EPQU Magazine - Vol 1 Issue 1

Jean-François CHRISTIN, MGE UPS SYSTEMS

UPS manufacturers follow the IT culture, used to deal with modular and versatile equipment. A question then arises : should the power protection be distributed (installed in the rack) or centralized (in an electrical room). A centralized system is faster to implement. It requires a cheaper and smaller area per kW. Rightsizing centralized power from the beginning facilitates "plug-and-play" IT installations. The efficiency is better optimized, centralized UPS having lower losses cooled by cheaper air-conditionning. A centralized UPS provides better reliability and cost / MTBF ratio : a four 25 Watts light bulbs will cost more compared to one 100 Watt light bulb. Human factor is also to consider when it comes to monitoring and maintaining UPS : distributed UPS are typically managed by IT personnel, untrained for this task. A centralized UPS with a 7X24 service adds to uptime far more than it might add to total cost of ownership. The battery also advocates for a centralized UPS: it is the weakest link in any UPS system. A centralized UPS with a single well-monitored battery allows a longer battery life expectancy. When the total costs of ownership is considered, the savings of a centralized UPS installation are considerable.

Johan Driesen, Ronnie Belmans, K.U.Leuven, ESAT-ELECTA, Belgium

In modern distribution grids, more distributed generation technologies emerge. The most far-going implementations are ‘energy islands’ with a high degree of autonomy from the central grid. This paper considers different technological barriers that emerge with increasing penetration of such systems: power quality, control problems, safety issues, environmental aspects, the availability of primary energy resources and economic aspects.

Carlos Veganzones, Sergio Martínez, Francisco Blázquez, Universidad Politécnica de Madrid, Spain

Wind generation peculiarities introduce new uncertainty factors in the operation of electric power systems. This paper tries to clarify this situation, remarking the main effects involved, reviewing the current state of wind generation technologies, and analyzing the solutions that can be applied. It is shown how the capabilities of most current technologies of variable speed wind turbine generation systems can make compatible a suitable operation of the power system with a high level of wind generation penetration.

Chuck C Thomas, Bill Howe, Mark W Stephens, EPRI Solutions & Math H J Bollen, STRI AB, Sweden

Process hardening offers the prospect of solving vexing power quality problems without incurring prohibitive costs and making a huge capital investment. The technique presented in this paper focuses on identifying the specific types of PQ issues that a facility's process is experiencing, identifying the specific elements within the process that are susceptible, and then surgically dealing with those elements either by replacing them with more robust alternatives, or by some how isolating them from the vagaries of the grid.

Davy W. Thielens, Peter T.M. Vaessen, KEMA

If one thing can be said about the energy market, it is that ‘times are changing’. Our present day grid, with its historically defined structure, will also have to change to cope with the new demands of the future. As will be discussed later on, this transformation can head in different directions. Transition is no longer a mere buzzword, but a vital process that needs closely monitored to ensure that it effected as quickly and economically as possible, that it remains under our control, and that it does actually take us towards our long-term goal of realizing the sustainable supply of energy. For the desired transition, key technologies will have to be identified and evaluated. However, the energy market can no longer be divided up along traditional lines. Regulation, market and technology involve the same issues, which therefore require an integrated evaluation.

By adopting an integrated approach, it is possible to draw up a list of key technologies for smooth, managed transition. From this list, a balanced mix of technologies should be defined and tested. Multi-actor business simulation is a useful tool in this regard, enabling the impact of possible measures and technologies to be forecast while taking account of technical, economic and social variables, as well as allowing for the examination of strategies and the identification of appropriate technologies.

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Andreas Sumper, Antoni SUDRIÀ, Joan RULL, Center for Technological Innovation in Static Converters and Drives, Polytechnic University of Catalonia

Monitoring power quality often seems the solution for power quality problems. However, in order to solve power quality problems something more than simple installation of power quality monitors at the site is needed. This article attempts to dissipate any doubts of engineers about organizing a monitor program to solve power quality problems. It can be organized in three programs: an overall power quality program, the power quality survey and the immunization program. In all three programs, monitoring plays a decisive role. Furthermore, an overview of the main monitor features will be given.

Kjell Sand, Helge Seljeseth, Knut Samdal, SINTEF Energy Research, Trondheim

A new Power Quality Directive (PQD) developed by the Norwegian regulator was put into force January 1st 2005. The main purpose of the PQD is to ensure a satisfactory quality of supply in the Norwegian power system and contribute to a socio-economic rational operation, expansion and development of the power system, taking into account public and private interests that are affected. The regulations apply to those who wholly or partially own, operate or use electrical installations or electrical equipments that are connected to the Norwegian power system, and those who are designated as the transmission system operator. The PQD includes new requirements for Power Quality (PQ) documentation, PQ information and PQ service as well as limits for certain voltage quality phenomena. The phenomena dealt with are mainly the same as defined in EN 50160. In the article a comparison with EN 50160 is given, as the PQD goes further than the EN 50160 on some phenomena.

Math H.J. Bollen, Mats Häger, STRI AB, Sweden

This paper presents the three aspects of power quality concerning distributed energy resources (DER). The voltage quality experienced by a DER unit impacts the performance of the unit: bad voltage quality may reduce the life length of the unit and lead to incorrect operation or tripping. The DER unit’s current (the „current quality