| Modern large-scale coal to oil chemical enterprise has more complicated electrical power system with respect to traditional petrochemical enterprises, large enterprises of electrical system reliability is very high, not only the design of two power supplies, but also the diesel generators or the independent security power from outside the netw ork, when the system is losing power or shaking to maintain the continuous power su pplying of installation, or Secure parking. Complex power system, the switching modeis more than normal, especially abnormal accident switching has a big affect to syste m, and even cause the unit shutdown, the process of continuous operation is disrupted,caused great loss or fire, explosion, damage to equipment. The power load characteri stics of motor factory is most inductive load, The system power loss or shake, idle m otor has characteristics of generator, with the help of this theory, the Theory of using the bus residual voltage coming out. This paper first analyzes the principle of electri cal fast handoff with factory, and leads to the characteristics of the fast switching dev ice by carrying on the simulation analysis, The principle of the fast switching device and the criterion of the fast switching device are deeply analyzed and the theory of t olerance voltage switching is proposed. Based on study of the service power switchingin power plant, and the dual power Separate switching on single bus in factory, dis cussing the BZT switching and logic analysis of fast switching and switching criterion,the system model is built by using simulation software, make the system switching tr ansient analysis method, proved that the mechanism of fast switching device to realizefast switching. Carries on intuitive, microcosmic cognition for the pressure difference,phase difference and frequency difference in the process between the switching of w ork power supply and standby power supply. Put forward the questions of the long ti me delay automatic BZT switch.On the basis of the problem, the scheme of the fast handover of the three sectio n bus is designed, and the feasibility of the simulation is verified by the transient ana lysis. On the basis of the question,this paper put forward a scheme of three bus fast switching with security power, through the modeling and Simulation of transient anal ysis, describes the design of fast cutting program, and further verify the feasibility. Th e design requirements of three power supply automatic switching are higher than dual power supply. Security power supply automatic function when breakdown of power s upply occur is a key problem to guarantee the reliability of the power supply system.Based on background of power system with high load in coal to oil chemical industr y, demand that the power supply system dispose in time when the breakdown of mai n work power supply appear. ensure the standby power supply put into in time to ma ke the system can restore power quickly, and then start the motor reasonably. Frequen cy, voltage and phase angle of the standby power supply can not be real-time trackin g by the traditional BZT switching, easy to cause the investment shock. At the same time, the traditional automatic switching function can not be adapted to the high load switch. Therefore the problem that putting forward the fast switching device to replace the traditional BZT has become the main problem of the research.Finally this paper put on the system switching of losing power or shaking, and h as carried on the analysis of motor restarting. make theoretical analysis of the starting characteristic of motor, put forward the bus voltage drop when the motor restarting, and the capacity of system verification method. Designing scheme of single motor and the way to control motors restarting. |
PDF Full Text Request