Woodward 505E Digital Control for Steam Turbines

 Applications:

The 505E controller is designed to operate single-extraction and/or admission steam turbines of all sizes and applications. This steam turbine controller includes specifically designed algorithms and logic to start, stop, control, and protect singleextraction and/or admission steam turbines or turboexpanders, driving generators, compressors, pumps, or industrial fans. The 505E control’s unique PID structure makes it ideal for applications where it is required to control steam plant parameters like turbine speed, turbine load, turbine inlet pressure, exhaust header pressure, extraction or admission header pressure, or tieline power. The control’s special PID-to-PID logic allows stable control during normal turbine operation and bumpless control mode transfers during plant upsets, minimizing process over- or undershoot conditions. The 505E controller senses turbine speed via passive or active speed probes and controls the steam turbine through HP and LP actuators connected to the turbine steam valves. The 505E controller senses extraction and or admission pressure via a 4–20 mA transducer and uses a PID through a ratio/limiter function to accurately control extraction and/or admission header pressure, while protecting the turbine from operating outside of its designed operating envelope. The controller uses the specific turbine’s OEM steam map to calculate its valve-to-valve decoupling algorithms and the turbine operating and protection limits.

Description:

The 505E control is packaged in an industrial hardened enclosure designed to be mounted within a system control panel located in a plant control room or next to the turbine. The control’s front panel serves as both a programming station and operator control panel (OCP). This user-friendly front panel allows engineers to access and program the unit to the specific plant’s requirements, and plant operators to easily start/stop the turbine and enable/disable any control mode. Password security is used to protect all unit program mode settings. The unit’s two-line display allows operators to view actual and setpoint values from the same screen, simplifying turbine operation. Turbine interface input and output wiring access is located on the controller’s lower back panel. Unpluggable terminal blocks allow for easy system installation, troubleshooting, and replacement.

Features:

·Critical Speed Avoidance (3 speed bands) 

·Auto Start Sequence (hot & cold starts) 

·Valve Limiter(s)  Security (Program is Password Protected)

·Dual Speed/Load Dynamics  First-Out Indication (Shutdowns) 

·Zero Speed Detection with proximity probe (< 0.5 Hz)

· Peak Speed Indication for overspeed trip 

· Two Programmable Functions Keys on the 505E’s front panel

· Two independent Modbus comm links 

· Remote analog setpoints for Speed/Load, Ext/Adm, Aux, and Cascade

· Program upload/download capability

·Feed-forward decoupling algorithm for compressors