Steam valves found on most steam turbines employ hydraulic actuators of the Low Pressure or High Pressure type. One of the key elements in upgrading steam turbine controls is the interface to existing steam valves. ICS provides complete actuator system designs, compatible with the control system, and turnkey installation.

ICS provides interfaces to LP hydraulic systems as follows;

Turbines with MHC controls and LP hydraulic actuators

• Pilot actuators to interface to existing LP hydraulic systems
• Upgrade LP hydraulic actuators to HP hydraulic actuators

Turbines with LP hydraulic servomotors

• I/P units interface to LP hydraulic servomotors
• Upgrade LP servomotors to HP hydraulic actuators

Generally, ICS control upgrades interface directly to HP hydraulic systems, with minimal modifications required on servos and position feedback devices. In some cases, existing HP hydraulic systems may be upgraded to improve valve performance.

Pilot actuators
ICS provides a range of Pilot actuators for interface to existing MHC systems common on older GE and Westinghouse design units. This is a relatively inexpensive way to upgrade, since the existing low pressure hydraulic system and valve actuators need not be changed. ICS provides fail safe electro-mechanical and electro-hydraulic proportional pilot actuators for control of LP hydraulic valves.

Hydraulic servomotors
Many European design turbines, including older ABB and Alstom units, employ low pressure hydraulic servomotors for valve controll. ICS provides a range of I/P (current to pressure) units for control of these type of servomotor systems. This is a relatively inexpensive way to upgrade, since the existing low pressure hydraulic servomotors need not be changed.

HP hydraulic upgrades
HP actuators are now common on most new turbines, and many upgrades involve upgrading to HP actuator systems to provides better valve position dynamics and control accuracy. This involves replacing the existing LP hydraulic actuators and providing a new HP hydraulic actuators and hydraulic power unit (HPU).

ICS selected hardware that is industry proven, non-proprietary, to deliver high performance and easy maintenance systems.

ICS also provides a number of upgrade options applicable to any of these systems;

• Add valve stem feedback
• Redundant HPU systems
• Automatic control of Trip & Throttle valves

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