Coal mill trip control method under low-load three-coal mill running mode

Abstract

The invention relates to a coal mill trip control method under a low-load three-coal mill running mode. The method comprises the steps that whether coal mill trip happens or not is determined under the low-load three-coal mill running mode; and if coal mill trip happens, judgment is made according to the actual output of a unit and the maximum output of remaining two coal mills, different controlstrategies are taken for unit fuel control, water supply control and steam turbine control, and safe and stable operation of the unit is maintained. Compared with the prior art, the problem of controlover the coal mill trip under the low-load three-coal mill running mode is solved.

Description

technical field [0001] The invention relates to the technical field of thermal automatic control and protection, in particular to a coal mill trip control method under the operation mode of three low-load coal mills of a thermal power unit (hereinafter referred to as the low-load three-mill mode). Background technique [0002] Due to the increasing installed capacity of new energy units, the low-load operation of thermal power generating units has become the norm. As an important auxiliary equipment of the boiler system, the coal mill's operation mode directly affects the safe, stable and economical operation of the unit. At present, considering the safe and stable operation of the unit during the low-load period, four coal mills are still running under low-load conditions. If any coal mill trips, the other three coal mills can quickly increase output to maintain the boiler thermal load. Reduce the impact of coal mill tripping on the safe and stable operation of the unit. ...

AI Technical Summary

Problems solved by technology

In the low-load operation mode of the third mill, if any coal mill trips due to failure, the output of the remaining two coal mills is limited by the maximum coal output of a single unit, so it may not be possible to maintain the normal output of the unit, and the thermal load of the boiler drops suddenly, which seriously affects the stability of the boiler. At the same time, due to the low feed water flow rate of the low-load unit, the speed of the small machine is close to the lower limit, it is difficult to control the feed water flow under the tripping condition of the coal mill, the boiler steam temperature fluctuates greatly, and it is easy to enter wet operation, which affects the safe and stable operation of the unit

Sequential valve steam inlet mode steam turbine unit, in order to maintain the steam pressure of the unit under the coal mill tripping condition, it is prone to serious throttling conditions in which the last two valves of the sequence valve are closed, which affects the safe and stable operation of the steam turbine

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