Marcel Didden

Demand Side Management in a competitive European market: who should be responsible for its implementation?

Abstract Demand side management (DSM), more specifically energy efficiency, is standing in the spotlight due to the Kyoto commitments. An additional factor, the liberalization of the electricity markets, causes every country to review its own DSM activities. Especially in Europe, where the directive for opening the electricity market has a direct impact on the current DSM frameworks, governments will have to consider a change in this framework. In order to achieve this, much research has been done in the past years on how to change the DSM framework in a way that the requirements of both liberalization and the Kyoto Protocol will be met. In this paper, we review the current DSM activities and ongoing research from the starting point ‘who should be responsible for implementing DSM’. We conclude that countries have to make explicit choices on how to arrange their DSM activities for the different customers groups. They have to be aware of the fact that some combinations of DSM activities will lead to counter-productive results and therefore inefficiency. This paper also investigates which of these DSM activities fits best in the open market; a critical review of Integrated Resource Planning (IRP) is used as a starting point. We agree with various proponents of IRP that planning towards minimal societal costs is theoretically appropriate, looking from a societal point of view. We also indicate in this paper that the planning process IRP is partly applicable in the open market. But looking at the practical application of IRP in the past, we must conclude that there are better alternatives for achieving energy efficient goals in a liberalized market.

Ride-through of adjustable speed drives during voltage dips

Abstract Adjustable speed drives are reported to be very susceptible to voltage dips. This paper investigates the behaviour of standard induction motor drives in the power range from 2.2 up to 7.5 kW for different types of voltage dips. Voltage tolerance curves are presented and an optimal selection of the under-voltage protection is proposed in order to maintain operation without loss of performance. The opportunities, provided by an active front end and a boost converter, to improve the ride-through of standard drives are investigated and their effect on the voltage tolerance curves is considered.

Choosing the Correct Mitigation Method Against Voltage Dips and Interruptions: A Customer-Based Approach

Voltage dips and interruptions may cause major economic damage, not only can they create considerable loss of production (manufacturing) or data (ICT), there is also loss of market, the loss of client trust, comfort, etc. that incite energy consumers to implement certain forms of protection for their systems. However, the selection of the most cost-effective mitigation method is difficult because of the wide range in available protection devices and the mostly unknown and variable interruption cost. In this paper, the theoretical selection method is compared with the currently used selection methods in industry, showing a discrepancy between theory and practice. Using an alternative selection method, an optimal mitigation method can be found. This paper describes this method and its use by means of a practical example. The case examined is the protection of a 250 kVA installation, sensitive to voltage dips (ICT load). The proposed method makes a cost-benefit analysis of several proposed mitigation solutions resulting in an overview giving the optimal solution for a certain interruption cost interval. It enables to clearly interpret the investment costs and to compare completely different mitigation methods, only using data available to an industrial customer

Bag the sags

This article describes the vulnerability of variable speed drives (VSD) to voltage sags on a theoretical basis. Then, three embedded mitigation methods are addressed in theory which protect textile processes against voltage sags, and practical measurements with a sag generator are shown. The use of embedded solutions such as kinetic buffering and boost convertor or an active front end will increase the voltage sag immunity of the process. Finally, two processes in the textile industry are described, and a brief cost-benefit analysis of the solutions is made. Experiments with a sag generator show that the voltage sag behaviour can be well described by theoretical models.

The optimal selection of mitigation methods against voltage dips and interruptions: a customer-based approach

Voltage dips and interruptions cause major economic damage. Not only do we have to consider potential loss of production, there is also loss of market, the loss of client thrust, comfort,... that make the energy consumers want to implement a certain form of protection for their systems. However, the abundance of available mitigation methods and the, in many cases, unknown interruption cost make the selection of the most cost-effective mitigation method very difficult. This optimal mitigation method cannot be calculated using traditional theoretical economic methods, and is not always obtained by the currently used selection methods in the industry. However, using an alternative selection method, an optimal mitigation method can be found. This paper describes the steps to be taken, to solve the selection problem by means of a practical example. The examined case is a 250 kVA installation with a high sensitivity to voltage dips (pc load), and without a full knowledge of the cost of a process interruption. The proposed method makes a cost-benefit analysis of all possible solutions resulting in an overview that gives the optimal solution for a certain interruption cost. This method makes it possible to clearly interpret the investment costs and to compare completely different mitigation methods, only using data and methods which are available to an industrial customer. As such, this paper is written from a customer point of view.

Embedded solutions to protect textile processes against voltage sags

Variable speed drives (VSD) are reported to be very susceptible to voltage sags. In textile industry processes, such as extrusion and weaving, many synchronised VSDs are installed, reducing the reliability of the processes under voltage sag conditions. This paper evaluates the influence of embedded mitigation methods on the voltage tolerance curves of extrusion and weaving units using theoretical considerations as well as practical measurements. A brief cost-benefit analysis of the installation in these two textile processes is given.

Geographic generalization of limited voltage sag monitoring data

This paper describes a methodology to estimate the annual number of sags to be expected at a low voltage grid connection point, when only sag characteristics of high and medium voltage substations are known. First, the paper describes an algorithm to calculate the sag characteristics at a low voltage busbar from RMS measurements of the feeding medium and high voltage grid. Subsequently, the paper uses a statistical approach to estimate sag statistics at a randomly chosen low voltage connection point by using the sag information from other low voltage grid connection points at which sag meters are installed.