| With the technique development of the power grid,the constructions of extra-high voltage power grid will start rapidly across the aboard,and the safe and stable operation of the power grid becomes very important.Large-scale blackouts happen occasionally around the world,causing enormous economic losses and social impact.After a blackout,power needs to be restored as reliably and quickly as possible,and consequently,dependable and detailed restoration plans are necessary.Black-start is an effective measure to restore the power system when blackout occurs,on which the research work in this dissertation focuses. Key technique of black-start is discussed in detail.The analysis mainly addresses the problems which may happen during black-start of power systems,covering self-excitation,power frequency overvoltage,switching overvolatage,potential problems of the voltage and the frequency during system restoration,the security and stability of small system when instantaneous single-phase earth fault happens,etc. In a regional power grid for example, based on corresponding software,the detailed actual system simulation models of two black-start schemes are established and the simulation calculation is carried out. The analysis of simulation results verifies the feasibility of black-start schemes. The paper introduces the characteristics of microturbine as a black-start power supply during power system black-start. The above experimental experience and results have realistic significance for setting up the salvage programs to the power gird. |
