Trip oil is a specialized type of hydraulic oil used in turbine systems to control the emergency shutdown (trip) mechanism. Its primary function is to maintain the operation of critical valves, such as the Emergency Stop Valve (ESV), by overcoming the spring force that keeps the valves closed. When the system needs to trip (in emergencies or for regular shutdowns), the trip oil is drained, causing the oil pressure to drop. This pressure loss allows the spring action to close the valves, cutting off steam or fuel flow, and safely shutting down the turbine to prevent damage or hazards.