If a steam turbine that is running at full load was to experience a full load trip, it could cause a catastrophic overspeed failure in less than 2 seconds.
Since the late 1960's most steam turbine hydraulic fluid systems have incorporated high pressure hydraulics to control the critical components of the turbine's control and protective systems. The change from low pressure to high pressure hydraulic systems significantly reduced the size of the hydraulic actuators used to position the steam valves. In addition the response time of the valves improved greatly, making overall operation more reliable.
Since the mid 1960's turbine hydraulic fluid systems have been using Fire Resistant Fluid (FRF) to control their turbine inlet valves. It is a known “FACT” that low fluid resistivity adversely affects the internal components of servo valves within the hydraulic fluid system. Root cause analysis studies conducted by numerous agencies have determined that acids, conductive water and ferrous particulates affect the resistivity of fire resistant hydraulic fluid.
Hydraulic and lube oil systems are critical to the safe, reliable operation of nearly all power plants. Steam turbine lubrication systems, generator sealing systems and boiler hydraulic devices are just a few of the many power plant components that rely on hydraulic and lubrication fluids. Insufficient attention to the cleanliness of these fluids can lead to increased component wear and increased operating and maintenance costs.
According to NERCGADS for the category of "turbine trip system", there is a 100% probability of at least one forced outage occurring in the next 12 months (EPRI Turbo X computer software). The" turbine trip system" consists of the electronic relays within the turbine control system, the hydraulic fluid system and the trip valves.