As the wide application of automatic startup and shutdown control technology in coal-fired units

the control strategy of automatic parallel operation of steam driven pumps gradually draws much attentions. In this paper

the control strategy for automatic parallel operation of steam driven pump and electricity driven pump was optimized then applied in a 630 MW unit successfully. The results show that

in the control strategy the first steam driven pump participating in when the electricity driven pump is running

two rotating speed rising stages are designed before and after the outlet valve of the first steam driven pump is opened

the parameters that may fluctuate due to the change in the first team driven pump's rotating speed are set as the independent variables of the speed rising rate function of the steam driven pump

which makes the whole pump parallel operation process be very steady

the process takes 4 minutes for automatic parallel

with fluctuation of the feed water no more than 10 t/h. In the control strategy the second steam driven pump participating in when the first steam driven pump is running

three PID functional blocks are applied in the control strategy of automatic parallel operation. One PID functional block is used for feedwater control and the other two that apply highly adaptive parameters are used to balance the contribution of two steam driven pumps

which shortens the time without leading to large fluctuation of feed water. It takes about 7 minutes for automatic parallel operation of a steam driven pump to another with fluctuation of feedwater less than 15 t/h.