The Study On Nonlinear Control For Mulit-machine Power Sysytem

With the power industry forming of large capacity unit, high-parameter and UHVmodel, the power system is entering into automation and information time. The runningenvironment of power system becomes more and more complex. Therefore, how to ensurethe safe operation of the power grid becomes the focus and difficult of researchers.Electric power is the entomic lifeline of a country. The safe and stable operation ofElectric power not only plays an important part in the entomic development of a country,but also maintains its security. As the power system security brings so many problems,thus, how to ensure the power system stability is one of the hot points incurrent powersystem research.This paper summarizes the application of control theory in power system andanalyses the research status of the power system stability. Based on multi-machineexcitation control models and considering the variables and strong coupling characteristicsof the system, passivity combined with back-stepping control schemes which aimed atenhancing power system stability are proposed in this paper. Passivity and stability areclosely related, the system can be passive to maintain its internal stability. The schemeswhich improve system robustness and simplify structure of the controller effectively havewell-defined. The simulation result shows that the validity of the controller.As the problem of parameters uncertainty in multi-machine power system, the paperselects suitable output function via coordinate transformation which could make themulti-machine excitation control models convert into the form of input and output. Anindirect adaptive fuzzy distribute H∞tracking control scheme based on fuzzyapproximating is proposed. In this scheme, the fuzzy adaptive system is constructed toapproximate unknown function and the H∞compensator controller is designed toeliminate the external disturbance and the fuzzy approximating error. The simulationresults show that the operation angle of rotor for generator tends to a stable value, andrelative rotate speed and tracking error tend to zero when three phase faults bothrecoverable and unrecoverable occurs in multi-machine power system. On account of solve the economic load dispatch problem in power systems, anoptimization algorithm is proposed in this paper which may increases the diversity ofpopulations, could avoid premature convergence and improve their performance in theoptimizing process. The algorithm using quantum bit encodes the present position of theparticle, searching the optimize position with the quantum revolving gate. To overcomethe problem of trapping into the-local optima, it used the quantum not gate to achieve theposition varieties of the particle. At last, the scheme proved effectively by two examples.