초록 ▼

An electrohydraulic emergency trip system which automatically shuts off the steam supply to a turbine power plant upon the detection of specific operational contingencies is disclosed. The hydraulic portion of the system includes two pair of combined electrical and hydraulically operated pilot trip

An electrohydraulic emergency trip system which automatically shuts off the steam supply to a turbine power plant upon the detection of specific operational contingencies is disclosed. The hydraulic portion of the system includes two pair of combined electrical and hydraulically operated pilot trip valves that are so arranged that the opening of any one valve of each pair decreases the hydraulic trip pressure to close rapidly the steam inlet valves to the turbine; that an open or closed failure of a single trip valve does not prevent a valid trip or cause an unwarranted trip; and finally that an open failure of one pair of the valves does not result in an unwarranted trip. Each pair of valves is electrically operated from an independent voltage source such that the electrical failure of one source does not cause or prevent an unwarranted turbine trip. The pilot portion of the hydraulic system is so arranged that the electrical operation of either pilot valve portion of each pair operates hydraulically the other pilot portion of that pair. The hydraulic portion of the system is also constructed to be responsive to the operation of the conventional mechanical overspeed mechanism. In one embodiment such mechanism operates from the same fluid pressure source to operate the two pair of valves hydraulically. In another embodiment, a second fluid source is used to operate the conventional diaphragm overspeed trip valves of the overspeed mechanism and in turn the diaphragm valve hydraulically operates the two pair of trip valves. In a modification of this embodiment, the diaphragm valves decreases the trip pressure to close the steam inlet valves without the necessity of operating the trip valves.

대표청구항 ▼

An electro-hydraulic emergency trip system for a turbine power plant to close rapidly the steam inlet valves to the turbine in response to a predetermined contingency, comprising: a plurality of steam inlet valves, an operating mechanism for each steam inlet valve operative to close its associated v

An electro-hydraulic emergency trip system for a turbine power plant to close rapidly the steam inlet valves to the turbine in response to a predetermined contingency, comprising: a plurality of steam inlet valves, an operating mechanism for each steam inlet valve operative to close its associated valve in response to a predetermined decrease of fluid pressure in communication with such operating mechanism, a source of fluid under pressure, a first hydraulic means including a drain connecting operatively the source of fluid under pressure to the operating mechanism of each steam inlet valve to pressurize each operating mechanism sufficiently to render the steam inlet valves controllable to an open position at times when the drain is blocked, first and second trip valve means each having a main portion and a pilot portion, said main portion having a movable member to block the flow of fluid through the valve at times when the main member is subjected at one side to a predetermined fluid pressure, said pilot portion having a movable pilot member electrically operable to one condition to decrease the fluid pressure at said one side of the movable main member to render such decrease effective to open the valve and electrically operable to another condition to maintain the predetermined fluid pressure, second hydraulic means interconnecting the main portions of the first and second trip valve means to the first hydraulic means in parallel relationship to block the drain of the first hydraulic means at times only when the movable main members of both the first and second trip valve means is subjected to the predetermined fluid pressure, third hydraulic means interconnecting the one side of the main movable members of both first and second trip valve means to the pilot movable members of both the first and second trip valve means between the source of fluid under pressure and the drain to decrease the pressure against the one side of the main movable member of both trip valve means in response to the operation of the pilot movable member of either the first or second trip valve means, and circuit means including a voltage source responsive to the occurrence of a predetermined contingency to operate the electrically movable pilot members of both the first and second valve means to their one condition, whereby the emergency trip system operates to close the steam inlet valves in response to the operation of the main portion of either the first or second trip valve means and said either main portion operates to open its associated trip valve means in response to the electrical operation of the pilot movable members of either the first and second trip valve means.