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Kirby N.M.,General Electric | Marken P.E.,General Electric | Paradis M.,ATCO Electric | Wang P.,Manitoba Hydro | And 5 more authors.
IEEE Power and Energy Magazine | Year: 2016

High-Voltage (HV) DC transmission and flexible ac transmission systems (FACTSs) have been in operation for over 50 years, and in many cases these installations have become an indispensable part of many power networks around the world. With a design life of typically 30 years, some of the original installations have already been, or are presently being, partially refurbished or replaced, while others are in the planning stages for some method of life extension. The strategy adopted for extending the life of an HVdc system depends on many factors, both commercial and technical, and ranges from refurbishment through the replacement of a few components, to replacement of the complete link. Individual installations have their own specific issues, such as increasing levels of maintenance, obsolescence of particular components, or increasing failure and outage rates, which all lead to a real or perceived risk to availability in the near future. © 2016 IEEE. Source


Setreus J.,KTH Royal Institute of Technology | Mansson D.,KTH Royal Institute of Technology | Hilber P.,KTH Royal Institute of Technology | Arnborg S.,Svenska Kraftnat
Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability | Year: 2012

In the long-term and operational planning of the power transmission system (PTS), one challenge is to identify components critical to system reliability. In this paper, the importance of each component for system reliability and vulnerability are quantified for two scenarios in a model of the Great Britain (GB) PTS. The scenarios are: (1) technical failures based on statistical data and (2) sabotage where the attacker has the ability to immobilize two contiguous components. In a novel method approach, the total importance of each component is based on three separate indices that include the system impact on (i) security margin, (ii) load, and (iii) generation. The final result of the GB system screening, including nearly 7000 components and 50 million outage events, is a ranking list indicating the 30 most critical components for each of the two scenarios. The results show that a component ranking that only includes risks of technical failures cannot be used to describe critical sabotage threats. Based on the results, the system operator can perform further and more detailed analysis on a few components and then make the necessary investments to improve the system reliability for equipment failures and strengthen the system vulnerability against sabotage. © IMechE 2012. Source


Sidenvall P.,STRI | Sundin N.,STRI | Gutman I.,STRI | Carlshem L.,Svenska Kraftnat | Kleveborn R.,Kleveborn Consulting
EIC 2014 - Proceedings of the 32nd Electrical Insulation Conference | Year: 2014

Two main criteria for the optimal design of corona/grading rings for composite insulation system include limit of E-field to avoid corona from a metal part and limit E-field to avoid water-induced corona on composite surface. At present only the first criterion is verified by the standard RIV test. This paper presents an innovative laboratory test method that can be used as a verification of the composite insulation system design to avoid water induced corona on the surface. Several approaches of producing water induced corona have been tested and evaluated. Pre-tests were performed on a small test object to optimize the different procedures. Tests were then performed on a full scale 420 kV composite insulator to verify the complete procedure. Different measuring techniques have also been evaluated. 3D calculation of the electric field for all tested structures has also been performed in Comsol software and compared to E-field criteria. Results from these calculations have also been compared with corona inception levels from the different tests and a good correlation was found. The innovative non-standard Water Drop Corona Induced test seems to be the best practical option for further development. © 2014 IEEE. Source


Ericsson G.N.,Svenska Kraftnat
IEEE Transactions on Power Delivery | Year: 2010

The introduction of smart grid solutions imposes that cyber security and power system communication systems must be dealt with extensively. These parts together are essential for proper electricity transmission, where the information infrastructure is critical. The development of communication capabilities, moving power control systems from islands of automation to totally integrated computer environments, have opened up new possibilities and vulnerabilities. Since several power control systems have been procured with openness requirements, cyber security threats become evident. For refurbishment of a SCADA/EMS system, a separation of the operational and administrative computer systems must be obtained. The paper treats cyber security issues, and it highlights access points in a substation. Also, information security domain modeling is treated. Cyber security issues are important for smart grid solutions. Broadband communications open up for smart meters, and the increasing use of wind power requires a smart grid system. © 2010 IEEE. Source


Winter W.,TenneT TSO bv | Elkington K.,Svenska Kraftnat | Bareux G.,French Electricity Transmission Network | Kostevc J.,ELES
IEEE Power and Energy Magazine | Year: 2015

In the future a growing amount of power electronics will lead to a transition of the power system to a structure with very low synchronous generation. Due to large transit power flows and uncertainties, transmission systems are being operated under increasingly stressed conditions and are close to their stability limits. Together with the integration of large amounts of renewable generation with power electronic interfaces and the addition of high-voltage direct current (HVdc) links into the power system, these challenges will necessitate a review of the operation and control of transmission networks. This article will demonstrate the need for R&D performed by network operators and explain a set of challenges, focusing on three main areas: transmission grid operation in a new power system environment, the need to increase overhead line (OHL) utilization, and the impact of reduced inertia on power system frequency. © 2014 IEEE. Source

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