The Hollysys T80 is a fully digital electro-hydraulic control (DEH) system designed for small-to-medium steam turbine generator sets and industrial mechanical-drive turbines rated up to 15 MW. Built on a fail-safe and safety self-locking design philosophy, it provides the speed governing, load control, and pressure regulation functions required for turbine start-up, synchronization, grid-connected operation, and island mode. Three hardware variants are available: T80 (single servo channel), T80C (dual servo channel for redundant valve actuation), and T80I (configured for industrial drive applications such as compressors, pumps, and blowers).

How does triple-mode control work?

The T80 offers three primary regulation modes selectable from the operator interface or via remote command. Speed control mode governs turbine RPM during start-up, synchronization with the grid, and island (isolated) operation. Power control mode regulates generator active power output to a fixed or remotely-adjusted megawatt setpoint with primary frequency regulation — the controller automatically adjusts load in response to grid frequency deviations per grid code requirements. Pressure control mode maintains steam extraction or back-pressure at a configured setpoint, supporting sliding pressure operation where the turbine inlet pressure varies with load. The Coordinated Control System (CCS) mode integrates the turbine into plant-wide boiler-turbine coordination schemes via MODBUS communication.

What electro-hydraulic valves can it drive directly?

The ±200 mA servo output channel drives electro-hydraulic converters directly — no external servo amplifier is required for DDV (direct drive valves), VOITH hydraulic converters, CPC servo valves, or REXA electro-hydraulic actuators. This direct-drive architecture reduces cabinet wiring and eliminates a potential failure point between the controller and the hydraulic system. Valve position feedback is accepted as a 4–20 mA signal from the position transmitter on the actuator.

What turbine protection functions are integrated?

The T80 continuously monitors turbine safety parameters and executes protective actions independently of the operator display. An overspeed limit (103% of rated speed) triggers immediate valve closure. Adjustable limits for main steam pressure low, high exhaust pressure, and high load protect the turbine from process-side excursions. All protection actions are hardwired through relay outputs (16 channels) in addition to MODBUS alarm messaging, ensuring that a communication failure cannot disable the safety response. The control unit is available in IP40 (panel-mount) or IP65 (field-mount) enclosures for installation directly at the turbine skid.