Measurements of electrical quantities. General requirements

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Section 1 General Rules

Measurements of electrical quantities. General requirements

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Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

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1.6.2. Instruments for measuring electrical quantities must meet the following basic requirements:

1) the accuracy class of measuring instruments must be no worse than 2,5;

2) accuracy classes of measuring shunts, additional resistors, transformers and converters must be no worse than those given in Table. 1.6.1;

3) the measurement limits of instruments should be selected taking into account the largest possible long-term deviations of the measured values from the nominal values.

Table 1.6.1. Accuracy classes of measuring instruments

Instrument accuracy class	Shunt accuracy class, additional resistor	Transducer accuracy class	Instrument transformer accuracy class
1,0	0,5	0,5	0,5
1,5	0,5	0,5^*	0,5^*
2,5	0,5	1,0	1,0^**

* Allowed 1,0.

** 3,0 allowed.

1.6.3. The installation of measuring instruments should, as a rule, be carried out at the points from which control is carried out.

At substations and hydroelectric power plants without constant duty of operational personnel, it is allowed not to install stationary indicating devices, while places must be provided for connecting portable devices by specially trained personnel.

1.6.4. Measurements on power lines of 330 kV and above, as well as on generators and transformers, must be made continuously.

On generators and transformers of hydroelectric power plants, it is allowed to make measurements periodically using centralized control tools.

It is allowed to make measurements "on call" on a set of indicating instruments common to several connections (with the exception of those indicated in the first paragraph), as well as to use other means of centralized control.

1.6.5. When installing recording instruments in the operational circuit of the control point, it is allowed not to install indicating instruments for continuous measurement of the same quantities.

See other articles Section Rules for the installation of electrical installations (PUE).

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