IEC TR 61869-102:2014

Instrument transformers - Part 102: Ferroresonance oscillations in substations with inductive voltage transformers

IEC/TR 61869-102:2014(E) provides technical information for understanding the undesirable phenomenon of ferroresonance oscillations in medium voltage and high voltage networks in connection with inductive voltage transformers. Ferroresonance can cause considerable damage to voltage transformers and other equipment. Ferroresonance oscillations may also occur with other non-linear inductive components.

General Information

• Status: Published
• Publication Date: 20-Jan-2014
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• Technical Committee: TC 38 - Instrument Transformers
• Current Stage: PPUB - Publication issued
• Start Date: 15-Feb-2014
• Completion Date: 21-Jan-2014

Standards Content (Sample)

IEC TR 61869-102 ®
Edition 1.0 2014-01
TECHNICAL
REPORT
colour
inside
Instrument transformers –
Part 102: Ferroresonance oscillations in substations with inductive voltage
transformers
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IEC TR 61869-102 ®
Edition 1.0 2014-01
TECHNICAL
REPORT
colour
inside
Instrument transformers –
Part 102: Ferroresonance oscillations in substations with inductive voltage

transformers
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XA
ICS 17.220.20 ISBN 978-2-8322-1308-7

– 2 – TR 61869-102 © IEC:2014(E)
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Introduction to ferroresonance oscillations . 8
3.1 Definition of ferroresonance . 8
3.2 Excitation of steady state and non-steady state ferroresonance
oscillations . 10
4 Single phase and three phase oscillations . 12
4.1 Single phase ferroresonance oscillations . 12
4.2 The simplified circuit for the single phase ferroresonance oscillations . 13
4.3 Capacitive voltage transformers . 15
4.4 Three-phase ferroresonance oscillations . 15
4.4.1 General . 15
4.4.2 Configuration . 15
4.4.3 Ferroresonance generation . 16
4.4.4 Resulting waveform of ferroresonance oscillation . 16
4.4.5 Typical oscillogram of three phase ferroresonance . 19
5 Examples of ferroresonance configurations . 20
5.1 Single-phase ferroresonance power line field in a 245 kV outdoor
substation . 20
5.2 Single phase ferroresonance oscillations due to line coupling . 22
5.3 Three-phase ferroresonance oscillations . 25
6 Inductive voltage transformer (key parts) . 26
7 The circuit of the single-phase ferroresonance configuration . 28
7.1 Schematic diagram . 28
7.2 Magnetisation characteristic . 29
7.3 Circuit losses . 30
8 Necessary information for ferroresonance investigation . 31
8.1 General . 31
8.2 Single phase ferroresonance. 31
8.3 Three phase ferroresonance . 32
9 Computer simulation of ferroresonance oscillations . 33
9.1 General . 33
9.2 Electrical circuit and circuit elements . 33
9.3 Circuit losses . 33
9.4 Examples of simulation results for single phase ferroresonance
oscillations . 33
9.4.1 General . 33
9.4.2 Case 1: Transient, decreasing ferroresonance oscillation . 34
9.4.3 Case 2: Steady-state ferroresonance oscillation at network
frequency . 34
9.4.4 Case 3: Steady-state subharmonic ferroresonance oscillation. 35
9.4.5 Case 4: Steady-state chaotic ferroresonance oscillation . 36
9.5 Simulation of three phase ferroresonance . 37

TR 61869-102 © IEC:2014(E) – 3 –
10 Experimental investigations, test methods and practical measurements. 38
10.1 General . 38
10.2 Single-phase ferroresonance oscillations . 38
10.3 Three-phase ferroresonance oscillations . 41
11 Avoidance and suppression of ferroresonance oscillations . 42
11.1 Flow diagram . 42
11.2 Existing substations . 44
11.3 New projects . 44
11.4 Avoidance of ferroresonance oscillations . 44
11.4.1 General . 44
11.4.2 Single phase ferroresonance oscillations . 44
11.4.3 Three phase ferroresonance oscillations . 45
11.5 Damping of ferroresonance oscillation . 45
11.5.1 General . 45
11.5.2 Single-phase ferroresonance oscillations . 45
11.5.3 Three-phase-ferroresonance oscillations . 47
Annex A (informative) Oscillations in non-linear circuits . 49
A.1 Overview . 49
A.2 The simplification of non-linear electrical circuits with the theorem of
Thévenin . 51
A.3 The differential equation for ferroresonance oscillations . 51
A.4 Oscillation frequencies in ferroresonance systems . 53
Bibliography . 54

Figure 1 – Example of a typical magnetisation characteristic of a ferromagnetic core . 9
Figure 2 – Schematic diagram of the simplest ferroresonance circuit . 9
Figure 3 – Examples of measured single-phase ferroresonance oscillation with
16 / Hz oscillation . 11
Figure 4 – Schematic diagram of a de-energised outgoing feeder bay with voltage
transformers as an example in which single-phase ferroresonance oscillations can
occur . 12
Figure 5 – Diagram of a network situation that tends toward single-phase
ferroresonance oscillations, in which they can be excited and maintained over the
capacitive coupling of parallel overhead power line systems . 13
Figure 6 – Electrical circuits for theoretical analysis of a single-phase ferroresonance
oscillation . 14
Figure 7 – Insulated network as an example of a schematic diagram of a situation in
which a three-phase ferroresonance oscillation can occur . 15
Figure 8 – Phasor diagram to explain the oscillation of the earth potential . 16
Figure 9 – Laboratory test set used by Bergmann . 17
Figure 10 – Domains in the capacitance C and line voltage U where different harmonic
and sub-harmonic ferroresonance oscillations are obtained for a given resistance R of
6,7 Ω in Bergmann’s test set . 18
Figure 11 – Domains in the capacitance C and line voltage U where second sub-
harmonic ferroresonance oscillations are obtained for a variation of the resistance R in
Bergmann’s test set . 18
Figure 12 – Domains in the capacitance C and line voltage U where different modes of
second sub-harmonic ferroresonance oscillations are obtained for a given resistance R
of 6,7 Ω in Bergmann’s test set . 19
Figure 13 – Fault recorder display of a three-phase ferroresonance oscillation . 20

– 4 – TR 61869-102 © IEC:2014(E)
Figure 14 – Switching fields in the 245 kV substation in which single-phase
ferroresonances occur . 21
Figure 15 – Examples of oscillations of single-phase ferroresonance when switching off
the circuit breaker in Figure 14 . 22
Figure 16 – Single-phase schematic of the network situation on the 60 kV voltage level
in the area of substations 1, 2, and 3 . 23
Figure 17 – Tower schematic of the common stretch of overhead lines between
substations 1 and 2 . 24
Figure 18 – Ferroresonance oscillations recorded in line no. 5 at Substation 2 . 24
Figure 19 – Single-line diagram of th
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