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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During the actual voltage test, it is usually necessary to consider additional influencing quantities, oec from the calibration uncertainty of the scale factor stated in the calibration 60060–2, in order to obtain the uncertainty of measurement of the test voltage value.
Depending on the time-positions of the overshoot and undershoot on the step response, the front part of the impulse waveform may be changed into different shapes, leading to either an increased or decreased front-time value. The uncertainty contribution related to linearity shall be considered in the calculation of measurement uncertainty when using the measuring system, see 5.
Routine tests shall be performed on each component.
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Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of ‘BIS Catalogue’ and ‘Standards: 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 front times measured with system X in the nominal epoque are too small by -0,02 as. 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. NOTE 4 Ttie simplified method of Clause 5 delivers an identical relative expanded uncertainty of the assigned scale factor. NOTE 3 A temperature correction factor for the scale factor may be used in cases where the ambient temperature varies over a wide range.
This third edition cancels and replaces the second edition, published inand constitutes a technical revision.
The equations and examples given here are valid for uncorrelated input quantities, which is often the case in high-voltage measurements. Requirements for instruments lEC Instruments and software used for measurement in high-voltage impulse tests — Part 2: NOTE 2 Preferably one measuring system is used to measure all of the required quantities, i. The compliance with type test requirements can be proved by tests on a device of the same design or sometimes be derived from manufacturer’s data.
NOTE 1 Measuring systems complying witli tfiese requirements are considered to tiave a frequency response suitable for measurement of the total harmonic distortion THD on the test voltage. Definitions and requirements for on- site testing lEC Specific terms according to the type of instrument lEC General definitions and test requirements lECInstruments and software used for measurement in high-voltage impulse tests – Part 1: It enables the user to compare and weight the measurement results, e.
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 the instrument shall record the output. NOTE 2 The resolution of a measuring instrument, e. NOTE Attention is drawn to the possible presence of alternating voltages coupled to the measuring system and affecting the reading of the measuring instrument.
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High-voltage test techniques – Partial discharge measurements I EC NOTE 2 Design and construction of any component of an approved measuring system should be such that it can withstand a disruptive discharge at the test object without any change in its characteristics. NOTE In general, the instruments used for the measurement of the test voltage value i. NOTE 2 Some test facilities may choose to 60600-2 their measuring systems for only a single set of distances, or for a few sets or ranges of distances.
Tliis can be quantified by determination of tlie scale factor at different ambient temperatures or by computations based on properties of components.
NOTE 2 In some cases a pooled estimate of variance s may be available from a large number of previous 2 p observations under well-defined conditions.
NOTE If the calibration jec performed over the full assigned measurement range 5. NOTE 2 Self-heating effect is covered by the short-term stability test.
Do you need a multi-user copy? The significant technical changes with respect to the previous edition ied as follows: The expanded uncertainty of a corrected time parameter, T,should be given according to Annex B, Example B. When the transient voltage drop during pollution testing is measured, the time constant of the measuring system shall be less than one third of the rise time of the transient. The number N of Type B uncertainty contributions may differ for the different types of test quantities Clauses 6 to 9, voltages and time parameters.
NOTE 3 The estimate of uncertainty is not very precise and high numerical precision 6006-2 not required. An approved measuring system shall have an uncertainty within the specifications of this standard throughout the ranges of operating and environmental conditions given in the record of performance. In the last line, the assigned scale factor F of the complete 6006-2 system, its combined standard uncertainty and the effective degrees of freedom are given.
NOTE No recommendations 600602 given for the measurement of voltage collapse since no lEC apparatus committee has yet specified a requirement. In the majority of cases this term is interpreted as an expanded uncertainty U with the coverage factor being equal to 2.
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. For measurements during on-site tests see IEC