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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Details of test or calculations shall be included in the record of performance. For measurements during on-site tests see IEC NOTE 1 Care should be taken to ensure that the appropriate “stray” capacitance or coupling and the mutual influence of the components are included in the measurement.

However, this estimation may be given for defined range of measuring conditions in conjunction with the calibration certificate. In all cases, the user siiall include the test data into the record of performance. The lead to the converting device shall carry only the current to the measuring system. The principles of this standard apply also to higher levels but the uncertainty may be greater.

In this case kec measuring system may be approved for measurements of peak voltage and time parameters while an auxiliary system is approved for measurements of oscillations. NOTE 2 The resolution of a measuring instrument, e.

General definitions and test requirements lECInstruments and software used for measurement in high-voltage impulse tests – Part 1: The recorder’s step response is rather flat, and it can be concluded that the scale factor does not depend on the time parameters within the tolerances specified for lightning impulse voltages. This can be done by evaluation of a set of test data with established reference values. It is used for computer-aided calculation using digital impulse waveforms. Alternatively it can be determined from the scale factors of the components 5.

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Review of Indian Standards Amendments are issued to standards as the need arises on the basis of comments. The result of the evaluation is an estimate of a change of the scale factor. We accept all major credit cards American Express, Mastercard and VisaPayPal and bank transfers as form of payment. The experimental proof can be given either by the comparison method or by the component method. The results of the type and routine tests can be taken from manufacturer’s data. The law of propagation of uncertainty thus applies to both types of the model function for uncorrelated input quantities.

Mj,g is the combined standard uncertainty of the mean front time error, Ar. The calculated error in the peak amplitude can be compared to the unit step response to verify if the convolution calculation has been performed correctly.

The equations and examples given here are valid for uncorrelated input quantities, which is often the case in high-voltage measurements. The procedure given here describes the major steps of calculation. The expanded uncertainty of a corrected time parameter, T,should be given according to Annex B, Example B. As the evaluation itself is not an exact science leading to one single solution, it is not uncommon that experienced test engineers may judge the measurement process in a different manner and obtain different Type B uncertainty values.

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Tliis can be quantified by determination of tlie scale factor at different ambient temperatures or by computations based on properties of components.

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The significant technical changes with respect to the previous edition are as follows: The maximum deviation is a. Other contributions can be important in some cases and shall be considered in addition. 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, oec is taken up for revision.

NOTE 2 The measured test voltage is required to lie within the stated tolerance of the specified test level.

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NOTE 2 For measuring systems that display the value of the input quantity directly, the nominal scale factor of the measuring system is unity. In general, the measurand to be considered is the scale factor of the measuring system, but in some cases other quantities, such as the time parameters of an impulse voltage and their associated errors, should also be considered.

These contributions are related to normal use of the approved measuring system, and arise for isc from long- term instabilities, software influence, etc. The uncertainty limits shall not be exceeded in the presence of ripple, lec magnitude of which is within the limits given in lEC