MILTON M HOBBS
Engineers in Delaware

3979904, Sep 14, 1976

Aug 8, 1974

5/495701

Milton M. Hobbs - Springfield PA

Westinghouse Electric Corporation - Pittsburgh PA

F02C 726, F02C 906, F02C 908, F02C 910

60 3914

A combined cycle power plant includes gas and steam turbines and steam generators and a digital/analog control system. A megawatt load control system varies a fuel control signal to govern a detected power output according to a reference value. The fuel control signal determines the flow rate of fuel to the combustor of a gas turbine-generator that is adapted to use gas and liquid fuels. A flow divider comprises a plurality of gear pumps connected to rotate with a common shaft, and distributes liquid fuel equally to a plurality of nozzles of the combustor, the total liquid fuel flow to the nozzles being related to the shaft speed. The shaft speed is detected and a signal representative of the total liquid fuel flow is generated in response to the detected speed. During fuel transfer a liquid fuel valve is positioned to govern the detected liquid fuel flow according to a desired flow such that the power output that results when both the gas and liquid fuels flow to the combustor is dependent upon the level of the fuel control signal and independent of the relative levels of the gas and liquid fuel flows. Undesirable power output disturbances that typically occur during fuel transfer due to nonlinearities of fuel system components are reduced.

3956883, May 18, 1976

Aug 8, 1974

5/495725

Joel M. Anderson - Ypsilanti MI
Kermit R. Wescott - Wilmington DE
Milton M. Hobbs - Springfield PA
Roy W. Kiscaden - Springfield PA

Westinghouse Electric Corporation - Pittsburgh PA

F02C 726

60 3914

A combined cycle electric power plant includes gas and steam turbines and steam generators and a digital/analog control system. An automatic digital portion of the control system functions with temperature and other detectors to provide temperature limit control for the gas turbines through the fuel valve position controls provided therefor. A blade path temperature reference is generated as a function of combustor shell pressure during the startup and load modes of operation, and during the load mode of operation the blade path temperature reference is further generated with dependence on the actual turbine exhaust temperature. In particular, the turbine blade path temperature is allowed to rise under loading operation until it reaches a limit value defined by a predetermined combustor shell pressure characteristic curve. Thereafter, the blade path temperature reference is permitted to rise to a higher and final limit value which exists when the actual exhaust temperature equals a limit temperature value defined by another combustor shell pressure characteristic curve which is higher than the first curve.

3965674, Jun 29, 1976

Aug 8, 1974

5/495693

Milton M. Hobbs - Springfield PA
Roy Kiscaden - Springfield PA

Westinghouse Electric Corporation - Pittsburgh PA

F02C 762

60 3918B

A combined cycle electric power plant includes gas and steam turbines and steam generators and a digital/analog control system. The control system includes a digital automatic control and an analog backup control which are interfaced to control the gas turbine fuel flow for speed and load control purposes. The backup control includes a speed/load control which functions on a feedforward speed control basis without speed feedback correction and on a feedforward load control basis without load feedback correction. The forward speed/load control channel is subjected to high and low limit action and the fuel reference output is applied to a feedback type fuel control, i. e. a throttle valve positioning control. Limit action is also placed on the forward speed/load control channel by a temperature control, a surge control and an overspeed control.