Patent GB-1085790-A (GB)
Title: Improvements in turbine control system
IPC: F01K7/34
Filed: 1964-11-10
Abstract: 1,085,790. Electric turbine control. GENERAL ELECTRIC CO. Nov.10, 1964 [Nov. 12, 1963], No. 45759/64. Heading G1N. lAlso in Division G3] A system controlling the sharing of load between a "master" turbine and one or more slave turbines comprises means measuring (a) master turbine speed 60, (b) its exhaust pressure 66, (c) its high level extraction pressure 62, and (d) its low level extraction pressure 64; and means interrelating these signals to control, on the master turbine, and on each of the slave turbines, the input pressure valve, and the high and low-pressure extraction valves. The high and low-pressure extraction headers, and the exhaust header may be common to all the turbines and the valves referred to connect the particular turbine to the appropriate header. Master control; inlet valves; The master speed signal, 60, is compared with a reference value set at 107 and the resulting signal combined, 110, with the turbines' exhaust pressure signal from amplifier 128 (derived from transducer 66) to provide a first input to an adder V1, 140. The adder V1 receives a second input signal from amplifier 146 representing the departure of the measured high extraction pressure, 62 from a preset reference value 143, and a third input signal from amplifier 182 representing the departure of the measured low extraction pressure, 64, from a preset reference value 163. The output of V1 controls via servomechanisms 192, 194 the operation of two sets of master input valves. Master control; extraction valves; Further adders V2, 160, and V3, 180 also receive the three input signals (as in (a) above), but with different polarities as determined by inverting amplifiers 144, 146, 164 and 182; and the outputs of V2 and V3 respectively control the master high and low-pressure extraction valves. Slave control; inlet valves; The signal representing the departure of the exhaust pressure (66) from a preset reference 133 is processed and combined separately in adders 14, 14<SP>1</SP>, with reference signals 16, 16<SP>1</SP>, representing the proportion of the total load which slave 1 turbine and slave 2 turbine respectively are required to carry; the resulting signals being amplified 20, 20<SP>1</SP> and used to control the inlet valves 28, 28<SP>1</SP> of the first and second slave turbines, by pneumatic means. Further potentiometers 18, 18<SP>1</SP> vary the proportion of working changes in the total load which the two slave turbines are required to carry. Slave control; extraction valves; The signal representing the departure of the high extraction pressure, 62, from a reference value 143, is processed and combined separately in adders 32, 32<SP>1</SP>, with preset voltages 34, 34<SP>1</SP>, representing respectively the proportion of the total load which the slaves are required to carry; the output of adders 32, 32' being amplified 38, 38<SP>1</SP> and used to control the high-pressure extraction valves 44, 44' of the first and second slaves, by pneumatic means. Potentiometers 30, 30<SP>1</SP> vary the proportion of working changes in the load which the two slaves are required to carry. The low-pressure extraction valves are similarly controlled from the low-pressure extraction transducer 64.