The invention provides a protection method for preventing refusing action of a small
steam turbine. The protection method comprises the steps that the
control logic of DCS
software is modified, the first reset redundant
signal is firstly added, then the first abnormal intelligent reminding and alarming
signal is added, and finally the
small engine trip logic judgment
signal is added. By means of the method, the
control system logic is improved, so that the problem that a trip First functional block is unreliable is solved, a
protection system with protection and first out separated is provided, the thought of protection design can be suitable for various DCSs, and the reliability of the
protection system can be improved; and the possibility of protection refusing action caused by the situation that the First functional block is halted, logic design is incomplete, operation of operating personnel is lack of
standardization, and logic constraints of hot control maintenance personnel arelack of
standardization can be reduced; it is ensured that protection logic can be automatically triggered when parameters of the small
steam turbine system are abnormal; equipment is linked in emergency; fault losses are reduced to the greatest extent; and it can be ensured that remote manual switching off of the operating personnel can succeed at a time, and the field crisis can be defused in time.