Power system security in the new market environment: future directions

There is no clear end in sight the degree to which power systems may deregulate, and indeed the trend will likely continue world-wide into the foreseeable future. And although lessons are learned about the complexity of market operations through hard experience, such as the events in California, and adjustments are made to the approaches taken to deregulate, some basic features of this new market environment which have strong impacts on the nature of power systems will persist. These features, which often have profound effects on the assessment of power system security, include: a large number of smaller, more geographically dispersed generating plants each contributing to a large number of potential transactions (source to sink movement of power). As the combinations of dispatch patterns grow, the dimension of computational tasks may grow enormously; actual system operating conditions determined largely by economic drivers (such as fuel cost and market forces) which are difficult to predict and model, and which introduce a significant degree of uncertainty both in short term operation and long term planning; an increase in security problems (especially stability problems) due to the lack of coordinated planning and shortage of adequate transmission and other infrastructure enhancements. This situation may be worsened by aging transmission components; an increase in new technologies, such as wind power, FACTS, or hybrid generation types, for which performance assessment experience is limited and which may introduce additional complexity into the prediction of security (effect of wind variation on security for example); economic factors being the main operational drivers implies there is more incentive for maximum utilization of facilities and a trend to more risk-taking; and more interconnections of systems in order to make increased transactions possible. This has lead to some global problems (such as inter-area oscillations) which require very large system models - to be used for security assessment. This paper discussed some future directions in power system security assessment which will be necessary to deal with the challenges presented by the above features of deregulated systems.