GB827242A - Control systems for electrical generating units - Google Patents

Abstract

827,242. Turbines. LEEDS & NORTHRUP CO. May 16, 1957, No. 15641/57. Class 110(3). [Also in Groups XXXV, XXXVIII and XL (a)] The speed of a turbine 12 driving an electric generator 11 is regulated in accordance with the output (actual or required) of the generator by arranging an electrical control system (see Group XXXVIII) to adjust the fuel, air and water supplies to the boiler 13 feeding the generator and the steam valve 67 in the pipe 58 feeding the turbine. The signals are obtained from the actual generator output, the required generator output, the temperature and pressure of the vapour entering the turbine and the oxygen content of the flue gases. These are combined in various ways to actuate a motor 77 which adjusts the setting of the speed governor 68 and the steam valve 67, as well as the air intake 57, the fuel input 85 and the water supply 37. The particular method of combining the electrical signals is stated to ensure efficient action of the turbine under changing lead conditions, e.g. by using the stored energy of the steam in the boiler to meet a sudden increase in load. The boiler described has little heat storage but the control system is equally applicable to those which possess such storage in the form of heat drums, and also to nuclear power plant. The system can be modified to deal with solid fuel, to maintain the transition from water to steam in a particular zone of the boiler, and to control such auxiliary equipment as flue-gas by-pass and recirculating dampers, tilting burners and desuperheating spray-water valves. Further refinements include electrical circuits for ensuring that when an increased output is called for when the steam pressure is already high the output is met mainly by opening valve 67 and to a lesser extent by increasing the fuel supply.