Methods for Arc-Flash Prediction in Medium Voltage and Low Voltage Switchgear

117 Pages·2016·6.66 MB·English

Department of Electrical Engineering and Automation
Methods for Arc-Flash
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+ er DOCTORAL
DOCTORAL s DISSERTATIONS
DISSERTATIONS ity
2016
Aalto University publication series
DOCTORAL DISSERTATIONS 221/2015
Methods for Arc-Flash Prediction in
Medium Voltage and Low Voltage
Switchgear
Ghulam Amjad Hussain
A doctoral dissertation completed for the degree of Doctor of
Science (Technology) to be defended, with the permission of the
Aalto University School of Electrical Engineering, at a public
examination held at the lecture hall S1 of the school on 5th of
February 2016 at 12:00.
Aalto University
School of Electrical Engineering
Electrical Engineering & Automation
Power Systems and High Voltage Engineering
Supervising professor
Prof. Matti Lehtonen

Thesis advisor
Prof. Matti Lehtonen

Preliminary examiners
Professor Charles Kim, Howard University, USA.
Professor Hans Edin, KTH Royal Institute, Sweden.

Opponent
Professor Petr Toman, Brno University of Technology, Brno, Czech Republic
Aalto University publication series
DOCTORAL DISSERTATIONS 221/2015

© Ghulam Amjad Hussain

ISBN 978-952-60-6600-4 (printed)
ISBN 978-952-60-6599-1 (pdf)
ISSN-L 1799-4934
ISSN 1799-4934 (printed)
ISSN 1799-4942 (pdf)
http://urn.fi/URN:ISBN:978-952-60-6599-1

Unigrafia Oy
Helsinki 2015

Finland

Publication orders (printed book):
Espoo, Finland
Abstract
Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi
Author
Ghulam Amjad Hussain
Name of the doctoral dissertation
Methods for Arc-Flash Prediction in Medium Voltage and Low Voltage Switchgear
Publisher School of Electrical Engineering
Unit Electrical Engineering and Automation
Series Aalto University publication series DOCTORAL DISSERTATIONS 221/2015
Field of research Power Systems and High Voltage Engineering
Manuscript submitted 7 September 2015 Date of the defence 5 February 2016
Permission to publish granted (date) 19 November 2015 Language English
Monograph Article dissertation (summary + original articles)
Abstract
Nowadays we are highly dependent on the electricity. It has become a need of daily life
including domestic, commercial, transformational, industrial, health care and
telecommunication purposes. Switchgear forms an integral part of the distribution network in
power system. Hence, the occurrence of an electrical fault in switchgear causes interruption of
electricity to the end users. Being highly dependent on electricity, such unexpected
interruptions are unbearable by the modern society. Arc-flash is the unintentional discharge
of electricity through air which produces very high temperature (19,600 ºC), which is hotter
than the surface of the sun and a force equivalent to being hit by a hand grenade. Occurrence of
an arc-flash in switchgear not only causes interruption of electric supply but damage to the
equipment and personnel working in the vicinity. In the worst cases, damage is extended to the
whole substation, hence maintenance duration can last upto few weeks. In USA alone, five to
ten explosions occur due to arc-flashes every day.
Due to the importance of the matter, arc-flash protection has been highly demanded for last
two decades. Several reactive protection techniques have been introduced in the literature and
some of them were implemented commercially. Continuous monitoring of the equipment and
earlier detection of potential failures can facilitate a more proactive and a comprehensive arc-
flash prevention system. This thesis mainly focuses on the pre-emptive detection of potential
arc-flash in medium voltage (MV) and low voltage (LV) switchgear using online condition
monitoring techniques. Three non-intrusive sensors i.e. D-dot sensor, Rogowski coil and
thermal ionization detector have been designed, implemented and tested in switchgear to
detect partial discharge, low power arcing and hotspots due to bad connections. Assessment of
reliability, sensitivity and operability of the mentioned sensors is done in the laboratory. D-dot
sensor is also tested on-site in operational MV switchgear for partial discharge. An effective de-
noising technique based on discrete wavelet transform (DWT) is presented in this thesis.
Moreover a novel idea for the detection of multiple faults in a panel based on correlation
between the cumulative energy and apparent charge of discharge events is also presented.
Hybrid low cost and non-intrusive solution integrated to the supervisory control and data
acquisition (SCADA) system capable of continuous monitoring of switchgear and indicating
any potential arc faults in switchgear before they lead to severe damage to the equipment and
vicinity will be a breakthrough solution in minimizing arc-flash accidents, emergency
interruptions and saving precious lives.
Keywords Medium voltage, low voltage, switchgear, arc fault, partial discharge, condition
monitoring, non-intrusive sensor
ISBN (printed) 978-952-60-6600-4 ISBN (pdf) 978-952-60-6599-1
ISSN-L 1799-4934 ISSN (printed) 1799-4934 ISSN (pdf) 1799-4942
Location of publisher Helsinki Location of printing Helsinki Year 2015
Pages 236 urn http://urn.fi/URN:ISBN:978-952-60-6599-1

Tiivistelmä
Aalto-yliopisto, PL 11000, 00076 Aalto www.aalto.fi
Tekijä
Ghulam Amjad Hussain
Väitöskirjan nimi
Valokaarivikojen ennakointimenetelmät keski- ja pienjännitekojeistoissa
Julkaisija Sähkötekniikan korkeakoulu
Yksikkö Sähkötekniikan ja automaation laitos
Sarja Aalto University publication series DOCTORAL DISSERTATIONS 221/2015
Tutkimusala Sähköverkot ja suurjännitetekniikka
Käsikirjoituksen pvm 07.09.2015 Väitöspäivä 05.02.2016
Julkaisuluvan myöntämispäivä 19.11.2015 Kieli Englanti
Monografia Yhdistelmäväitöskirja (yhteenveto-osa + erillisartikkelit)
Tiivistelmä
Nykyään olemme riippuvaisia sähköstä. Sitä tarvitaan jokapäiväisessä elämässä
kotitalouksissa, kaupallisessa toiminnassa, liikenteessä, teollisessa toiminnassa,
terveydenhoidossa ja tietoliikenteessä. Kojeistot muodostavat olennaisen osan
sähkönjakeluverkoissa. Sähkötekninen vika kojeistossa aiheuttaa keskeytyksen.
Odottamattomia keskeytyksiä ei juuri suvaita. Vikavalokaari on tahattomasti syntynyt
sähköpurkaus ilmassa, ja se synnyttää hyvin korkean lämpötilan (19600 ˚C), joka on kuumempi
kuin auringon pinta. Valokaari synnyttää myös voimavaikutuksen joka tuhoaa laitteita ja
aiheuttaa vaaran läheisyydessä työskenteleville ihmisille. Pahimmissa tapauksissa
tuhovaikutus ulottuu koko sähköasemaan, jolloin vaikutusten korjaaminen voi kestää useita
viikkoja. Yksin Yhdysvalloissa tapahtuu 5-10 valokaarivikaa joka päivä.
Koska asialla on suuri merkitys, valokaarisuojaukselle on syntynyt suuri kysyntä parin viime
vuosikymmenen aikana. Useita reaktiivisia suojausmenetelmiä on esitelty kirjallisuudessa, ja
joitakin niistä on otettu kaupalliseen käyttöön. Jatkuvatoiminen laitteistojen seuranta ja
vikaantumisten varhainen toteaminen voivat johtaa valokaarivikoja estävään järjestelmään.
Tämä järjestelmä tähtää pääasiassa valokaarivikojen ennaltaehkäisevään havaitsemiseen
keski- ja pienjännitekojeistoissa jatkuvatoimisten monitorointitekniikoiden avulla. Kolme
sensorityyppiä, jotka eivät edellytä suojattaviin laitteisiin tunkeutumista, D-Dot -sensori,
Rogowski-kela ja lämpöionisaatiosensori on suunniteltu, toteutettu ja testattu kojeistossa, jotta
osittaispurkaukset, pienitehoiset valokaaret ja huonoista liitoksista aiheutuvat kuumat pisteet
voidaan havaita. Em. sensorien luotettavuus, herkkyys ja toiminnallisuus on arvioitu
laboratoriossa. D-dot -sensori on testattu myös käytössä olevassa keskijännitekojeistossa.
Työssä on esitetty myös tehokas diskreettiin wavelet-muunnokseen perustuva
mittaussignaalin kohinanpoistotekniikka.
Edullinen, laitteisiin tunkeutumaton hybridiratkaisu, joka voidaan liittää
käytönvalvontajärjestelmään (SCADA) ja joka pystyy jatkuvatoimisesti monitoroimaan
kojeistoa ja indikoimaan kaikki mahdolliset valokaariviat, ennen kuin ne kehittyvät ja johtavat
vakavaan laitteiden ja lähiympäristön vaurioitumiseen, tulee olemaan läpimurto
valokaarionnettomuuksien ja niistä aiheutuvien vikakeskeytysten minimoinnissa ja
ihmishenkien pelastamisessa.
Avainsanat Keskijännite, pienjännite, kytkinkojeisto, valokaarivika, osittaispurkaus,
kunnonvalvonta, ainetta rikkomaton sensori.
ISBN (painettu) 978-952-60-6600-4 ISBN (pdf) 978-952-60-6599-1
ISSN-L 1799-4934 ISSN (painettu) 1799-4934 ISSN (pdf) 1799-4942
Julkaisupaikka Helsinki Painopaikka Helsinki Vuosi 2015
Sivumäärä 236 urn http://urn.fi/URN:ISBN:978-952-60-6599-1

Acknowledgement

All praise to The Almighty Allah, merciful and compassionate for providing me this
opportunity and granting me the capability to complete this doctoral dissertation.
Gratitude needs to be expressed to Prof. Matti Lehtonen for initially involving me in this project
by believing in my abilities and skills. He has always welcomed me for the valuable discussion
and new ideas in developing this thesis and ensuring all the necessary tools required for this
research. I truly thank him a lot for continuous encouragement, endless cooperation and strong
support. I am very grateful to Mr. Lauri Kumpulainen for proposing the need of this research
and arranging initial grants. He has always been open for the discussion and contributing to the
research ideas. I am thankful to Prof. Steffen Grossmann for arranging laboratory test up at TU
Dresden. Special thanks to Mr. John Kay for his valuable contribution in our PCIC-IAS articles.
Aalto University, The Finnish Foundation for Technology Promotion (TES), Finnish Cultural
Foundation, Association for Electrical Safety Promotion (Sähköturvallisuuden edistämiskeskus-
STEK), the Research Foundation of Aalto University and Vamp Oy are greatly acknowledged
for their financial support without which this research would not be possible.
I owe my gratitude to the current and former members of the Power Systems and HV laboratory
of Aalto University. First of all I want to thank Dr. M. Shafiq, Dr. Joni Klüss and Dr. Murtaza
Hashmi for providing initial guidance, technical support and countless ideas to start this
research work. Special thanks to Dr. Petri Hyvönen, Dr. Lauri Kütt and Mr. Tatu Nieminen who
have always been ready to understand, analyze, discuss, and suggest, for the realization and
execution of my proposed ideas in the HV Laboratory. At the same time, I want to thank Mr.
Veli-Matti, Mr. Jouni Mäkinen and Ari Haavisto for their laboratory instrumentation and IT
support.
I want to express my deep sense of gratefulness to all other members of our working group and
my friends who were helpful in various ways. My special thanks to Dr. Nagy Elkalashy, Dr.
John Millar, Mr. M. Humayun, Malik Farhan, Farhan Mahmood, Mehrnaz Farzamfar, Merkebu
Degefa, Mubbashir Ali, Bruno Sousa, Hammad Kabir, Ejaz Ahmed, Muhammad Sharif, Dr.
Usman Sheikh and Zoko Frank who were part of my social network or active discussions
throughout my doctoral research period.
Most importantly, my mother receives my veracious gratitude, who has dedicated her whole life
for me and my siblings and provided unconditional love and care. She has made me what I am
today. I would like to thank my sisters (Mrs. Sughra, Mrs. Kalsoom and Mrs. Sajida), brother-
in-laws and other family members who keep praying for my success. I am very grateful to my
uncle Mr. Khuda Bux Sabri, my teacher Mr. Abdul Rasheed Qureshi and my childhood friends
who have a great influence in building my personality which I possess today.
Ghulam Amjad Hussain
Espoo, Sep 2015

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Dedicated to my Mother
For her unconditional and endless love, sincere prayers and tremendous care.

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