IEC PAS 60044-5:2002
(Main)Instrument transformers - Part 5: Capacitor voltage transformers
Instrument transformers - Part 5: Capacitor voltage transformers
This part of International Standard IEC 60044 applies to new single-phase capacitor voltage transformers connected between line and ground for system voltages Um ³ 72,5 kV at power frequencies from 15 Hz to 100 Hz. They are intended to supply a low voltage for measurement, control and protective functions. This publication has the status of a PAS. A PAS is a technical specification not fulfilling the requirements for a standard, but made available to the public. Following publication of this PAS, the technical committee or subcommittee concerned will investigate the possibility of transforming the PAS into an International Standard.
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Standards Content (Sample)
IEC/PAS 60044-5
Edition 1.0
2002-07
Instrument transformers –
Part 5:
Capacitor voltage transformers
Transformateurs de mesure –
Partie 5:
Transformateurs condensateurs de tension
PUBLICLY AVAILABLE SPECIFICATION
INTERNATIONAL Reference number
ELECTROTECHNICAL
IEC/PAS 60044-5
COMMISSION
IEC/PAS 60044-5
Edition 1.0
2002-07
Instrument transformers –
Part 5:
Capacitor voltage transformers
Transformateurs de mesure –
Partie 5:
Transformateurs condensateurs de tension
PUBLICLY AVAILABLE SPECIFICATION
INTERNATIONAL Reference number
ELECTROTECHNICAL
IEC/PAS 60044-5
COMMISSION
– 2 – Copyright © 2002, IEC
CONTENTS
FOREWORD .5
1 Scope .6
2 Normative references .6
3 Definitions.7
3.1 General definitions .7
3.2 Capacitor voltage divider definitions .11
3.3 Electromagnetic unit definitions .13
3.4 Carrier-frequency accessories definitions .13
4 General requirements.14
5 Service conditions .14
5.1 Normal service conditions.14
5.2 Special service conditions .15
5.3 System earthing .16
6 Ratings .16
6.1 Standard values of rated frequency.16
6.2 Standard values of rated voltages.16
6.3 Standard values of rated output .17
6.4 Standard values of rated voltage factor.17
6.5 Limits of temperature rise .17
7 Design requirements .19
7.1 Insulation requirements .19
7.2 Other insulation requirements.21
7.3 Short-circuit withstand capability.24
7.4 Ferro-Resonance .24
7.5 RIV and TO requirements .25
7.6 Mechanical requirements.26
7.7 Tightness of capacitor voltage divider and electromagnetic unit.27
8 Classification of tests .27
8.1 Type
tests……………………………………………………………………………………….27
8.2 Routine tests .30
8.3 Special tests .30
8.4 Test sequence for one or two units .30
9 Type Test.30
9.1 Temperature-rise test .30
9.2 Capacitance and tanδ measurement at power-frequency.32
9.3 Short-circuit withstand capability test .32
9.4 Impulse tests.33
9.5 Wet test for outdoor capacitor voltage transformer .35
9.6 Ferro-resonance tests .35
9.7 Tightness test of a liquid-filled electromagnetic unit .36
9.8 Accuracy tests.36
9.9 Transient response test .37
9.10 Radio interference voltage test .39
10 Routine tests .40
10.1 Tightness of the liquid-filled capacitor voltage divider.40
10.2 Power-frequency withstand test and measurement of capacitance,
tanδ and partial discharge.40
10.3 Verification of terminal markings.43
10.4 Power-frequency withstand tests on the electromagnetic unit .44
10.5 Ferro-resonance check.44
10.6 Accuracy check .44
11 Special Tests .46
11.1 Measurement of the transmission factor of high frequency overvoltages.46
11.2 Mechanical strength test.46
11.3 Determination of the temperature coefficient (T ) .47
C
11.4 Tightness design test of capacitor units .47
12 Marking of the capacitor units.47
12.1 General .47
12.2 Marking .47
13 Terminal markings.47
13.1 General .47
13.2 Markings .47
14 Additional requirements for measuring capacitor voltage transformer .49
14.1 Accuracy class designation.49
14.2 Standard reference range of frequency .49
14.3 Standard accuracy classes .49
14.4 Limits of voltage error and phase displacement.49
14.5 Tests for accuracy .50
15 Additional requirements for protective capacitor voltage transformers .50
15.1 Accuracy class designation.50
15.2 Standard reference range of frequency .50
15.3 Standard accuracy classes .50
15.4 Limits of voltage error and phase displacement.51
15.5 Transient response.51
15.6 Requirements for secondary windings intended to produce a residual voltage .52
16 Rating plate.55
16.1 Markings of the rating plate .55
16.2 Example of a typical rating plate .57
17 Requirements for carrier - frequency accessories .58
17.1 General .58
17.2 Drain coil and voltage limitation device .58
17.3 Type tests .59
17.4 Routine tests .59
17.5 Marking of the rating plate .59
Annex A (normative) Typical diagram of a capacitor voltage transformer .60
Annex B (informative) Transient response of capacitor voltage transformer under fault
conditions .61
Annex C (normative) High-frequency characteristics of capacitor voltage transformers .62
Bibliography .63
Figure 1 – Altitude correction factor for the insulation.15
Figure 2 – Altitude correction factor for the temperature rise .18
Figure 3 – Flow charts test sequence to be applied when performing the type test (figure 3a)
and routine test (figure 3b).29
Figure 4 – Diagram of a capacitor voltage transformer for the transient response test using
equivalent circuit method .38
– 4 – Copyright © 2002, IEC
Figure 5 – Series burden .39
Figure 6 – Pure resistance.39
Figure 7 – Test circuit.42
Figure 8 – Alternative circuit .42
Figure 9 – Example of balanced test circuit .42
Figure 10 – Example of calibration circuit.43
Figure 11 – Example of an error diagram of class 1 CVT for accuracy check with the
equivalent circuit .45
Figure 12 – Single-phase transformer with a neutral primary terminal
and a single secondary.48
Figure 13 – Single-phase transformer with a neutral
primary terminal and with two secondaries .48
Figure 14 – Single-phase transformer with a neutral primary terminal and with two tapped
secondaries.48
Figure 15 – Single-phase transformer with a neutral primary terminal,
with one residual voltage winding and a single secondary .48
Figure 16 – Error diagram of a capacitor voltage transformer for
accuracy classes 0,2, 0,5 and 1,0 .50
Figure 17 – Transient response of a capacitor voltage transformer .51
Figure A.1 – Example of a diagram for a capacitor voltage transformer.60
Figure A.2 – Example of a diagram for a capacitor voltage transformer with
carrier-frequency accessories .60
Table 1 – Rated ambient temperature categories .14
Table 2 – Standard values of rated voltage factors for accuracy and thermal requirements .17
Table 3 – Limits of temperature rise of windings.18
Table 4 – Standard insulation levels.20
Table 5 – Partial discharge test voltages and permissible levels.22
Table 6 – Creepage distance .
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