Mechanical protection system that overruns of hydroelectric set

The utility model provides a mechanical protection system that overruns of hydroelectric set, including the first machinery protection system that overruns, still including the mechanical protection system that overruns of the redundant second of arranging, the mechanical protection system that overruns of second includes first, the second switching-over valves of the mechanical protection device that overruns of second, two cross liquid accuses, the oil inlet that protection device was overrun to second machinery connects the pressure oil sources, the other one side control port to on first, the second switching-over valve of actuator port outflow pressure oil content is exerted pressure, the opposite side oil extraction, the actuator port of first switching-over valve and the oil inlet of second switching-over valve be selfcorresponding the series connection in first machinery overrun protection device's oil inlet and actuator port department respectively, the oil inlet of first switching-over valve connects the pressure oil sources, the actuator port of second switching-over valve acts on the governing valve epicoele, the governing valve cavity of resorption connects the pressure oil sources, the epicoele and the cavity of resorption that make the governing valve are in isobaric state, the control port of first, second switching-over valve is exerted pressure after the side decompression, first, the second switching-over valve work of replacing separately. High, the change of being convenient for of reliability.