Delay-Dependent Stability for Load Frequency Control With Constant and Time-Varying Delays
Delay-Dependent Stability for Load Frequency Control With Constant and Time-Varying Delays
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DOI：
10.1109/tpwrs.2011.2172821
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发表时间：
2012-05
影响因子：
6.6
通讯作者：
Lin Jiang;W. Yao;Qinghua Wu;J. Wen;S. Cheng
中科院分区：
文献类型：
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作者：
Lin Jiang;W. Yao;Qinghua Wu;J. Wen;S. Cheng
负载频率控制（LFC）需要将远程rtu的测量数据传输到控制中心，并将控制中心的控制信号传输到厂侧。传统的专用通信信道存在恒定的时延，而未来开放通信网络的使用将引入时变时延。这些延迟会降低LFC的动态性能，在最坏的情况下，会导致不稳定。允许嵌入控制器的LFC方案保持稳定的最大延迟时间定义为延迟裕度。本文利用基于lyaponuv理论的时滞相关判据和线性矩阵不等式（LMIs）技术研究了LFC方案的时滞相关稳定性。案例研究分别基于安装比例积分（PI）控制器的单区域和多区域LFC方案。研究了LFC方案的PI控制器增益与延迟裕度之间的关系，所得结果可用于调整PI控制器以达到动态性能和延迟裕度之间的折衷。同时考虑了恒定延迟和时变延迟。仿真研究验证了该准则的有效性。
Load frequency control (LFC) requires transmitting measurements from remote RTUs to control center and control signals from the control center to plant side. Constant delays exist in the conventional dedicated communication channels, while the future usage of open communication networks will introduce time-varying delays. Those delays would degrade the dynamic performance of LFC and in the worst case, cause instability. The maximal delay time which allows an LFC scheme embedded with controllers to retain stable is defined as the delay margin. This paper investigates the delay-dependent stability of the LFC scheme by using Lyaponuv-theory based delay-dependent criterion and linear matrix inequalities (LMIs) techniques. Case studies are carried out based on one-area and multi-area LFC schemes installed with proportional-integral (PI) controllers, respectively. Relationship between the gains of PI controller and the delay margin of the LFC scheme are investigated and results obtained can be used to tune the PI controllers to achieve a compromise between the dynamic performance and the delay margin. Both constant and time-varying delays are considered. The effectiveness of the criterion used is verified by simulation studies.