Abb Schweiz Ag

Alan Majors

Kevin Dowdell

Camilo Lopez

Mark Foltz

Steve Miller

Mark Wieland

Xudong Yang

Steve Lee Miller

Mark Stephen Wieland

A system for controlling a turbine valve is provided. The system includes a hydraulic pilot valve section being moveable in a first direction and a second direction; a main hydraulic valve section being moveable in a first direction to close the turbine valve and a second direction to open the turbine valve; a position demand indicating a desired position of the turbine valve; a first feedback indicating an actual position of the hydraulic pilot valve section; and aa second feedback indicating an actual position of the main hydraulic valve section. The system also includes a pilot valve error; a main valve error; a turbine valve error; and a pilot valve adjustment moving the hydraulic pilot valve section in response to the turbine valve error. The turbine valve error is repeatedly determined and the pilot valve adjustment repeatedly moves the hydraulic pilot valve section to minimize the turbine valve error.

Valve position control

A control system is provided for a turbine valve. The turbine valve has a first coil and a second coil to control or sense movement of a mechanical valve positioner. Two valve positioners are provided with each valve positioner having two drive circuits to drive the first and second coils. Switches are provided such that only one drive circuit is connected to each coil at a time. The control system may also include a hydraulic pilot valve section and a main hydraulic valve section. Feedbacks are used to determine a pilot valve error and a main valve error which are combined to determine a turbine valve error. The turbine valve error is repeatedly determined to minimize the error.

A turbine speed probe diagnostic system is provided. The turbine includes a speed probe and a speed reading circuit. A speed lead connects the speed probe and speed reading circuit together to transmit speed signals from the speed probe to the speed reading circuit. A speed probe diagnostic circuit is also provided for connection to the speed lead. An isolation switch is provided to isolate the speed probe diagnostic circuit during normal operation when the speed reading circuit is receiving speed signals from the speed probe. When no speed signals are being received, the isolation switch closes and the speed probe diagnostic circuit performs a test on the speed probe or speed lead.

Turbine diagnostics

A speed control system and a power load balance detector for a turbine is provided. The speed control system includes a speed wheel with a plurality of teeth. A timer stores a time stamp when each of the teeth passes by a speed probe. A first speed estimate is determined for overspeed protection, and a second speed estimate is determined for operational speed control. The power load balance detector trips or shuts down the turbine when an unbalance is above a first threshold and the speed of the turbine is above a second threshold.

Turbine speed detection and use

A breaker between two electrical circuits is provided that is closed when electrical properties in both of the electrical circuits are matching. Two check circuits are provided for comparing electrical properties of the two electrical circuits. Each of the check circuits sets a corresponding authorization to close the breaker. The breaker is only closed if both check circuits set an authorization to close the circuit.

Growing community of inventors

Pittsburgh, PA, United States of America

Alan Majors