一种广域滑模模糊HVDC附加控制器设计方法

区域间的低频振荡成为限制区域联络线输送功率大小,影响互联电网安全稳定运行的主要因素之一。为了抑制区域间低频振荡问题,提出了基于滑模控制思想的HVDC模糊附加控制器设计方法。控制器采用广域信号作为反馈输入,基于李亚普莫夫稳定性定理由实时的广域信号确定滑模切换面,从而引入滑模控制理论作为模糊推理的依据,针对典型存在区域间振荡模式的系统在不同的工况下分析了该控制器的实用效果。特征值分析表明,在不同的运行工况下,系统区域间阻尼模式的阻尼都得到很大增强。通过非线性仿真的手段,验证了在不同的工作模式下,不同故障时控制器的动态性能,结果表明控制器均能发挥良好的附加阻尼效果。

Novel Fuzzy Sliding Mode Power System Supplementary Controller Design Method

In China there has been an increasing need for transmitting large amounts of power over long distance.This has made the bulk power system more vulnerable to potential contingencies which may lead to transient instability and even cascading outages.This paper presents a novel approach to enhance AC/DC parallel power system stability using a fuzzy controller.The GPS based phasor measurement(PMU) has been adopted to enhance damping to inter-area oscillations.High voltage direct current(HVDC) transmission system can be used as a means of dynamic adjustment in power system due to its fast response characteristics.The global signals of the power system are adopted as the feedback input.The fuzzy controller is based on the main concepts of sliding mode control,and it is applied to high voltage direct current transmission control system to enhance the damping to the power oscillation.The Lyapunov Stability criterion is adopted to secure the stability of the system.The fuzzy controller ensues the consistence performance when undergo operating condition change.Small signal stability analysis and time domain simulation of a two-area,four-machine AC/DC test system is carried out.The analysis results show that the proposed fuzzy sliding mode controller is capable of damping the system's low frequency oscillation and enhancing the AC system's transfer capability over a wide range of operating conditions.In fact the controller is designed without precise knowledge about the system model and parameter,so it's easy to be applied to real power system.