Research On Governor Additional H_∞ Control Of Synchro-Generator

It is important to do the research of control method for improving stability of generator. The governor additional control method used on steam turbine and hydro turbine was proposed in the thesis based on the restraining disturbance method of H∞ robust control theory.The fluctuation of active power,( △Pe), is used as the measurable key disturbance for destroying stability of generator. At the same time, the nonlinear problem of generator equation will be avoided when the measurable disturbance is used as a feedback in the controller. By using a special filter to obtain the vibration of the disturbance,( △Pe), the governor additional controller will have nothing to do with the setting output of generator active power.The governor additional H∞ control method, (GAHC), was proposed in the thesis used on steam turbine and hydro turbine. The design of the controller is simple, because the effect of the exciter and the complex relation with system are included in the measurable disturbance. The harmfulness to the generator stability of water hammer effect is overcome by the GAHC with the proper function. The design method of governor additional mixed H∞ control, (GAMHC), was also proposed in the thesis used to restrain the measurable disturbance and the uncertain parameter.The surplus transient energy, (STE), produced during the fault period is used as the quantity index to evaluate the damage degree of generator stability. The effect of GAHC to the generator stability was analyzed in single machine system and multi-machine system. The results of analysis show that STE could be reduced by the GAHC, the STE decrease of controlled generator would be helpful to reduce the coupled disturbance transient energy of other generators in multi-machine system. It is means that GAHC would be harmless to the stability of other generators, when it is used to reduce the STE of local generator.The simulating tests of GAHC used on steam turbine and hydro turbine had been done in single machine system and multi-machine system. The results of simulating tests show that the generator stability could be improved by GAHC, it is harmless to the stability of other generators in multi-machine system. It is helpful to reduce the oscillation of other generators. The harmfulness to the generator stability of water hammer effect is overcome by the GAHC.A device used to regulate speed of rotor and simulate governor system on directcurrent motor was proposed in the thesis based on phase lock loop technology. The model of steam turbine and hydro turbine had been realized in the governor system of simulating generator by the device. The dynamic simulating system used to do the research of governor control had been established by the device.The dynamic simulating tests of GAHC used on steam turbine and hydro turbine had been done with the device. The tests were three phases short circuit, restoring synchronous operation and restraining low frequency oscillation in three-machines system. The results of simulating tests show that the stability of generator is improved by GAHC, GAHC is effective in multi-machine machine system although it was designed by using the parameter of local generator. GAHC is a simple and feasible decentralized control method for improving stability of synchro-generator.