General Electric Company

Lawrence J Lane

Rodney A Lawson

Irving A Gibbs

Michael J D'Antonio

George S Chambers

A method and apparatus for enabling the continuous monitoring of the operational state of circuit components includes a scheme for generating a plurality of voltage signals representing neutral-to-line voltages of the system and adding to each of those signals a second signal, each second signal being identical. This addition is done vectorially to yield a modified signal. A representation of the modified signal as acted upon by the circuit to be monitored is compared with a representation of the neutral-to-line voltage signal to yield an output signal representative of the operational state of the circuit components.

Method for monitoring operational condition of circuit components

In a system for stabilizing the operation of an electrical generator connected to a power distribution network, which system includes a power system stabilizer operating through a modulator circuit to control generator oscillations, there is included a scheme for testing the integrity of the power system stabilizer and modulator circuit which involves the application of a test signal having known values to the power system stabilizer. This test signal propagates through the circuitry and the resultant output is demodulated to be compared with a stored representation of the test signal to thus yield outputs representing the gain and phase shift of the power system stabilizer and modulator circuit in combination.

Power system stabilizer system having improved integrity checking scheme

Method and apparatus for monitoring an amplifier

A scheme for stabilizing a synchronous alternating current generator through the excitation control to dampen generator oscillations includes a power system stabilizer responsive to signals representing the generator output voltage and output current to provide an oscillation signal which represents the instantaneous magnitude of the generator oscillations. A modulator means is included which develops a signal, representing the generator voltage with respect to neutral, and this latter signal is multiplied by the oscillation signal to provide a control signal which controls the excitation of the generator.

Method and apparatus for damping oscillations of an ac generator

A shaft voltage suppression circuit is used with electrical motors or generators of the type including a field winding supported by a shaft which is movable within bearings, which motor or generator is supplied by way of relatively positive and negative buses with electrical power from a source including an electrical power conversion bridge having controlled rectifiers and uncontrolled rectifiers. The shaft voltage suppression circuit includes a first series combination of a first resistor and a first capacitor connected between the positive bus and a common voltage. A second series combination of a second resistor and a second capacitor is connected between the negative bus and the same common voltage and a unidirectional current conductor is connected in parallel with the second resistor such that there is established a low resistance path for current to pass from the negative bus to the common voltage.

Shaft voltage suppression circuit

A circuit for the simulation or synthesization of the equivalent voltage of a supply comprised of at least one voltage source and one impedance includes means to develop signals proportional to the instantaneous values of the voltage at the terminals of the supply and to the rate of change, with respect to time, of the current supplied to a load from the supply. The two signals thus developed are appropriately scaled and then combined to provide a simulation of the equivalent voltage of the supply.

Voltage synthesization

A generating system employing a generator having a self-excited field winding the excitation of which is achieved by supplying a bridge circuit with signals which are, respectively, proportional to the generator terminal voltage and the load current further includes means to selectively short-circuit the field winding during each cycle of normal generator operation. The system further includes a feedback path or loop for controlling the time during which the field winding is short-circuited which feedback path develops a control signal by comparing a signal representing the voltage supplied to the bridge circuit with a reference signal to develop an error signal which is then modified by a further signal proportional to the Thevenin equivalent voltage of the bridge circuit to thus linearize the feedback loop.

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Salem, VA, United States of America

Lawrence J Lane