General Electric Company

Markus A Eggenberger

Jens Kure-Jensen

Edward H Miller

Patrick C Callan

Mark A Davis

An automatic control system enabling comprehensive operation of a reheat steam turbine with sliding or constant pressure boilers. The control system includes an HP control valve for regulating steam flow to the high-pressure turbine according to load and speed demands, an intercept valve for regulating steam flow to the low-pressure turbine and for reheater pressure control, and a bypass flow system for bypassing excess boiler steam during periods of low loading. The bypass system includes a high-pressure bypass sub-system and a low-pressure bypass sub-system, each having a flow control valve and provision for desuperheating the steam. A signal indicative of actual load demand (ALD) and proportional to the product of boiler pressure and main control valve flow demand is produced. From the ALD signal, reference functions are generated to effect control of the bypass valves. The intercept valve is controlled directly by the ALD signal with a regulation factor inversely proportional to the minimum allowable reheat pressure. Coordinated valve control is effected during all principal phases of turbine operation.

Turbine control system for sliding or constant pressure boilers

In a steam turbine, the presence of water slugs can have an adverse effect on certain turbine parts. One particular area of concern is the low-pressure end of the turbine wherein excess moisture is more likely to occur. Another source of moisture is an extraction line interconnecting a turbine stage with a feedwater heater. It is possible for wet steam and/or water slugs to travel from the feedwater heater to the turbine and vice-versa. The present invention provides a monitoring device for a steam conduit which detects the presence of water slugs or wet steam in a steam conduit and will further indicate a reverse direction of flow in the steam conduit.

Moisture detector for steam line

A testable protective system for an operating system is provided with redundant trip components serially connected to redundant lock-out components. The trip components are signalled by fault sensors which monitor critical conditions of the operating system. These trip components produce an output indicative of such conditions, which output is fed to certain actuated devices which may either correct the condition or shut down the operating system until the cause of the problem can be determined and the necessary repairs made. When it is desired to test one of these trip components, the operator activates the corresponding lock-out component and performs the necessary test. The activation of this lock-out component has an effect of making the protective system output signal (the output to the actuated devices to correct the fault or shut the system down) independent of the output of that trip component when it is being tested. Should an operator mistakenly activate both lock-out components at once, the protective system output signal is a function only of the fault sensor input to a first trip component and a driving signal to the protective system. Thus, even if both lock-out components are activated at once, a fault signal to the first trip component will effect a fault output signal from the protective system to the actuated devices.

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Schenectady, NY, United States of America

Markus A Eggenberger