Patent GB-925252-A (GB)
Title: Improvements in or relating to computers for power supply systems
IPC: G06G7/635
Filed: 1959-09-18
Abstract: 925,252. Electric analogue calculating. SIEMENS-SCHUCKERTWERKE A.G. Sept. 18, 1959 [Sept. 19, 1958], No. 31877/59. Addition to 871,617. Class 37. A computer of the kind described in the parent Specification for determining the most economical division of total load among plural (n) power generating units of a supply system to ensure minimum production cost comprises plural function potentiometer assemblies corresponding to the several power units, each assembly comprising a first potentiometer supplying a signal representing total load N i  of a power unit, a second potentiometer supplying a signal representing the incremental cost #K i /#N i  of the unit, and a third potentiometer adapted to multiply an input signal by the total load; each potentiometer being A.C. fed and each assembly being driven by a first servomotor; there being provided a first comparator developing a first error signal representing deviation from a given power value of the sum #N i  of the outputs of the first potentiometers; a # function potentiometer developing a signal representing a specific load/cost factor # driven by a second servomotor controlled by the first error signal to feed each third potentiometer to produce an output signal representing the product N K # ; n resistance assemblies each comprising series-connected resistances of which each is associated with a particular potentiometer assembly with an admittance proportional to a loss factor coefficient B 1K  and supplied with a signal N K #, from the corresponding third potentiometer to produce a current representing B K1 N K # ; means extracting from the output of n each assembly a signal representing # B K1 N K # K=1 and to develop a voltage representing n 2 # B 1K N K # which is summed with the output K=1 of the second potentiometer to a signal repre- #K i  n senting- + 2 # B 1K N K #; and a second #N i  K=1 comparator associated with each power unit potentiometer assembly to produce a second error signal representing which controls the first servomotor of each corresponding assembly; the computer operation solving the equation In Fig. 2, servomotors 10, 20 adjust potentiometer assemblies 11 to 15 and 21 to 25, respectively in accordance with computed values N i  of output powers of corresponding generating units for maximum economy, so that potentiometers 11, 21 produce signals representing respective generating unit costs K i  as functions of N i  for summation to a total cost signal. Potentiometers 13, 23 produce signals #K i #N i / representing respective incremental costs, and potentiometers 14, 15 and 24, 25 are arranged to multiply their input signals by Ni. Potentiometers 15, 25 receive a signal representing computed load/cost factor # to produce outputs representing #N i , which energize a conductance summation matrix 30 introducing coefficients B 1K  to produce signals #B 1K #N K , which are multiplied by 2 at 17, 27 and added to #K i /#N i  signals at 16, 26 to produce signals in opposition to the computed load/cost factor # signal at the inputs of servomotors 10, 20, which run to adjust the potentiometer assemblies to solve the above generalized equation for each servo system. Signals #B 1K #N K  are multiplied by N i  at potentiometers 14, 24 and combined to give a signal representing which is applied to a # dividing potentiometer driven by servomotor 40 to satisfy the generalized equation and derive a network loss signal N v , which is subtractively combined with total power signal #N i  to give a total active load signal N L . Switch 41 in its upper position compares the total power signal #N i  with a signal from source 28 representing the required total power #N i  soil in servomotor 40 which runs to adjust the computed load/cost factor without regard to the network loss N v , and switch 41 in its lower position compares the total active load signal N L  with a required total active load signal N L  soll from 28, so that servomotor 40 readjusts the computed load/cost factor # thereto. In the more detailed system of Fig. 3, servomotors 106, 206 drive respective potentiometeassemblies 101 to 105 and 201 to 205 in accordance with computed N i  to generate signals K i , N i  and #K i /#N L and to effect multiplication by N i . Potentiometers 105, 205 energized by # signals are coupled over centre-tapped secondary transformers 107, 207 and sense changeover switches 107a, 107b and 207a, 207b to conductance summation matrix 300 comprising seriespaired conductances B 11 , B 12 ; B 21 , B 22 ; introducing predetermined co-efficients B 1K  with appropriate signs by interconnection of switches 107a, 207a and 107b, 207b ; the output currents at the junctions of the pairs of conductances being transistor amplified and coupled over transformers 301, 302 to potentiometers 104, 204 with 1 to 1 step-up and also to addition circuits 108, 208 with 2 to 1 step-up where they are combined with incremental cost signals #K i  - from potentiometers 103, 203 and com- #N L  puted load/cost signals X from potentiometer 403. The resultants are respectively applied to servomotors 106, 206 which operate to satisfy equation (1) above for each system. Consequently the outputs of potentiometers 102, 202 and 104, 204 when additively connected in respective pairs develop a #N i  signal over transformer 407 and a signal #N V  given by equation With switch 409 in its lower position, #N i , is compared with a signal representing #N i , soll from potentiometer 408 in comparator 406 to control servomotor 401, which operates to adjust potentiometers 402, 403 to the computed value of # whereby an amplified # signal is applied over 404 to energize potentiometers 105, 205 and comparators 108, 208 while potentiometer 402 and transformer 405 divide the signal #N v  by # to develop a network power loss signal given by equation (2) above. With switch 409 in its upper position, the total generator load signal #N i  is subtractively combined with N V  to give a signal #N L  representing total active power. This is compared in amplifier 406 with a signal for potentiometer 408 representing required active power #N L  soll, and servomotor 401 is operative to adjust potentiometers 402, 403 to an alternative computed value of X. Measuring instrument 110 responsive to the combined outputs of potentiometers 101, 201 over transformers 109, 209 registers a signal representing total generative cost #K i .