Research On Dynamic Characteristics And Control Strategy Of Fossil Plant Units In An Isolated Power Grid

When large-scale faults occur in the power network, if predetermined and reasonable splitting measures are worked out to maintain the isolated power grid stable operation ,which can guarantee the important load of the city normal power supply and can contribute to the global electric power network gradual recovery. However, the operation characteristics and the control strategy of the local power plant in the district power network and the setttings of automatic safety devices are formulated based on the operation characteristics of the large power network, it doesn't consider the possible appearance situation of the isolated power grid ,when the situation appears, the local power plants are difficult to support the loads of the isolated power grid. So, it has very important significance to research on the dynamic characteristics and control strategy of fossil plant units to improve the security and the reliability of the power supply of the isolated power grid.The influencing factors of the isolated operation of the fossil plant units are discussed in this paper, the effects of the power system operating mode and the setttings of generator and automatic safety devices on the isolated operation are pointed out,the load control system and the modes of the primary frequency regulation of the fossil plant unit are introduced, the simulation model of the isolated operation is structured, the issues of the settings of the primary frequency regulation and over-speed protect controller which are designed for the large power network may not suitable for the isolated power grid are discussed, whether the generator is in the isolated power grid could be judged by detecting the speed and the acceleration of the geneator, the control strategy for the isolated operation is presented.Assessment method of isolated operation capacity is introduced in this paper,the assessment should be analyzed from the power system operating mode and the setttings of generator and automatic safety devices, the isolated operation capacity of the fossil plant unit in Guangzhou power grid is assessed and some advices are introduced to enhance the capacity.