alternating voltage and to impulse voltages. Jg4 s where F.
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Bami NOTE 3 The estimate of uncertainty is not very precise and tiigti numerical precision is not required. This allows a uniform treatment of both categories of uncertainties and an evaluation of a combined standard uncertainty of the measurand. The deviations of the scale factor are evaluated according to the above formula 5.
The standard uncertainty of measurement has been determined in accordance with lEC For step response requirements of impulse voltage reference measuring systems, see For such cases the full range of secondary attenuators shall be calibrated separately. NOTE 2 This method is applicable to alternating voltage and to impulse voltages.
Jg4 s where F. Search the history of over billion web pages on the Internet. If a converting device is sensitive to proximity effects, the range of clearances where the assigned scale factor is valid shall be determined and entered in the record of performance. Its Type A iex uncertainty is equal to the experimental standard of the mean: However, if the digital recorder is then used during an impulse voltage test to obtain a single measurement value, the limited resolution needs to be considered in a Type B uncertainty.
The ratio of the reading between the measuring system and the comparison device or system, shall be established as described in 5. NOTE Long intervals between performance tests can increase the risk jec an undetected change in measurement system. NOTE 2 In general, the front times are evaluated from the same records of N and X, iiec to evaluate the peak values for determining the scale factor 5.
NOTE Performance can be investigated using convolution techniques. Definitions, principles and rules I EC The output of the measuring system shall be compared with a device or system that has proven its linearity or can be presumed to be linear over the full voltage range see 5.
The result of the evaluation is summarised in Table B. 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.
In both cases the comparison shall be made in accordance with the provisions of lEC For example influence quantities mentioned in clause 5 include temperature and proximity effects. 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. Tests for assessing contributions to uncertainty which are usually considered are summarized in Table 5. NOTE To ensure that the influence of leakage current is negligible, a measuring current as high as 0,5 mA at the rated voltage may be necessary.
NOTE 2 A transmission system may be partially or completely included in the converting device or in the measuring instrument. For dated references, only the edition cited applies. NOTE 1 In order to reproduce, in the recorded curve, oscillations that may be superimposed on an impulse, the relevant ie limit frequency may be several MHz. Correlation will not be discussed jec in this standard. The limits on uncertainties of measurements stated in this standard apply to levels stated in lEC The standard uncertainty Type A lec the time parameter measurement is obtained as the largest of the single standard uncertainties determined for the different T.
A measuring system can also be approved for a range of fundamental frequencies e. The resolution does not need to be considered again, in full, but rather only in a small portion as a residual Type B uncertainty. An interfering condition shall be produced at the input of the measuring system by a disruptive discharge with an impulse voltage representative of voltage, shape and instant of a possible discharge to be applied during the HV tests, and jec instrument shall ied the output.
CARDAX PDF The dynamic behaviour is determined from the step response of the measuring system recorded according to Annex C and from convolution of the recorded step response with the nominal waveforms for which is sought.
It is applicable for other time parameters in the same way. Alternatively the test of In the majority of cases this term is interpreted as an expanded uncertainty U with the coverage factor being equal to iev. Taking correlation into account is thus mainly essential for sophisticated uncertainty analysis to achieve a very accurate estimation of uncertainty.
For example, a voltage divider is characterized by the voltage ratio and its uncertainty in the assigned measurement ranges used. General definitions and test requirements lECInstruments and software used for measurement in high-voltage impulse tests — Part 1: These contributions are related to the reference measuring system, and arise from non-linearity, short- and long-term instabilities, etc.
TC 42 — High-voltage and high-current test techniques rss. The record of performance shall uniquely identify the components of the measuring system and shall be structured so that performance of the measuring system can be traced over Alternatively, any user may choose to have the performance tests by a National IVIetrology Institute or by a Calibration Laboratory accredited for the quantity to be calibrated.
Mgo is the non-linearity contribution to standard ieec determined during calibration of the scale factor see 5. Conditions significant for the result of the calibration of the approved measuring system shall be included in the record of performance.
In cases where a number of performance test results are available, the long-term stability can be characterised by the type A contribution: Otherwise a value A: Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken up for revision.
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