D.c. modules employed for simulating electric power system for loadflow and transient stability studies

Claim 2

A DC circuit for representing an electric power system load for operation under steady state and transient conditions and comprising a first circuit for generating at least one output current phasor signal corresponding to a first coordinate component of at least the bus to load current from the actual bus to which the load is connected, a second circuit for generating at least one other output current phasor signal corresponding to a second coordinate component of at least the bus to load current from the actual bus to which the load is connected, each of said first and second circuits including means for receiving input phasor voltage signals corresponding to first and second coordinate components of actual bus voltage, and means for representing the load admittance in each of said first and second circuits so as to generate said output current phasor signals with the desired correspondence.

Claim 3

A DC circuit as set forth in claim 1 wherein each of said receiving means of said first and second circuits includes first means for receiving a voltage phasor signal corresponding to one of said coordinate components of actual bus voltage and having an output, and second means for receiving a voltage phasor signal corresponding to the other said coordinate component of actual bus voltage and having an output.

Claim 4

A DC circuit as set forth in claim 2 wherein said first means for receiving a voltage phasor signal corresponding to one of said coordinate components of actual bus voltage and said second means for receiving a voltage phasor signal corresponding to said other coordinate component of actual bus voltage are first and second operational amplifiers, respectively.

Claim 5

A DC circuit as set forth in claim 3 wherein said means for representing at least the load admittance in said first circuit includes a potentiometer corresponding to load conductance and connected to said first operational amplifier to establish the gain thereof, the output of said first operational amplifier being the product of its associated voltage phasor input signal and load conductance, and a potentiometer corresponding to load susceptance connected to said Second operational amplifier to establish the gain thereof, the output of said second operational amplifier being the product of its associated voltage phasor input signal and load susceptance, and said means for representing at least the load admittance in said second circuit includes a potentiometer corresponding to load susceptance connected to said first operational amplifier to establish the gain thereof, the output of said first operational amplifier being the product of its associated voltage phasor input signal and load susceptance, and a potentiometer corresponding to load conductance connected to said second operational amplifier to establish the gain thereof, the output of said second operational amplifier being the product of its associated voltage phasor input signal and load conductance.

Claim 6

A DC circuit as set forth in claim 4 wherein said potentiometers are adjustable for reaching system steady state conditions, the final adjusted value of each upon attainment of said steady state conditions remaining constant under transient conditions.

Claim 7

A DC circuit as set forth in claim 4 wherein means is provided for summing said outputs of said first and second operational amplifiers of said first circuit to provide as an output therefrom said current phasor signal corresponding to one of said coordinate components of bus to load current, and means is provided for comparing said outputs of said first and second operational amplifiers of said second circuit to generate as an output said other coordinate component of bus to load current.

Claim 8

A DC circuit as set forth in claim 6 wherein said comparison means of said second circuit comprises an operational amplifier.

Claim 9

A DC circuit as set forth in claim 6 wherein means is provided for inverting said comparison means output.

Claim 10

A DC circuit as set forth in claim 6 wherein means are provided in each of said first and second circuits for disabling said means for summing and said means for comparing during imposition of a transient fault signal at the load.

Claim 11

A DC circuit as set forth in claim 9 wherein said means for disabling said means for summing and said means for comparing are field effect transistors whose emitter electrodes are disposed to receive fault signals and whose base electrodes connect to said means for summing and said means for comparing in a manner to cause said disabling upon the presence of a transient fault signal at said emitter electrodes.

Claim 12

A DC circuit for representing an electric power system generator for operating at fixed generator terminal voltage magnitude behind transient reactance under steady state and transient conditions and comprising: a. a first circuit for generating at least one output current phasor signal corresponding to a first coordinate component of at least the generation current to the bus to which the generator is connected and including means for receiving and comprising first voltage phasor signals corresponding to first coordinate components of actual generator terminal voltage and actual bus voltage, and means for representing the generator transient reactance so as to generate said first coordinate component output current phasor signal. b. a second circuit for generating at least one other output current phasor signal corresponding to a second coordinate component of at least the generation current to the bus to which the generator is connected and including means for receiving and comparing second voltage phasor signals corresponding to second coordinate components of actual generator terminal voltage and actual bus voltage, and means for representing the generator transient reactance so as to generate said second coordinate component output current phasor signal, c. a third circuit including means for receiving and comparing a generator mechanical power input signal and a generator electrical power input signal, and means for integrating a signal representing the comparison of generator power signals to provide a genErator swing angle output signal corresponding to the angle of the fixed voltage magnitude at the actual generator, d. a fourth circuit including means for receiving said first and second generation current phasor signals and said first and second generator voltage phasor signals and providing said generator electrical power input signal to said third circuit.

Claim 13

A DC circuit for representing an electric power system generator for operating at fixed generator terminal voltage magnitude behind transient reactance under steady state and transient conditions and comprising: a. a first circuit for generating at least one output current phasor signal corresponding to a first coordinate component of at least the generation current to the bus to which the generator is connected and including means for receiving and comprising first voltage phasor signals corresponding to first coordinate components of actual generator terminal voltage and actual bus voltage, and means for representing the generator transient reactance so as to generate said first coordinate component output current phasor signal. b. a second circuit for generating at least one other output current phasor signal corresponding to a second coordinate component of at least the generation current to the bus to which the generator is connected and including means for receiving and comparing second voltage phasor signals corresponding to second coordinate components of actual generator terminal voltage and actual bus voltage, and means for representing the generator transient reactance so as to generate said second coordinate component output current phasor signal, c. a third circuit including means for receiving and comparing a generator mechanical power input signal and a generator electrical power input signal, and means for integrating a signal representing the comparison of generator power signals to provide a genErator swing angle output signal corresponding to the angle of the fixed voltage magnitude at the actual generator, d. a fourth circuit including means for receiving said first and second generation current phasor signals and said first and second generator voltage phasor signals and providing said generator electrical power input signal to said third circuit.

Claim 14

A DC circuit as set forth in claim 11 wherein said receiving means and said integration means comprise operational amplifiers.

Claim 15

A DC circuit as set forth in claim 12 wherein said means for operation of said DC circuit at faster than real time includes a plurality of serial combination of capacitors and field effect transistors connected in parallel across said integration means, the capacitive effect of said capacitors being initiated by a signal at the emitter electrodes of associated field effect transistors.

Claim 16

A DC circuit as set forth in claim 11 wherein means are connected to said third circuit integrating means to operate said DC circuit at faster than real time.

Claim 17

A DC circuit as set forth in claim 11 wherein a damping resistor is connected to said integration means of said third circuit for representing the damping coefficient of the actual generator.

Claim 18

A DC circuit as set forth in claim 11 wherein a resolver circuit is connected to said third circuit for receiving said generator swing angle output signal and producing first and second trigonometric function output signals of said swing angle output signal.

Claim 19

A DC circuit as set forth in claim 16 wherein said first and second trigonometric function output signals are sine and cosine output signals.

Claim 20

A DC circuit as set forth in claim 17 wherein means for receiving said sine output signal and a generator voltage magnitude signal is connected to said first circuit for producing said first coordinate component generator terminal voltage phasor signal, and means for receiving said cosine output signal and a generator voltage magnitude signal is connected to said second circuit for producing said second coordinate component generator terminal voltage phasor signal.

Claim 21

A DC circuit as set forth in claim 11 wherein each of said receiving means of said first and said second circuit is connected to a faulting device for simulating transient conditions on said DC circuit.

Claim 22

A DC circuit as set forth in claim 19 wherein said faulting devices are field effect transistors connected across said receiving means and having emitter electrodes disposed to receive transient fault signals.

Claim 23

A DC circuit as set forth in claim 11 wherein said fourth circuit means for receiving said first and second generation current phasor signals and said first and second generation voltage phasor signals includes at least a pair of multiplier circuits, each having inputs for receiving corresponding coordinate component current and voltage phasor signals, and each generating output signals which are the products of respective input signals, said fourth circuit further including means for receiving and summing said multiplier circuit output signals and generating said generator electrical power input signal to said third circuit.

Claim 24

A DC circuit as set forth in claim 21 wherein said means for summing the outputs of said multiplier circuit is an operational amplifier.