Westinghouse Electric Corporation

Westinghouse Electric Company LLC

Jerzy Gutman

Bruce M Cook

Robert W Thompson, Jr

Simon Lowenfeld

Robert E Hager

James P Doyle

A safety or protection system includes a plurality of divisions of first signals; a plurality of safety or protection subsystems each of which receives a corresponding one of the divisions of first signals and produces a corresponding plurality of second signals therefrom; and a reflective memory subsystem for communicating the second signals between the safety or protection subsystems.

Safety or protection system employing reflective memory and/or diverse

A control system for a trip coil in a switchgear mechanism which controls the supply of power to a process control device and ensures de-energization of the trip coil shortly after the trip coil is energized. A transformer is supplied with power by the switchgear and outputs reduced power to a rectifier which is connected to the trip coil via a trip activation device. The output of the rectifier can be monitored to determine the ability of the control system to activate the trip coil and the condition of the power supplied to the process control device.

Reactor trip control with voltage sensing

In a protection system for a complex process control system which generates three independent actuation signals, the power circuit includes three pairs of switches arranged in three groups connected in series with each other and with a load device and a voltage source. Each group of switches includes two switches selected from different pairs of switches and connected in parallel. The same circuit topography is used for normally energized and normally deenergized loads with normally closed siwtches used with the former and normally open switches used with the latter. For testing the circuit, each group of switches is shunted by a resistor to form a leakage path through the configuration of switches. The impedance of each resistor is several times that of a closed switch such that the leakage current is insufficient to energize the load, but sufficient to be detected by a current detector which measures the current drawn from the voltage source. Actuation of each switch has an observable effect on the detected current, and thus the circuit may be tested by selective actuation of the switches without changing the circuit topography and while maintaining the protection function, all without susceptibility to any single failure. In addition, by monitoring the current continuously, the failure of any switch can be detected at the time it occurs.

Testable voted logic power circuit and method of testing the same

The dynamic logic of each channel of a multichannel protection system for a nuclear power plant provides a trip logic path and a global bypass logic path by which pulse signals from a clock source may be transmitted to a dc-to-dc power converter which energizes the undervoltage coils for a pair of contactors in the reactor trip switchgear. Each of the logic paths is constructed of basic logic units which in turn, each include a toroidal core of rectangular hysteresis loop magnetic material having a control winding which must be energized by a dc current in order for pulses applied to an input winding to appear at an output winding. Blockage of pulses through any one of the serially connected basic logic units in a logic path terminates the flow of pulses to the converter through that logic path. The control windings of corresponding logic units of the trip logic path in each channel are energized by one of a set of redundant sensors which monitor one of a plurality of reactor trip parameters. Dynamic voting logic appropriate for existing conditions is implemented in part by microprocessors in each channel which gather status information from the other channels through isolated, fiber optic, multiplexed data links and provide the switching logic for alternate paths for energization of the individual basic logic unit control windings, so that for instance, coincidence of trip signals from corresponding sensors in at least two out of four unbypassed channels is required to trip the reactor switchgear. Local bypasses provide additional energization paths for the control windings of basic logic units associated with sensors which are out of service or being repaired. Pulses propagate through the basic logic units of the global bypass path when an entire channel is taken out of service for treating or maintenance. Interlocks between logic units in the trip logic and global bypass logic paths permit only one path to deliver pulses to the converter at any given instant.

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Plum Borough, PA, United States of America

Jerzy Gutman