Patent GB-1006332-A (GB)
Title: Arrangements for simulating synchronous generators for testing purposes
IPC: G01R31/34
Filed: 1962-08-23
Abstract: 1,006,332. Computing arrangements. SIEMENS-SCHUCKERTWEBKE A.G. Aug. 23, 1962 [Sept. 2, 1961], No. 32504/62. Heading G4G. [Also in Division G1] A computing apparatus for simulating a synchronous generator driven by a prime mover includes a rotary transformer and an inductor, the reactance of which is proportional to the reactance of the generator, and is constructed to form and add signals representing the individual quantities in the equation representing the generator operating conditions, viz. where Ws represents the synchronous electric angular velocity, W e  represents the actual instantaneous electric angular velocity, # represents the moment of inertia of the moving parts of the generator and prime mover, k represents the damping constant, p represents the number of pairs of poles on the rotor of the synchronous generator, N # , represents the active power yielded by the stator of the synchronous generator (proportional to the product of the terminal voltage output current and power factor), Nm represents the mechanical power supplied by the prime mover to the generator. According to the invention, in such a computing apparatus, a shaft couples the rotary transformer to the movable member of a rotary potentiometer which is connected to a source of unidirectional voltage, and an instrument is connected to receive the voltage tapped from the potentiometer, in order to indicate the magnet wheel angle (the measure of the angular displacement of the poles of the rotor with respect to the poles of the rotating field generated by the stator currents). An embodiment of the computing apparatus includes a rotary transformer 1, simulating the synchronous generator, with its primary side connected to a source of alternating current and its secondary connected to an autotransformer 4, the output from which is taken to terminals n through an inductor 5, whose reactance is proportional to the reactance of the synchronous generator, and a current coil of a datum converter 6. The supply system fed by the generator is simulated by a system (not shown) connected to the terminals n. The datum converter yields a voltage representing the power N w , while a voltage representing the power Nm is set up on the potentiometer 7, so that the voltage between the terminals 6b and the tap 7b represents N w,  - N m . A voltage derived from the tachogenerator 3, representing (W e - W s ) is applied to the potentiometer 9, whose tapping is set in accordance with the factor and is also fed via the differentiating circuit 12 and amplifier 11 to the potentiometer 10. The tapping of this potentiometer is set in accordance with the factor Voltages representing all the terms on the left of the specified equation are thus arranged in series and applied as an input to the amplifier 13, which controls a servomotor 2 which adjusts the phase of the secondary voltage of the rotary transformer 1 until the system balances, i.e. the input to the servo amplifier is zero and thus the specified equation is satisfied. In order to measure the magnet wheel angle of the synchronous generator the shaft of the rotary transformer carries the wiper 14 of a rotary potentiometer 16 supplied from a battery 15. The voltage output from the wiper is applied to the Y deflection plates of an oscillograph 18, a sawtooth voltage being fed to the X plates, so that the magnet wheel oscillations are represented by a curve on the face of the tube.