Modern power systems operate on the premise that the load is uncontrollable and that system voltage, frequency and stability are primarily maintained through control of the generation. In this paper, we challenge this premise by proposing a much more active role for intelligent loads specifically related to frequency control and dynamic stability. In modern systems the load is typically only controlled under severe stability conditions via load shedding. Recent research has demonstrated that many loads could cost-effectively become intelligent, allowing for the potential of the loads to more actively participate in system operation and control. The potential benefits of active load control are investigated. Also, reliability and implementation issues are explored. Fundamental analysis and multi-machine system simulation examples are used to demonstrate many of the issues

Power-System Frequency and Stability Control using Decentralized Intelligent Loads

An introduction to load management

This research examines the use of autonomous demand response to provide primary frequency control in an interconnected grid. The work builds on previous studies in several key areas: it uses a large realistic model; it establishes a set of metrics which can be used to assess the effectiveness of autonomous demand response; and it independently adjusts various parameters associated with using autonomous demand response to assess effectiveness and to examine possible threats or vulnerabilities associated with the technology. More than 6,000 simulations of the power system model were conducted during the course of the study. The studies demonstrated that very few conditions associated with autonomous demand response have the potential to degrade reliability, and that the marginal benefit attributable to autonomous demand response is quantifiable and can be used to determine the value of the technology, as compared to traditional means, for providing primary frequency control.

Autonomous demand response for frequency regulation on a large-scale model of an interconnected grid

In Denmark a large load management investigation comprising 500 customers has been carried out. The investigation lasted 1/sup 1///sub 2/ years. The authors describe the basis and the results of the investigation. The results show that multi-rate time-of-day tariffs bring about significant changes of behaviour, particularly with domestic customers, but also significantly with industrial and commercial customers. Over this period, tests with bidirectional communication over the power supply network were made. These showed that this solution is technically possible, if a repeater is placed at intermediate substations.

http://ieeexplore.ieee.org/iel3/1235/5277/00206118.pdf

N. Haase

Papers

The results from a major load management project