Study On Voltage Stability Control And Programming Of Dynamic Security Region

In recent years, some big blackouts occurred in many power systems around the world, which have brought tremendous damages. Such catastrophic events were usually caused by power system instability. Finding more fast and effective security monitoring, assessment and control strategies to guarantee power system stability and economic operating has become a hot topic of the academic and industrial studies. In this thesis, we mainly focus on the study of power system voltage stability and online dynamic assessment. Works of this thesis can be separated into two parts: 1) Part 1 is voltage stability study. We present an emergency voltage stability control approach based on power flow tracing. 2) Part 2 is to develop an on-line progam to calculate the system dynamic security region based on intercept method.As the first part, we present an emergency voltage stability control approach based on power flow tracing. In order to find a reasonable control strategy, we must solve the following two problems. The first is to determine the optimal control quantity. e.g. the minimal load shedding and generation tripping. The second is to determine the optimal control location. In our proposed approach, we determine the minimal load shedding and generation tripping by increasing the impedance of the faulted transmission lines. And, then a bi-direction power flow tracing method is used to locate the load shedding and generation tripping. The approach can reasonablely consider the influence of the nonlinear components existing in power systems, such as OLTC and hard-limit of the exciter. It can also guarantee the load shedding and the generation tripping are minimal. Moreover, since the power flow tracing is the base of the nodal pricing and loss allocation under deregulation environment, our proposed approach can be easily applied to power market environment. Finally, some testing systems, such as New-England 10-generator-39-bus system and IEEE 118-bus system are employed to validate the presented control approach.As the second part, we develop an on-line progam to calculate the dynamic security region (abbr. IPDSR) according to the requirement of the project"dynamic security region and probabilistic security assessment of Henan power system". IPDSR is based on intercept method presented by Tianjin University. As the base of the probabilistic assessment, the calculating speed of IPDSR is very fast and its error is very little. The IPDSR program has been tested by some real power systems and on...