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WG for Revision of C57.142IEEE Guide to Describe the Occurrence and Mitigation of
Switching Transients Induced by Transformers, Switching
Device, and System Interaction
Jim McBride - Chairman
Xose Lopez-Fernandez – Vice-Chairman
Tom Melle - Secretary
IEEE Transformers Committee Fall 2020
Virtual Meeting
Tuesday, October 20th , 2020
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Early identification of holders of potential Essential Patent Claims is encouraged
Slide #1
Ways to inform IEEE
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Slide #2
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Slide #3
Patent-related information
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Slide #4
Hamid Abdelkamel Xose Lopez-Fernandez Subhas Sarkar
Israel Barrientos Colby Lovins Cihangir Sen
Enrique Betancourt Mark Lowther Masoud Sharifi
William Boettger Nigel Macdonald Michael Sharp
Jeffrey Britton Arnaud Matig Hemchandra Shertukde
Jagdish Burde James McBride Thomas Sizemore
David Caverly Ross McTaggart Steven Snyder
Jorge Cruz Cienfuegos Vinay Mehrotra Sanjib Som
J. Arturo Del Rio Thomas Melle Mike Spurlock
Yamille del Valle Juliano Montanha Craig Stiegemeier
Huan Dinh Aniruddha Narawane Shankar Subramany
Eduardo Garcia Dhiru Patel Babanna Suresh
Monty Goulkhah Harry Pepe Vijay Tendulkar
John Hall Klaus Pointner Kiran Vedante
Kyle Heiden Bertrand Poulin Rogerio Verdolin
Sergio Hernandez Cano Ulf Radbrandt Dharam Vir
Thomas Hirsch Ashley Reagan Sukhdev Walia
Philip Hopkinson Leslie Recksiedler David Walker
Mohammad Iman Afshin Rezaei-Zare Baitun Yang
John John Pierre Riffon Joshua Yun
Akash Joshi Rodrigo Ronchi Waldemar Ziomek
Deepak Kumaria Marnie Roussell
Moonhee Lee Manish Saraf
Weijun Li Amitabh Sarkar
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C57.142 WG - Current Members(69) Quorum (35)
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Investigation of the Interaction between
Substation Transients and Transformers in
HV and EHV Applications IEEE Task Force within Performance Characteristic – IEEE PES Transformers Committee
Contributing Authors: J. McBride (Chair), Member, IEEE, T. Melle (Secretary), Member, IEEE, X. M. Lopez-Fernandez, Senior Member, IEEE, L. Coffeen, Member, IEEE, R. Degeneff, Fellow Member, IEEE, P. Hopkinson, Fellow Member, IEEE, B. Poulin, Member, IEEE, P. Riffon, Member, IEEE, A. Rocha, M. Spurlock, Member, IEEE, L. Wagenaar, Member, IEEE
TF Paper – Early Access
TF – Paper Status
ACCEPTED
Xose Lopez-Fernandez (Thanks)
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Fall 2020 Agenda
Approval of Agenda – Fall 2020
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Approval of Meeting Minutes - Columbus, OH
Fall 2019 Minutes
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WG for Revision of C57.142IEEE Guide to Describe the Occurrence and Mitigation of Switching Transients
Induced by Transformers, Switching Device, and System Interaction
- IEEE Transformers Committee document
- Co-Sponsored by IEEE Switchgear Committee
Jim McBride - Chairman
Xose Lopez-Fernandez – Vice-Chairman
Tom Melle - Secretary
“Liaison Task Force”Dave Caverly – Chairman
Jim McBride – Vice Chairman
Carl Schuetz - Secretary
Update from Switchgear Liaison Task Force
Fall 2020 Meeting (which was held on Oct. 6, 2020)
Unrestricted Oct. 20, 2020
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Switchgear Liaison Task Force: Meeting History
Meeting Transformers Switchgear LTF
2018 Fall Jacksonville, FL: October 16 Kansas City, MO: Oct 14-18Swgr agreement to establish LTF
2019 Spring Anaheim, CA: March 26Burlington, VT: May 1Inaugural LTF Meeting
2019 FallColumbus, OH: Oct 29
San Diego, CA: Oct 9
2020 Spring Charlotte, NC: March 2 cancelled Virtual : May 3-7, 2020
(LTF did not meet)
2020 Fall
Virtual : Oct. 21, 2020
Virtual : Oct. 6, 2020
2021 Spring
April 25-29, 2021
April 18-23 2021
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• Fall 2019 Switchgear Meeting -San Diego:
technical comments were received from some
switchgear experts (Draft 6). These were
partially reviewed in San Diego.
Liaison Task Force Status Update:(since Fall 2019, Columbus)
• Fall 2019 Transformers Meeting – Columbus: some discussion of comments on Draft 6
from Switchgear meeting in San Diego
• No Spring meetings in Trx or Switchgear. New Draft 8 addressing many of the earlier
comments was circulated in advance of Fall Swgr meeting 2 weeks ago.
• Fall 2020 Switchgear Meeting –Virtual: Oct. 6: Further discussions during the meeting
(Draft 8) and subsequent to the meeting leading ultimately to Draft 8B (which has now
been circulated). Key elements to be discussed today.
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• Observation re “the essence” of the comments and Key Discussion Points from
Switchgear:
▪ Original 2010 version of C57.142 focused mainly on:
- internal resonance cases on MV transformers
- excited by sinusoidal excitation from switching, faults etc at
frequencies at or near internal resonance
▪ Our new document up until draft 6 focused on the same – but with inclusion of HV
and EHV
▪ Comments from Switchgear (E. Dullni) proposes additional material on multiple
reignition mechanism of exciting the internal resonance >> Steep Voltage steps or
breakdowns contain a wide range of frequencies and as such will excite the
transformer internal resonance. If oscillations of successive steep voltages line up with
each other this can result in amplification and severe internal resonant voltages.
Liaison Task Force Status Update:(since Fall 2019, Columbus)
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• General Comment:
• in informal discussions, several folks within Switchgear have
commented that they view these “cross-committee”, “cross
fertilization” activities very positively …
Liaison Task Force (LTF) Status Update:
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Questions?
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Draft 8B
Comments
Edgar Dullni #1
Comments
Carl Schuetz
Comments
Dave Caverly
Comments
Edgar Dullni #2
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Dr. Edgar Dullni
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Explanation of amplification of internal resonance (2)
October 19, 2020 IEEE switchgear meeting fall 2019
Slide 19
-0.0112 -0.011 -0.0108 -0.0106-60
-40
-20
0
20
40
60
Time [s]
Voltage [
kV
]
-0.0112 -0.011 -0.0108 -0.0106-60
-40
-20
0
20
40
60
Time [s]
Voltage [
kV
]
20/0.69 kV
900 kVA
Transformer
with taps at 1/2
winding
12 12.2 12.4 12.6 12.8 13
-20
-10
0
10
20
Time [ms]
Voltage [
kV
] H2
H3
Tap12
H1
20 kV/ div
0.2 ms/div
10 kV/ div
0.2 ms/div
Voltage
breakdowns
at H2
Oscillation
at Tap12
Taken from CIGRE paper A3-302 (2014) by E. Dullni, J. Meppelink and L. Liljestrand entitled "Vacuum
circuit breaker, switching interactions with transformers and mitigation means"
Dr. Edgar Dullni – Add to Sections 5 and 6
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Poll Question #1
Changes to Clause 6.4
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Each reignition creates a steep voltage impulse at the terminals of the
transformer which excites a voltage oscillation inside the winding at the
natural frequency of the transformer (see this excitation after application of
a full wave voltage in Fig. 9b). This excited oscillation already implies
some amplification of the internal winding voltage at the center tap the
impact of which should be covered by lightning impulse testing. If a
subsequent re-ignition occurs in phase with this oscillation before it has
damped out, further amplification by a factor of up to two takes place. Since
the repetition rate of such reignitions varies significantly, it is not expected
they produce a steady train of equally spaced pulses. Therefore, not only
amplification will happen but also extinction or damping. Still, there is a
high probability to temporarily generate high over voltage inside the
windings.
6.4 Interruption with repetitive reignition
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Time Domain Frequency Domain
Pulse Response Resonant Frequency
1,300 Hz
Transient and Frequency Response of 345kV Potential Transformer
(200kV/120V)
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H and X Terminal Energization Transients Zoomed
H Input – 160kV 1µS X 2,400 µS
X Response - 20-35kV @ 41kHz Phase to Ground
Distribution Transformer 230 kV / 20kV 60MVA TX
Energization Transients (Zoomed)
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H-X Magnitude Ratio at 41kHz ≈ 2.5:1
Nominal 60 Hz Ratio ≈ 11:1
Distribution Transformer 230 kV / 20kV 60MVA TX
High Voltage to Low Voltage Frequency Transfer
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Disconnect Switch Energization of 230 kV / 20kV 60MVA TX
Consider the frequency content of the entire transient.
If the reignitions create an in phase voltage amplification that could be
damaging, the frequency content will be high near natural resonant
frequency of the transformer.
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Poll Question #2
Delete to Clause 6.6
- Is clause 6.6. necessary after the addition of 6.5 and modification of other clauses? I would rather delete it.
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6.6 Transformer internal voltage response
For the majority of the time, multiple reignitions will pose no problem to the transformer in service. This is because
the TRV produced and the subsequent reignition transients will be neither of a great enough magnitude nor at one of
the natural frequencies of the transformer winding. However, the reason for concern is simply that all complex
electrical equipment possesses impedance versus frequency characteristics which are not linear. In other words, a
voltage of 50% in the center of a winding at 60 Hz is to be anticipated, but at higher frequencies the observed voltage
may be much lower, or (unfortunately), much greater than normal turns ratio voltage. If a transformer (or motor, or
reactor, etc.) were excited by a periodic voltage at one of its natural frequencies, one would expect to see internal
voltages develop within the winding structure much greater than those seen during normal operation (or even factory
tests). As such, these periodic voltages, if near resonance, can produce voltages within the winding structure that
could result in failure of a perfectly sound transformer insulation structure designed to withstand production induced
and impulse voltage tests.
Frequencies above 0.25 MHz have a time to peak (similar to front time) less than one microsecond. When analyzing
the response of a winding at these high frequencies the standard methods used to compute the impulse response of a
winding (full and chopped wave) and the corresponding windings natural frequencies may not produce a correct
result. The model may not have a frequency response high enough to produce accurate results when analyzing the
voltage distribution at these high frequencies. To obtain reliable analytic solutions the model must possess a
frequency response capability in excess of the exciting wave form.
The saving characteristic in most instances is the sharpness or narrowness of the resonance. Unfortunately, with a
statistical switching devices’ dynamic voltage withstand characteristic, the same switching device and transformer
can produce a broad range of frequencies which increases the probability of producing a voltage applied to the
transformer terminals at a frequency close or equal to one of the natural frequencies of the transformer and thus
producing internal over-voltages. Additionally, it is quite possible for the transient voltage to last for many cycles (of
the high frequency), thereby providing time for the voltage to build within the winding. Given these conditions, it is a
very real possibility that a voltage of periodic shape and of modest magnitude could produce dangerously high
internal over voltages.
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Poll Question #3
Changes to Clause 7.2
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Replace Last Paragraph of Clause 7.2
New Verbiage
Edgar Dullni
Nonlinear resistors or metal oxide varistors connected across portions of a
transformer’s winding structure are also a method for dealing with high
internal voltages caused by external oscillatory excitation at one of the
transformers natural frequencies. This can effectively address the concerns at
one frequency and one location within the winding, but should not be
considered as a complete solution for all natural frequencies.
7.2 Other mitigation methods
Last Paragraph
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Poll Question #4
Changes to Example A1
- I have also reviewed the examples. In particular, A1 gives me a lot of headache, since it focusses so much on the internal resonances. In this context it is very speculative I think. The analysis should rather refer to the clauses in the main text than describing the phenomenon with own words. I think example A1 needs a major revision.
Draft 8B
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Poll Question #5
Changes to Example A5
- Example 5 is also not consistent and should be revised. I think with disconnector switching, which is described in this example, only the steepness of the breakdowns and the high number of breakdowns is decisive. Transformer resonances do not play a role.
Draft 8B
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Request / Comment from
Switchgear Committee TF Meeting October 6, 2020
There are very fast re-ignition transients that
occur with reactor switching and sometimes with
transformer switching. It is understood that these
very fast transients are not always covered by
standard factory acceptance tests. The
switchgear committee requestor would like to see
some guidance from the transformer and reactor
manufacturers on some realistic limits for these
high frequency transients. These transients can
also damage the switching devices.
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Membership of TF on Mitigation MethodsPhil Hopkinson – TF Chair
Pierre Riffon – TF Vice-Chair
Akash Joshi – TF Secretary
Don Ayers Changir Sen
Dave Caverly Hamid Sharifnic
Monty Goulkhah Steve Shull
John Hall Thomas Sizemore
Chuck Johnson Mike Spurlock
Jim McBride Rogerio Verdolin
Bertrand Poulin Shekhar Vora
Amitabh Sarkar Loren Wagenaar
Pugal Selvaraj Waldemar Ziomek
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Next Meeting
(April 27, 2021 - Toronto, CA)
Adjournment