IEC 60270:2000/AMD1:2015

Amendment 1 - High-voltage test techniques - Partial discharge measurements

Amendement 1 - Techniques des essais à haute tension - Mesures des décharges partielles

General Information

• Status: Published
• Publication Date: 26-Nov-2015
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 19.080 - Electrical and electronic testing
• Technical Committee: TC 42 - High-voltage and high-current test techniques
• Drafting Committee: MT 17 - TC 42/MT 17
• Current Stage: PPUB - Publication issued
• Start Date: 27-Nov-2015
• Completion Date: 15-Dec-2015

Relations

• Amends: IEC 60270:2000 - High-voltage test techniques - Partial discharge measurements
• Effective Date: 05-Sep-2023
• Revised: IEC 60270:2025 - High-voltage test techniques – Charge-based measurement of partial discharges
• Effective Date: 05-Sep-2023

Overview

IEC 60270:2000/AMD1:2015 is an important amendment to the international standard for high-voltage test techniques focusing on partial discharge (PD) measurements. Developed by the IEC Technical Committee 42, it provides updated definitions, testing methodologies, calibration procedures, and measurement system requirements to improve accuracy and consistency in assessing insulation quality in electrical equipment.

Partial discharges are localized dielectric breakdowns in electrical insulation that do not completely bridge the space between conductive electrodes. Detecting and measuring PDs is crucial for maintaining the reliability and longevity of high-voltage apparatus such as transformers, cables, and electrical machines.

This amendment enhances IEC 60270:2000 by refining PD-related terms, improving calibration methods, and specifying parameters for both analogue and digital PD instruments.

Key Topics

• Updated Terms and Definitions
  The amendment refines key terminology including:

  • Digital partial discharge instruments: Devices performing digital acquisition and analysis of PD signals.
  • Accumulated apparent charge: Sum of apparent charge from PD pulses exceeding a threshold over a given time.
  • PD pulse count: Total PD pulses above a threshold within a specified interval.
  • PD pattern: Graph of apparent charge versus phase angle of PD pulses.

• Measurement Frequency Parameters
  Recommended frequency bands for PD measurement instruments are clarified:

  • Significant frequency range between 30 kHz and 100 kHz.
  • Upper frequency limit potentially reduced below 1 MHz for equipment like transformers and electrical machines as per relevant technical guidelines.

• Calibration Procedures & Equipment
  Detailed procedures are described to calibrate PD measurement instruments using step voltage techniques. The amendment:

  • Specifies rise time, step voltage duration, and steady-state requirements for calibrators.
  • Introduces methods for numerical integration and step voltage response to determine calibration charge.
  • Addresses challenges with long lead connections and stray capacitances during calibration.

• PD Measurement Quantities and Test Circuits
  Essential quantities for PD assessment under direct voltage are defined:

  • Apparent charge per PD pulse.
  • Accumulated apparent charge over pulse trains.
  • PD pulse count statistics with noise considerations.

  The amendment also defines standardized circuits for measuring apparent charge using analogue or digital systems, ensuring consistent and reliable PD results.

• Digital Acquisition Guidelines
  Annex E provides guidance for digital processing of PD signals captured at high-voltage terminals, detailing both analogue and digital signal pathway components, enhancing data accuracy and interpretation.

Applications

The IEC 60270:2000/AMD1:2015 amendment is invaluable to professionals involved in:

• High-voltage insulation diagnostics
  Partial discharge measurement helps detect insulation defects before failure, particularly in transformers, cables, switchgear, and rotating machines.

• Quality control in manufacturing
  PD testing during production cycles ensures insulation integrity and minimizes premature equipment failure.

• Routine maintenance and condition monitoring
  Utilities and industrial plants use PD measurements to evaluate aging and degradation of electrical assets, enabling preventive maintenance.

• Research and development
  Improves test setup standardization for evaluating new insulation materials and high-voltage equipment designs.

By following this amendment, stakeholders can achieve more accurate, reproducible, and internationally consistent PD assessments, optimizing asset management and safety.

Related Standards

• IEC 60060-1 – High-voltage test techniques – General definitions and test requirements.
• IEC 60270 (original edition) – High-voltage test techniques – Partial discharge measurements (base standard).
• IEC 61860 – High-voltage test techniques related to gas-insulated substations.
• IEEE Std 400 – IEEE guide for partial discharge testing of electrical apparatus.
• IEC 61083 – Partial discharge measuring systems.
• IEC 60599 – Interpretation of dissolved gas analysis in transformer oils (complementary for diagnostics).

Adherence to IEC 60270:2000/AMD1:2015 alongside these related standards ensures comprehensive, harmonized testing protocols for high-voltage equipment worldwide.

---

Keywords: IEC 60270 amendment, partial discharge measurement, high-voltage test techniques, PD instruments calibration, digital partial discharge, electrical insulation diagnostics, high-voltage equipment testing, IEC standards, power transformer insulation, electrical machine testing

Standards Content (Sample)

IEC 60270 ®
Edition 3.0 2015-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
AM ENDMENT 1
AM ENDEMENT 1
High-voltage test techniques – Partial discharge measurements

Techniques des essais à haute tension – Mesures des décharges partielles

IEC 60270:2000-12/AMD1:2015-11(en-fr)

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IEC 60270 ®
Edition 3.0 2015-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
AM ENDMENT 1
AM ENDEMENT 1
High-voltage test techniques – Partial discharge measurements

Techniques des essais à haute tension – Mesures des décharges partielles

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.20; 19.080 ISBN 978-2-8322-3013-8

– 2 – IEC 60270:2000/AMD1:2015
© IEC2015
FOREWORD
This amendment has been prepared by IEC technical committee 42: High-voltage and high
current test techniques.
The text of this amendment is based on the following documents:
FDIS Report on voting
42/338/FDIS 42/340/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC website under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
_____________
3 Definitions
Replace the existing title and introductory phrase with the following new title and introductory
phrase:
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
Replace the existing definition 3.10 with the following new definition 3.10:
3.10
digital partial discharge instruments
instruments which perform a digital acquisition and evaluation of the PD data
Note 1 to entry: The A/D conversion of the PD pulses captured from the terminals of the test object can be done
either directly or after the apparent charge pulses have been established employing either an analogue band-pass
filter amplifier or an active integrator (see Annex E).

© IEC2015
Add the following new definitions:
3.12
accumulated apparent charge q
a
sum of the apparent charge q of all individual pulses exceeding a specified threshold level,
and occurring during a specified time interval ∆t
3.13
PD pulse count m
total number of PD pulses which exceed a specified threshold level within a specified time
interval ∆t
3.14
PD pattern
display of the apparent charge q versus the phase angle φ of the PD pulses recorded during
i
a specified time interval ∆t
4.3.4 Wide-band PD instruments
Replace the last sentence of 4.3.4 with the following new text:
Recommended values for the significant frequency parameters f , f and ∆f are:
1 2
30 kHz ≤ f ≤ 100 kHz
f ≤ 1 MHz
100 kHz ≤ ∆f ≤ 900 kHz
Renumber the existing "NOTE" in 4.3.4 to "NOTE 1" and add the following new "NOTE 2":
NOTE 2 For test objects with windings like transformers and electrical machines the acquired frequency band may
be reduced down to a few 100 kHz and even below. The upper limit frequency f to be accepted for such kinds of
test objects should be specified by the relevant Technical Committee.
5.2 Calibration procedure
Renumber the existing "NOTE" in 5.2 to "NOTE 1" and add the following new "NOTE 2" at the
end of the subclause:
NOTE 2 For tall test objects, the connection leads between calibrator and terminals of the test object might
exceed several meters. Thus the transfer of the charge from the calibrator to the test object may be reduced due to
inevitable stray capacitances. The measurement uncertainty acceptable under this condition should be specified by
the relevant Technical Committee.
6.1 General
Replace the existing third paragraph "The voltage pulses of the generator shall have a rise
time t of less than 60 ns." with the following new text:
r
The parameters characterizing unipolar step voltage of magnitude U shall satisfy the
following conditions (see Figure 6):
Rise time:     t ≤ 60 ns
r
Time to steady state:    t ≤ 200 ns
s
Step voltage duration:    t ≥ 5 µs
d
Deviation of the step voltage magnitude U between t and t : ∆U ≤ 0.03 U

0 s d 0
, t and t are measured from the origin t of the step voltage which
The time parameters t
r s d 0
refers to the time instant when the rising voltage equals 10 % of U (see Figure 6).
– 4 – IEC 60270:2000/AMD1:2015
© IEC2015
The time to steady state t is the shortest instant at which the deviation ∆U from U remains
s 0
first time less than 3 %.
The step voltage duration t is the instant after t at which the magnitude of the step voltage
d s
decays below 97% of U . After t the voltage shall decrease continuously down to 10 % of U
,
0 d 0
within a time interval not shorter than 500 µs.
The magnitude U of the step voltage is the mean value occurring within the steady state
duration t − t .
d s
For test objects represented by a lumped capacitance C the calibrating capacitor C shall
a 0
satisfy the conditions C ≤ 200 pF and C ≤ 0,01 C .

0 0 a
For test objects represented by a characteristic impedance Z , such as power cables
c
exceeding a length of 200 m, the value of the calibrating capacitor shall satisfy the conditions
C ≤ 1nF and C × Z ≤ 30 ns.
0 0 c
For calibrators manufactured before this amendment was published, whose time and voltage
parameters do not comply with the above specified values, the deviation of the measured
values from the specified values shall be stated in the test protocol.
11.2 Quantities related to partial discharges
Replace the existing title and text of 11.2 with the following new title and text:
11.2 PD quantities
PD measurements with direct voltage should be based on the following quantities:
– apparent charge of each individual PD pulse occurring during a specified time interval ∆t
i
at constant test voltage, as defined in 3.3.1 (see Figure H.1a)).
– accumulated apparent charge of a PD pulse train occurring within a specified time interval
∆t at constant test voltage, as defined in 3.12 (see Figure H.1b)).
i
– PD pulse count m of PD pulse trains as defined in 3.13 exceeding specified limits of the
apparent charge magnitude q during a specified time interval ∆t at constant test voltage
m i
level (see Figure H.2a)).
– PD pulse count m occurring within specified ranges of the apparent charge magnitude q
m
for a specified time interval ∆t at constant test voltage level (see Figure H.2b)).
i
To determine the PD pulse count m care should be taken so that noisy pulses are not counted
to avoid misleading statistics. Thus before starting the actual PD measurement the
background noise level in terms of pC shall be determined. Based on this the apparent charge
threshold level shall be adjusted to at least twice the background noise.
Values for the PD quantities listed above shall be specified by the relevant Technical
Committee.
11.4 Test circuits and measuring systems
Replace the existing text with the following new text:
To measure the apparent charge according to 3.3.1, the basic circuits shown in Figure 1a to
Figure 1d shall be used in conjunction with either analogue or digital PD measuring systems,
as described in 4.3 and 4.4 and Annex E. The PD instruments applied shall have a pulse train
response that is independent of the repetition rate of PD pulses.

© IEC2015
To indicate the PD pulse count m, the application of either digital PD instruments with
integrated pulse counters or analogue PD instruments in combination with suitable pulse
counting devices is recommended.
The calibration procedures recommended in Clause 5 and the calibrators specified in
Clause 6 can also be applied for testing with direct voltage.
Add, after Figure 5, the following new Figure 6:
U + ΔU
1 U
U – ΔU
0,9 U
0,1 U
t
r
t
t
s
t
d
IEC
t
Key
U step voltage magnitude t step voltage duration
0 d
t origin of the step voltage (t − t ) steady state duration
0 d s
t rise time of the step voltage ∆U absolute voltage deviation from U
r
t time to steady state
s
Figure 6 – Step voltage parameters of a calibrator
A.3 Alternative method
Replace the existing title of Clause A.3 with the following new title:
A.3 Numerical integration method
Add, at the end of Clause A.3, the following new text:
The voltage and time parameters of the step voltage specified in 6.1 and in Figure 6 can be
determined if the current through the calibration capacitor C caused by the voltage step U is
0 0
measured by means of a resistive shunt R (see Figure A.2). For example, this shunt can be
m
a 50 Ω feed-through low-inductive termination. Under this condition the calibrating charge can
be determined based on a numerical integration of the time dependent voltage signal u (t)
r
appearing across R . Care shall be taken on the offset voltage which shall be adjusted
m
exactly to zero to avoid an integration error.

U
– 6 – IEC 60270:2000/AMD1:2015
© IEC2015
C
U R u (t)
0 m r
Calibrator Oscilloscope
IEC
Figure A.2 – Setup for performance tests of calibrators using the numerical integration
Add, at the end of Annex A, the following new Clause A.4:
A.4 Step voltage response method
The charge q generated by the calibrator can also be determined by measuring the transient
voltage appearing across a measuring capacitor C using the circuit shown in Figure A.3 and
m
[1] . As the series connection of C and C comprises a voltage divider, the magnitude U of
0 m c
the time dependent voltage u (t), which occurs across C at steady state condition, is direct
c m
proportional to the step voltage magnitude U generated by the calibrator:
U = U × C / (C + C )
c 0 0 0 m
The charge q transferred from the calibrator to the measuring capacitor C can thus be
c m
expressed by:
q = q / (1 + C /C )
c 0 0 m
Under the condition C >> C the charge q injected into C becomes equal to that charge

m 0 c m
amount q created by the calibrator:
q ≈ q U × C
≈
0 c c m
To ensure a measurement uncertainty below 3 %, the capacitance of C should be selected
m
not below 10 nF including both the capacitance of the connecting cable and the input
capacitance of the oscilloscope. Under this condition a calibrating charge of q = 100 pC
would cause a step voltage magnitude of U ≈10 mV which can be measured at the desired
c
uncertainty using commercially available digital oscilloscopes, in particular if the averaging
mode is adopted. For calibrating charges q <100 pC an active integration of the total current
flowing through C is recommended to enhance the signal magnitude being recorded by the
oscilloscope in order to ensure the specified measuring uncertainty. For more information in
this respect see reference [1].

_______________
Numbers in square brackets refer to the Bibliography.

© IEC2015
R
s
C
u (t)
U c
C
m
Calibrator Oscilloscope
IEC
Figure A.3 – Setup for performance tests of calibrators using the step voltage method
The circuit shown in Figure A.3 can also be used for the determination of the significant time
parameters presented in 6.1 and illustrated in Figure 6. As the series connection of C and C
0 m
comprises a voltage divider, the time dependent voltage u (t) appearing across C is direct
m
c
proportional to the time dependent voltage generated by the calibrator. For such
measurements C should also be chosen in the order of 10 nF, as recommended for the
m
determination of the calibrating charge. Moreover, C should be connected as close as
m
possible to the input of the oscilloscope. Otherwise superimposed oscillations might be
excited, as displayed in Figure A.4. To attenuate such disturbing oscillations, an additional
series resistor R in the order of 100 Ω should be connected as closely as possible to the
s
output of the calibrator. Moreover, the connection leads between calibrator and oscilloscope
should not exceed a length of 1 m.
IEC
IEC
a) R = 10 Ω b) R = 100 Ω
s s
voltage scale: 20 mV/div; time scale: 40 ns/div
Figure A.4 – Impact of the series resistor R on the step voltage response appearing
s
across C using the circuit according to Figure A.3, where the oscilloscope was
m
connected to the calibrator via a 50 𝛀 measuring cable of 1 m long.

U
c
– 8 – IEC 60270:2000/AMD1:2015
© IEC2015
Annex E – Guidelines to digital acquisition of partial discharge quantities
Replace the existing title of Annex E with the following new title:
Annex E
(informative)
PD measuring instruments
E.1 General
Add, at the beginning of Clause E.1, the following new text:
For processing the PD signal captured from the terminals of the test object by means of a
coupling device, comprising a coupling capacitor in combination with a measuring impedance,
both the analogue or digital PD signal processing can be applied. The major units of both
analogue and digital PD instruments are shown in the Figures E.2 and E.3 respectively.
Additionally to the PD pulse trains, an AC signal derived from the test voltage should be
digitized to enable the display of characteristic phase-resolved PD patterns, as displayed in
Figure E.4
E.3 Recommendations for recording test voltage, phase angle φ and time t of
i i
occurrence of a PD pulse
Add, at the end of the Clause E.3, after the existing Figure E.1, the following new Figure E.2,
Figure E.3 and Figure E.4.
PD Signal
pC
1 2 3 4 5
CH1
AC Voltage signal
CH2
IEC
Key
1 Attenuator 4 Peak detector and evaluation unit
2 Amplifier 5 Reading instrument
3 Electronic Integrator 6 Visualization unit
Figure E.2 – Block diagram of an analogue PD instrument
equipped with an electronic integrator

© IEC2015
PD Pulse
Digital signal
processing
A D
Memory
f f
1 2
1 2 3 4
386 pC
Reporting
AC Voltage signal
127 kV
Phase
A D
synchronization 54 min
Control
6 7
IEC
Key
1 Attenuator 4 Numerical integrator
2 A/D converter for PD pulses voltage 5 A/D converter for AC
3 Digital band-pass filter 6 Acquisition unit
7 Evaluation and visualization unit
a) Direct A/D conversion of the input PD pulses
Digital signal
PD Pulse
processing
A D
Memory
1 2 3 4
386 pC
Reporting
AC Voltage signal 127 kV
Phase
A D
synchronization 54 min
Control
6 7
IEC
Key
1 Attenuator 4 A/D converter for apparent charge pulses
2 Amplifier 5 A/D converter for AC voltage signal
3 Band-pass filter 6 Acquisition unit
7 Evaluation and visualization unit
b) A/D conversion after the integration of the input PD pulses by means
of a band-pass filter has been performed
Figure E.3 – Block diagram of digital PD instruments

– 10 – IEC 60270:2000/AMD1:2015
© IEC2015
IEC
NOTE The PD pulses occurring during the negative half-cycle of the test voltage have been inverted which appear
thus like positive pulses. Due to the large scattering PD magnitudes the logarithmic display mode has been used.
Figure E.4 – Example for a phase-resolved PD pattern

© IEC2015
Add, after Annex G, the following new Annex H:
Annex H
(informative)
Evaluation of PD test results during tests with direct voltage

The evaluation of PD test results should be based on records of the apparent charge q of
each individual PD pulse vs. the time at constant DC test voltage level, as shown in
Figure H.1a). It is important to define the time between successive PD pulses where a
resolution time of 2 ms is recommended.
Based on the graph shown in Figure H.1a), the accumulated apparent charge of the individual
pulses vs. the measuring time is displayed in Figure H.1b).
...