Under the emergency valve closing condition of high-head ship locks,the water delivery valves close slowly under self-weight,which may result in over-filling or over-discharging in multi-stage ship locks or excessive reverse water head in single-stage ship locks.Excessively fast closing,with a high velocity maintained near the fully closed position,may damage the bottom water seal and even cause failure of the hydraulic structure.To address the difficulty in controlling the emergency closing speed of water delivery valves in high-head ship locks under unpowered conditions,this paper analyzes the feasibility of emergency closing under UPS-powered operation and fully unpowered manual operation,designs an emergency system for the unpowered closing of water delivery valves,and verifies its effectiveness through field tests.This system adds a set of poppet-type solenoid directional valves to the hydraulic system of the ship lock valve,connecting the rod and rodless chambers of the valve cylinder to form a differential circuit.A UPS power supply is used to power the valve group.By actuating different numbers of solenoid directional valves,the lowering speed of the valve under self-weight can be adjusted,solving the problem that the existing hydraulic system cannot realize rapid valve closing when the ship lock is completely powered off.Field prototype tests on the ship lock demonstrate that the proposed scheme features high closing reliability and adjustable closing speed.