Systems and methods for protecting a turbomachine

A trip throttle valve, comprising:

• a trip throttle valve inlet configured to receive a flow of process fluid from a process fluid source;
• a trip throttle valve outlet configured to fluidly communicate with a turbomachine;
• a throttle valve assembly defining a throttle valve chamber in fluid communication with the trip throttle valve inlet and the trip throttle valve outlet, the throttle valve assembly configured to control an amount of the process fluid flowing into the turbomachine, and the throttle valve assembly comprising
• a valve seat disposed within the throttle valve chamber;
• a valve head displaceable in the throttle valve chamber and configured in an open position to allow the process fluid to flow into the turbomachine and in a closed position to seat in the valve seat to prevent the process fluid from flowing into the turbomachine;
• a piston connected to the valve head via a valve stem;
• a biasing member disposed about the valve stem and configured to bias the piston in a first position such that the valve head is seated in the valve seat;
• a hydraulic cylinder configured to receive the piston and a hydraulic fluid therein;
• and
• an actuator assembly fluidly coupled with the hydraulic cylinder, the actuator assembly configured to transfer the hydraulic fluid to and from the hydraulic cylinder via a pressure differential across the piston;
• and
• a trip valve assembly configured to selectively remove hydraulic pressure from the hydraulic cylinder, the trip valve assembly comprising
• a plurality of trip valves fluidly coupled to the hydraulic cylinder via a first flow path and a second flow path, the plurality of trip valves comprising
• a first trip valve and a second trip valve arranged in fluid communication with a first pressure relief valve in the first flow path;
• and
• a third trip valve and a fourth trip valve arranged in fluid communication with a second pressure relief valve in the second flow path, the first flow path and the second flow path being in parallel with one another;
• and
• a plurality of isolation valves fluidly coupled to the hydraulic cylinder via the first flow path and the second flow path, the plurality of isolation valves comprising
• a first isolation valve and a second isolation valve arranged in the first flow path and configured to selectively prevent fluid communication between the first trip valve and the second trip valve and the hydraulic cylinder;
• and
• a third isolation valve and a fourth isolation valve arranged in the second flow path and configured to selectively prevent fluid communication between the third trip valve and the fourth trip valve and the hydraulic cylinder.