Research On Related Problems Of Auxiliary Power Of Heat-engine Plant

In heat-engine plant,to ensure more safe and stable operation of generator sets,and efficiently output power,the auxiliary power system became more and more complex,but the equipment of auxiliary power system became more and more in heat-engine plant.With the development of economy,the of demand user for electricity is growing,coal consumption was relatively small,the rate of auxiliary power was low,the coal-fired units of large capacity would be more and more into the electricity market.Therefore,it is necessary to conduct a more thorough and detailed research on the related problems in auxiliary power system of heat-engine plant,ensuring the system to operate safely.In this paper,taking the capacity of 660 MW of generator set as an example,some problems were analyzed and studied in auxiliary power system :(1)To design and research on the main connection mode of auxiliary power system,the load of auxiliary power system is calculated in detail,to research and select the type of the circuit breaker and contactor,to design and research of power supply for high voltage power plant.Research shows: the 10.5-6.3kV two level voltage level connection mode in auxiliary power system is optimal.(2)To use the PSCAD/EMTDC simulation software to simulate the switching process of the auxiliary power system,to simulate the switching transient process of power supply for auxiliary power system(the loss power of working bus and standby power input process).To simulate the large induction motor in the auxiliary power system,and determine the time of failure and the critical input time of standby power,to make the relationship between the two times.(3)To use Matlab/Simulink simulation software to analyze and compare the excitation inrush current.Research shows: when closing angle is zero,selection of resistance in a certain range,the circuit breaker combined brake resistance is better than interpolation resistance.The circuit breaker combined brake resistance is higher than interpolation resistance about the reduction rate of current,the circuit breaker combined brake resistance can be make the peak(4)of the excitation current to the rated stable range in a very short period of time,its decay rate of the current is faster than interpolation resistance,this will make the system more stable earlier.