Sundstrand Corporation

Jeffery Emmerich

Robert D Ligon

A nonvolatile fail-safe system providing protection from bus fault propagation for a multi-channel electric power generating system includes a controller which provides excitation control and protection for a first generator unit, position control for its generator control breaker (GCB) and position control for a bus tie breaker (BTB); protection logic which generates a trip signal for the BTB when a bus fault is detected isolating the load distribution bus from the tie bus, and thereafter generating an excitation isolation control signal and a GCB trip signal isolating the load distribution bus from the generator unit upon sustained presence of the bus fault. A latching generator control relay is electrically coupled in series with the excitation control and is responsive to the excitation isolation control signal for de-energizing the generator by isolating the excitation control. A circuit monitors the operational status of the controller and generates a breaker fail-safe signal upon sensing operation outside acceptable parameters; and fail-safe logic, responsive to the position status of the generator control relay at the instant of issuance of the breaker fail-safe signal, controls the position of the BTB upon failure of the controller.

Breaker fail-safe system for a multi-channel electric power generating

An analog isolation barrier data acquisition system comprises a plurality of satellite sampling modules which are referenced to remote grounds for sensing direct current (dc) voltages which are referenced to these remote grounds. The satellite sampling modules are capable of monitoring several signals which are referenced to its local ground system, and are comprised of three functional blocks: a signal selection block which allows proper selection of the dc voltage signal to be monitored; a modulation block which modulates the selected dc voltage signal to produce a modulated waveform; and a barrier coupling block which transfers waveform information contained in the modulated waveform from the local floating ground reference system to an analog ground reference system. A central control module, coupled to each of the satellite sampling modules and referenced to the analog ground system, is comprised of three functional blocks: a waveform generation block which generates a basis waveform for use by the modulation blocks; a circuit block which demodulates the modulated waveform information produced by the modulation block of each satellite sampling module; and a master control block for generating control logic signals which are based on information received from the basis waveform generation block.

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Rockford, IL, United States of America

Jeffery Emmerich