Analysis And Design For Wide-area Networked Control Of Power System Based On Fuzzy Model

In recent years, with the interconnection of power grid, the scale of power system increases rapidly. Although the capacity of power system and the allocation of energy are improved, the interconnecticn also introduced the low frequency oscdlation phenomenon at week tie-line of systems. Sustained low frequency oscillation brings a challenge ththe stability of the system,and it is very important to suppress the low frequency osdllation of the interval mode in the low frequency oscillation. In order to solve this problem, Widearea Damping Controlkr(WADC) is introduced using thmoth signals which is obtained by Wide-area Measurement System(WAMS),and WADC can damp the low frequency oscillation effectively. In this dissertation, the research on the combination of networked control system(NCS) and wide-area control has certain practical significance. The main researchingworksareasfollows:(1) The background and significance of wide-area damping con扛ol of power system based on wide-area measurement 巧stem(WAMS) is presented. The hardware structure of WAMS is depicthd to analyze the composition of communication delay, then the common methods which are used to deal with delay are simply concluded. In addition,the major retharch questions and methods of NCS is summarized,and the NCS current;research situation in wide-area control of power system is also presented.(2)Under the circumstance that the fixed and random delsiy exits in WAMS,a fuzzy logic wide-area damping controller(FLWADC) with delay compensation based on Mamdani fuzzy model is proposed. At first, the design and simplify procedure of FLAWDC without delsiy compensation(FLWADC-DC) is presented in detail. Then,in order th deal whh delgiy in signal transmission, delay information is added ththe FLWADC as another input and as a result a FLWADC-DC is redesigned. At lastj case studies are carried out in MATLAB/SimPowerSystem and approximate Network environment TrueTime toolbox based on a two-area fbur-machine power system thdemonstrate the effectiveness of the proposed FLWADC-DC.(3) The construction of Takagi-Sugeno(T-S) fuzzy model for power system is studied.The single machine infinite system is used as an example th study T-S fuzzy model construction. During the model construction, firstly, the method in direct feedback linearization is introduced th transform the nonlinear elements in dynamic equilibrium to a new feedback control law which contains the origin control signal. Then a T-S model construction method is used to replace linear independent functions in the dynamic equilibrium. After that T-S fuzzy model construction is completed.(4) A T-S fuzzy wide-area damping controller is designed with considering the existence of random delay and packet loss in WAMS. And the environment noise is also considered during the operation of the system. Firstly, a discrete T-S fuzzy model is obtained from continues T-S fuzzy model with the situation of random delay. As packet loss happens in network, the system is modelled as an asynchronous dynamic system. Then, Lyapunov and Robust Hx theory is used to obtain the sufficient condition for system exponentially stable, and linear matrix inequality (LMI) method is introduced to solve the controller parameter. According to parallel distributed compensation (PDC) method, a T-S fuzzy controller is achieved by fuzzy blending the controllers of subsystems. Finally, the controller is tested on single machine infinite power system model with imitation network environment is constructed using MATLAB/SimPowerSystem and TrueTime toolbox.Finally, a summary has been done for all discussions in the dissertation. The further and more deeply researching works are presented.