Risk Assessment of Transient Voltage Instability
In emerging deregulated markets，transmission and generation facility owners hope to fully utilize their equipment, thus the commonly used deterministic security criteria is over-conventional. The application of risk assessment is a significant extension. Risk is defined as the product of probability with the cost of consequence. It reflects that element failure is probabilistic rather than deterministic in nature. It also involves uncertainty in initial system state, such as network topology and load level. The theory of risk assessment has been applied to many fields in power system. In previous literatures, risk evaluations of thermal instability, transient instability, oscillatory instability and cascading failures were carried out. For voltage instability, risk of static voltage instability was studied. However, voltage instability is a complex process, in which dynamic characteristics of many elements, such as generators, automatic voltage regulators(AVRs), static var compensators(SVCs) and loads can’t be ignored. Evaluating risk of static voltage instability isn’t sufficient to reflect the whole risk of voltage instability. In this paper, based on the theory of risk assessment, risk index and assessing method of transient voltage instability are presented. Since voltage instability often occurs under severe contingencies, multi-element contingency scenarios are modeled besides single-element contingency ones. Cost of control rather than outage loss is used to evaluate the consequence of voltage instability. Risk assessment of transient voltage instability can be divided into two categories. One is assessing the overall risk of the system under all kinds of contingencies; the other is to discovery the relationship between risk and value of certain parameter. In this paper, risk index and assessing method of two categories are proposed. Factors that affect risk of transient voltage instability are analyzed. The relationship among risk, SVC investment and under-voltage load shedding(UVLS) scheme is studied. Furthermore, a risk based method determining SVC optimal investment is proposed.
Voltage stability Risk assessment SVC Under voltage load shedding(UVLS)
Shanshan Zhao Wuzhi Zhong Dongxia Zhang Yonghua Yin Xiaojun Tang
China Electric Power Research Institute(CEPRI)China
国际会议
桂林
英文
1-14
2009-10-28（万方平台首次上网日期，不代表论文的发表时间）