Research On Wide Area Control Of Power System Low Frequency Oscillation Based On WAMS

With the development of power grid interconnection, in order to further optimize the energy structure, improve the economic operation level of the power grid, a large scale of power transmission is an inevitable trend. Along with the development of interconnected power system and new energy, grid structure is becoming more and more complex, randomness and fluctuation of the actual operating conditions of the system are more obvious, and low frequency oscillation in power system is more and more serious. In order to stable operation of the system, study on control measures of low frequency oscillation has important theoretical significance and engineering application value.Appearance of the wide area measurement system provides a new research direction for solving the problem of low frequency oscillation, the low frequency oscillation damping is studied based on wide area measurement system. The main research contents are as followed:(1) In the case of considering the randomness of power network, the online adjustment of the wide area PSS is studied. Analyzed the PID control and fuzzy control their own characteristics, combined with the structural characteristics of wide area PSS, by means of the fuzzy PID control of PSS input signal is modified online processing; according to PID control of the characteristics of the development of the corresponding fuzzy control rules and the randomness of response system operation mode to online inhibitory effect on low frequency oscillation.(2) The design of multi area PSS online coordination of research and design. Based on the modal analysis method for system state equation of high order model order reduction, retention and low frequency oscillations are related to the state variables and reduce the number of order equation of state; the system closed-loop eigenvalues are transferred to a given vertical band through regional pole placement method and the transformation for solving optimization problems, in order to achieve multiple wide area PSS parameters on-line coordination design.(3) The design of the energy storage device for damping controller to suppress low frequency oscillation. Paper based on the theory of modal analysis of the energy storage inhibition mechanism of low frequency oscillation; then in the complex network in reservoir was constructed additional damping controller model, using the residue method selection controller feedback signal, and gives the design method based on phase compensation method of additional damping controller parameters.(4) The scene has occurred in low frequency oscillation, considering the emergency control strategy of small signal stability. On the basis of probabilistic eigenvalue of the damping ratio sensitivity indices. By the method of semi invariants calculated damping ratio of probability distribution, according to the given damping ratio, determine the specific control measures, including adjusting the generator output power and load, the online to inhibit low frequency oscillation.