IEC TS 60034-27-5:2021

Rotating electrical machines - Part 27-5: Off-line measurement of partial discharge inception voltage on winding insulation under repetitive impulse voltage

IEC TS 60034-27-5:2021 provides an off-line measurement method of the partial discharge inception and extinction voltage on winding insulation under repetitive impulse voltage. This document is relevant to rotating machines supplied by a voltage source converter.

General Information

• Status: Published
• Publication Date: 06-Apr-2021
• ICS: 29.120.30 - Plugs, socket-outlets, couplers
• ICS: 29.160.01 - Rotating machinery in general
• Technical Committee: TC 2 - Rotating machinery
• Drafting Committee: MT 10 - TC 2/MT 10
• Current Stage: PPUB - Publication issued
• Start Date: 06-May-2021
• Completion Date: 07-Apr-2021

Standards Content (Sample)

IEC TS 60034-27-5 ®
Edition 1.0 2021-04
TECHNICAL
SPECIFICATION
colour
inside
Rotating electrical machines –
Part 27-5: Off-line measurement of partial discharge inception voltage on
winding insulation under repetitive impulse voltage
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IEC TS 60034-27-5 ®
Edition 1.0 2021-04
TECHNICAL
SPECIFICATION
colour
inside
Rotating electrical machines –

Part 27-5: Off-line measurement of partial discharge inception voltage on

winding insulation under repetitive impulse voltage

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.160.01 ISBN 978-2-8322-9648-6

– 2 – IEC TS 60034-27-5:2021 © IEC 2021
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, symbols and abbreviated terms . 8
4 Repetitive impulse voltages for PD measurement . 11
4.1 General . 11
4.2 Waveform of single impulse voltage . 12
4.2.1 Waveform at impulse generator terminal without test object . 12
4.2.2 Typical distortions of impulse waveform at the terminals of test object . 14
4.3 Train of single impulse voltage . 17
4.4 Step-by-step voltage increase and decrease using trains of single impulse
voltage . 18
4.5 Impulse voltage distribution inside rotating machines . 22
5 PD measurement methods with impulse voltage . 23
5.1 General . 23
5.2 Electrical PD measurements . 23
5.2.1 General . 23
5.2.2 Coupling capacitor with higher order analogue filter . 23
5.2.3 HFCT with higher order analogue filter . 24
5.2.4 Electromagnetic couplers . 25
5.3 Threshold level of PD detection . 26
5.4 Measuring system with impulse generator and computer . 27
5.5 Calculation and interpretation of RPDIV and RPDEV . 27
6 Impulse PD test procedure . 28
6.1 Test object . 28
6.1.1 Twisted-pair or equivalent . 28
6.1.2 Motorette or formette . 29
6.1.3 Complete winding and connection . 29
6.2 Safety and environment during PD test . 31
6.2.1 Grounding and floating of test objects during tests . 31
6.2.2 Environment during test . 31
6.3 Test procedure and reports . 32
Annex A (informative) Typical PD measurements on a complete winding . 33
Annex B (informative) Example of PD data analysis using phase angle . 35
Annex C (informative) Example of connection of complete windings . 37
C.1 General . 37
C.2 Connections for three-terminal machines . 37
C.3 Connections for four-terminal machines . 40
Annex D (informative) Example of SBS voltage increase pattern of repetitive impulse . 41
Bibliography . 42

Figure 1 – Block representation of measurement circuit for RPDIV and RPDEV . 11
Figure 2 – Simplified impulse generator (IG) circuit with a single switch S . 12
Figure 3 – Output voltage at open terminal of IG with single switch . 13

Figure 4 – Two impulses at open terminal of IG with single switch . 13
Figure 5 – Simplified IG circuit with four-arm (switch) bridge circuit . 13
Figure 6 – Output voltages at open terminal of four-arm bridge circuit . 14
Figure 7 – Increase of rise time and decrease of peak voltage of triangular impulse . 15
Figure 8 – Increase of rise time and decrease of peak voltage of rectangular impulse. 15
Figure 9 – Overshoot of peak and following fast oscillation of triangular impulse . 15
Figure 10 – Overshoot of peak and following fast oscillation of rectangular impulse . 16
Figure 11 – Typical "ringing" observed during bipolar rectangular voltage test . 16
Figure 12 – Slow oscillating decay of triangular impulse . 17
Figure 13 – Slow oscillating decay of rectangular impulse . 17
Figure 14 – Schematic representation of train parameters of positive unipolar impulses . 18
Figure 15 – Schematic representation of train parameters of bipolar impulses . 18
Figure 16 – SBS parameters of positive unipolar impulses . 19
Figure 17 – SBS voltage pattern of positive unipolar impulses for RPDIV and RPDEV . 19
Figure 18 – SBS voltage pattern of bipolarly distorted positive unipolar impulse . 20
Figure 19 – SBS voltage increase of bipolar impulses . 20
Figure 20 – Representative scheme of conditioning procedure before RPDIV
measurement . 21
Figure 21 – Schematic representation of phase/phase, phase/ground and turn/turn

voltages of the winding of a rotating machine fed from a two-level converter [2] . 23
Figure 22 – Coupling capacitor with higher order analogue filter . 24
Figure 23 – Example of voltage impulse and PD pulse frequency spectra before (left)
and after (right) filtering . 24
Figure 24 – HFCT between supply and test object with higher order analogue filter . 25
Figure 25 – HFCT between test object and earth with higher order analogue filter . 25
Figure 26 – Circuit using an electromagnetic coupler (for example an antenna) to
suppress impulses from the test supply . 25
Figure 27 – Circuit using an electromagnetic UHF antenna . 26
Figure 28 – Schematic representation of noise, disturbance and threshold values . 26
Figure 29 – Example diagram of PD measurements with PC . 27
Figure 30 – Example of RPDIV and RPDEV calculation using a 50 % PD probability

against repetitive impulse voltage (Figure 12 of IEC TS 61934:2011, modified). 28
Figure 31 – Representative scheme of voltage terminals for three-terminal machine
and four-terminal machine . 30
Figure A.1 – Block diagram of PD measurement system used in RRT . 33
Figure A.2 – Impulse pattern used in RRT and PD inception . 33
Figure B.1 – Example of PD phase angle pattern of sinusoidal voltage . 35
Figure B.2 – Example of PD phase angle pattern of PWM voltage on the phase angle
of a sinusoidal one . 36
Figure B.3 – Example of PD phase angle pattern of PWM voltage on rectangular
voltage angle (PRPD pattern) . 36
Figure C.1 – Connection of six-terminal machines. 37
Figure C.2 – Connection of three- or four-terminal machines (with N terminal) . 37
Figure C.3 – Three-terminal machine connection, Type A (Table 2) . 38
Figure C.4 – Three-terminal machine connection, Type B (Table 2) . 38
Figure C.5 – Three-terminal machine connection, Type C (Table 2) . 38

– 4 – IEC TS 60034-27-5:2021 © IEC 2021
Figure C.6 – Three-terminal machine connection, Type D (Table 2) . 39
Figure C.7 – Three-terminal machine connection, Type E (Table 2) . 39
Figure C.8 – Three-terminal machine connection, Type F (Table 2) . 39
Figure C.9 – Four-terminal machine with earthed N terminal – Connection types
(Table 3) . 40
Figure D.1 – SBS voltage increase of alternating train of unipolar impulses . 41

Table 1 – Typical ranges of impulse voltage parameters at terminal of test object to be
reported . 21
Table 2 – Connection of complete winding of three-terminal machine . 30
Table 3 – Connection of complete winding of four-terminal machine . 31
Table A.1 – Parameters used in RRT . 33

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