Investigation of an Insulator Flashunder in an 150 kV OTL of the Power System of Crete
Abstract
Overhead Transmission Lines (OTLs) are used in Power Systems to carry High Voltage between substations, usually over long distances. Faults in OTLs are bound to happen and thus locating and coping with them is an important aspect of OTL’s operation and maintenance. These faults may be of temporary or permanent nature, with certain types of faults progressing over time from the first category to the second. Local weather may also have a direct effect on the occurrence of faults resulting to puzzling events. A special category, often complex in nature, is insulator faults. Insulators are used in OTLs to support phase conductors while not allowing current to flow through the tower’s body to the ground. Traditional ceramic insulators used materials such as porcelain and glass as insulation, but in the last decades composite insulators with two insulating parts (a glass core/rod and a rubber housing), have also known great use mainly due to their low weight and their capability to withstand pollution. However, they are subjected to certain faults unique to them, such as flashunders. Flashunder is a term commonly used lately to describe faults that are related to the rod/housing interface of composite insulators. Such faults are rather difficult to locate as the electrical discharge does not create an easily visible trace (as in the case of flashovers) or a permanent mechanical fault (as in the case of brittle fractures). Such a fault occurred for the first time in the Transmission System of Crete in 2019 and this paper follows and discusses the incident and the experience gained.
Keywords:
flashunder, overhead, transmission, line, insulator, power, high voltage, permanent, transient, faultDownloads
References
H. H. Farr, Transmission line design manual, United States Departmentof the Interior, 1980
L. L. Grigsby (editor), The electric power engineering handbook: electric power generation, transmission and distribution, CRCPress - Taylor and Francis Group, 2012 DOI: https://doi.org/10.1201/b12056
K. O. Papailiou (editor), Overhead lines, CIGRE Green Books, Springer, 2017 DOI: https://doi.org/10.1007/978-3-319-31747-2
European Network of Transmission System Operators for Electricity, Best protection practices for HV and EHV AC-transmission systems of ENTSO-E Electrical Grids, ENTSO-E, 2018
R. K. Tajput, A textbook of power system engineering, Laxmi Publications, 2006
N. Veerappan, S. R. Krishnamurthy, Power system switchgear and protection, S. Chand Publishing, 2009
CIGRE WG B2.45, Vegetation fire characteristics and the potential impacts on overhead line performance, CIGRE, 2019
H. F. Vosloo, The need for and contents of a life cycle management plan for Eskom transmission line servitudes, MSc Thesis, Rand Afrikaans University, 2004
D. Pylarinos, I. Pellas, “Incorporating open/free GIS and GPS software in power transmission line routine work: the case of Crete and Rhodes”, Engineering, Technology & Applied Science Research, Vol. 7, No. 1, pp. 1316-1322, 2017 DOI: https://doi.org/10.48084/etasr.1182
CIGRE WG 33-04, TF 01, “A review of current knowledge: polluted insulators”, CIGRE, 1998
K. Papailiou, F. Schmuck, Silicone composite insulators: materials, design, applications, Springer, 2013 DOI: https://doi.org/10.1007/978-3-642-15320-4
CIGRE WG B2.21, Assessment of in-service composite insulators by using diagnostic tools, CIGRE, 2013
Electric Power Research Institute, Field guide: visual inspection of polymer insulators, 2006
R. Gorur, “Reviewing modes of insulator failure”, INMR, 2011, available at: http://www.inmr.com/reviewing-modes-of-insulator-failure/
D. Pylarinos, K. Siderakis, E. Koudoumas, E. Thalassinakis, “Polymer insulators and coatings in the Cretan power system. the transmission line case”, 9th Mediterranean Conference on Power Generation, Transmission Distribution and Energy Conversion, Athens, Greece, 2-5 November, 2014
S. Gubanski, “Greek power company evaluates alternatives to combat pollution in transmission system on Crete”, INMR, Vol. 10, No. 4, 2002
INMR, “Greek utility battles pollution affecting island transmission system”, INMR, Vol. 15, No. 4, pp. 24-38, 2007
A. Sykaras, V. Rajini, M. G. Danikas, R. Sarathi, “A study of SiR/EPDM mixtures for outdoor insulators”, Engineering, Technology & Applied Science Research, Vol. 7, No. 4, pp. 1737-1740, 2017 DOI: https://doi.org/10.48084/etasr.1251
CIGRE WG B2.21, Guide for the assessment of composite insulators in the laboratory after their removal from service, CIGRE, 2011
K. Lagouvardos, V. Kotroni, A. Bezes, I. Koletsis, T. Kopania, S. Lykoudis, N. Mazarakis, K. Papagiannaki, S. Vougioukas, “The automatic weather stations NOANN network of the National Observatory of Athens: operation and database”, Geoscience Data Journal, Vol. 4, No. 1, pp. 4-16, 2017 DOI: https://doi.org/10.1002/gdj3.44
Database of Weather Stations of the National Observatory of Athens, available at: http://meteosearch.meteo.gr/
T. Stamatakis, “Statistical analysis of faults on 150 kV transmission lines of the power system of Crete”, Degree Thesis, Electrical Engineering Department, Technological Educational Institute of Crete, 2014 (in Greek)
N. Mavrikakis, K. Siderakis, P. N. Mikropoulos, N. Katsarakis, “Condition assessment of a field-aged 150 kV HTV SIR suspension insulator following flashover”, ISH 19th International Symposium on High Voltage Engineering, Pilsen, Czech Republic, August, 23–28, 2015
Downloads
How to Cite
License
Authors who publish with this journal agree to the following terms:
- Authors retain the copyright and grant the journal the right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) after its publication in ETASR with an acknowledgement of its initial publication in this journal.
