Department of Electrical Engineering, Cape Peninsula University of Technology
Abstract A review of electrical energy management techniques on the supply side and demand side is presented. The paper suggests that direct load control, interruptible load control, and time of use (TOU) are the main load management techniques used on the supply side (SS). The supply side authorities normally design these techniques and implement them on demand side consumers. Load management (LM) initiated on the demand side leads to valley filling and peak clipping. Power factor correction (PFC) techniques have also been analysed and presented. It has been observed that many power utilities, especially in developing countries, have neither developed nor implemented DSM for their electrical energy management. This paper proposes that the existing PFC techniques should be re-evaluated especially when loads are nonlinear. It also recommends automatic demand control methods to be used on the demand side in order to acquire optimal energy consumption. This would lead to improved reliability of the supply side and thereby reducing environmental degradation. Keywords: electrical energy management, demandside management, maximum demand, power factor correction
ment is higher than supply). • There is a lack of resources (finance, energy) and EEM helps to postpone the construction a new power plant. On the demand side, energy management is used to reduce the cost of purchasing electrical energy and the associated penalties. The techniques used for EEM are aimed at achieving valley filling, peak clipping and strategic conservation of electrical systems. Al-Shakarchi & Abu-Zeid (2002); and Kissock & Eger (2008) presented the techniques used to decrease the need for additional capacity and the costs involved by increased fuel on the supply side. The implementation of the techniques leads to improving off-peak valley-hours and the load factor of the system. The common load management techniques to SS or DS are presented as load shedding and restoring. There are also more exotic means such as power wheeling, the installation of energy efficient processes and equipment, the use of energy storage devices, co-generation, use of renewable energy and reactive power control. Implementation of these techniques has found a steady increase in application and meets demand side management (DSM) objectives. In this paper, we review the techniques used for electrical energy management carried out on the supply and demand side, and recommend the appropriate methods more suitable for industrial applications.
Electrical energy management (EEM) is a topic that has reached specific concern in the twenty- first century due to its contribution to economic development and environmental advancement. It has as a logical outcome and the planning of varieties of initiatives that could be deployed to reduce energy consumption. EEM maybe performed on the supply side (SS) or demand side (DS). On the supply side, EEM is undertaken when: • There is a growing demand (demand require14
2. Electrical energy management: Power supply side
The power supply side executes production and delivery of electric power. It is also responsible for supplying sufficient electric power at the acceptable standards and high level of reliability. The power utility of a vertical integrated system is normally split into four processes namely generation, transmission, distribution and retailing of electric power. Electric power is a non-storable product, (unlike water or other type of energy that the amount col-
Journal of Energy in Southern Africa • Vol 20 No 3 • August 2009
lected at a certain time may be stored for future use) and hence, the amount generated at any instant should not be higher than the amount required by the demand. The generated...