| This paper takes a real provincial power grid in our country as the research background,aiming to improve the dynamic stability and running safety of the provincial network,and suppress system low frequency oscillation.The paper is mainly studied from two directions.First of all,the damping controller can be designed and added on FACTS devices.Owing to new installation of a UPFC in the province power grid,at the same time,based on the strong power and voltage control function,and the large number of main control channel of UPFC,the additional damping controller can be designed and installed on the main control channel of UPFC to provide system more damping.Under the environment of MATLAB software,a set of program which is suitable for multi-machine system has been redacted to conduct the damping torque analysis of UPFC installed in the real power grid.Via the damping torque analysis method,when the damping controller is attached to the different control channels of UPFC,how the damping can be transmitted the target mode was researched,including the process of the damping distribution among different units,and the participation degree of every unit to the mode oscillation.Finally,the best installation channel for the damping controller has been selected,namely the channel of controlling AC voltage V,and the results have been compared with the model analysis method to prove its correctness.In addition,power system stabilizers are resigned and installed on the generators to enhance damping of the real power grid in this paper,and a new method to design the stabilizer has been put forward,namely the distributed design method of stabilizer.In the method,the high voltage side busbar voltage angle of the step-up transformer which is located at the generator exit is used as phase reference point and the local model can be established,it doesn’t need to compute the system parameters outside the power plant to design the stabilizer and the local signal is enough,so it can be designed very simply and conveniently,and is suitable to been applied to large scale power grid,first in the MATLAB software environment,this paper takes the single machine infinite bus system as a example,a power system stabilizer is designed by using the theory of distributed design,and the simulation is used to verify the effectiveness of the proposed method.Then in view of the summer peak operation mode of the provincial power grid in 2016,under the environment of the PSD-BPA power system analysis software,five low frequency oscillation modes which exist in the network has been calculated,and distributed design method is used to design the stabilizer.Finally,the damping ratio of oscillation mode has been contrasted before and after the stabilizer is installed in frequency domain,at the same time,nonlinearsimulation in time domain has been conducted to compare the oscillation amplitude before and after the stabilizer.The results of both frequency domain and time domain show that the method of distributed design of stabilizer can improve the dynamic stability of the provincial network,and is suitable for the design and application in large scale power grid. |
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