Turbine bypass desuperheater control system
First Claim
1. In combination with a steam turbine having a bypass system for diverting excess steam supplied by a steam generator from the turbine and including means for desuperheating the bypassed steam and at least one steam flow control valve, a steam desuperheater control system for controlling the temperature of desuperheated steam, comprising:
- temperature determining means providing a representation of the temperature of the desuperheated steam;
first control means operatively connected to said desuperheating means and responsive to said temperature representation to provide corrective action to said desuperheating means tending to maintain the temperature of the desuperheated steam at a preselected temperature reference value;
steam flow determining means providing a representation of steam flow rate in said bypass subsystem; and
second control means responsive to said steam flow representation and interactive with said first control means to alter said corrective action as a function of steam flow rate in said bypass subsystem.
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Accused Products
Abstract
An adaptive control system for controlling the temperature of desuperheated steam in a turbine bypass system. In one embodiment of the invention, redundant temperature sensors downstream of desuperheating water sprays provide an indication of the actual steam temperature after desuperheating has occurred. The highest value of temperature is automatically selected for control and to provide an error signal to a controller. The controller output, indicative of the deviation from a desired temperature, is multiplied by a factor proportional to steam flow in the bypass system. The multiplied signal is then utilized to proportionally position one or more water control valves to spray more or less water into the bypassed steam. The control system thus automatically adapts itself to variations in steam flow. Preferably, the steam flow is taken as the product of the position of a steam flow throttling valve in the bypass line and the steam supply pressure ahead of the valve. Additionally, operating parameters such as temperature and differential pressures are monitored and continuously compared against limiting values to provide automatic protection action if any of the conditions being monitored warrant such action.
49 Citations
11 Claims
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1. In combination with a steam turbine having a bypass system for diverting excess steam supplied by a steam generator from the turbine and including means for desuperheating the bypassed steam and at least one steam flow control valve, a steam desuperheater control system for controlling the temperature of desuperheated steam, comprising:
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temperature determining means providing a representation of the temperature of the desuperheated steam; first control means operatively connected to said desuperheating means and responsive to said temperature representation to provide corrective action to said desuperheating means tending to maintain the temperature of the desuperheated steam at a preselected temperature reference value; steam flow determining means providing a representation of steam flow rate in said bypass subsystem; and second control means responsive to said steam flow representation and interactive with said first control means to alter said corrective action as a function of steam flow rate in said bypass subsystem. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An adaptive control system for controlling the desuperheating of steam flowing in the steam bypass system of a steam turbine and wherein said bypass system includes a steam flow control valve, said control system comprising:
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spraying means to spray liquid water into said bypass flow of steam to provide desuperheating thereof; means responsive to a control signal to adjust the water flow rate to said spraying means; temperature sensing means downstream of said water spray means providing a temperature signal indicative of the temperature of desuperheated steam; first control means responsive to said temperature signal to produce a corrective signal tending to cause said water flow adjust means to adjust water flow in a manner tending to maintain a preselected temperature of desuperheated steam; steam flow sensing means providing a signal indicative of desuperheated steam flow rate; and second control means responsive to said steam flow rate signal and to said corrective signal to produce said water adjust control signal as the product of said steam flow rate signal and said corrective signal. - View Dependent Claims (10, 11)
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Specification