Dual processor electric power trip unit
AssigneeSiemens Energy & Automation, Inc.
InventorsMichael A. Kinney, Stephen F. Gillette
Life of this patent
Estimating the term…
Abstract
A low voltage electric power monitoring and circuit breaker system includes two processors. The first processor activates the circuit breaker when an overcurrent condition is detected and the second processor monitors the current sensed by the first processor and activates the circuit breaker for overcurrent conditions which should have caused the first processor to activate the breaker. If a current of this magnitude is detected, the second processor activates the circuit breaker as a backup protection for the first circuit breaker.
Claims18
A circuit breaker system for use with electric power lines which transmit an electric power signal including a current component and a voltage component to a load circuit, comprising:
- a circuit breaker which may be tripped to disconnect the electric power lines from the load circuit;
- first digital controller means, coupled to the electric power lines, for tripping the circuit breaker when the current component of the electric power signal has a magnitude that exceeds a first predetermined value;
- and
- second digital controller means, coupled to said electric power lines in parallel with said first digital controller means, for tripping the circuit breaker in accordance with electronically reconfigurable parameters when the magnitude of the current component of the power signal exceeds a second predetermined value, greater than the first predetermined value.
A circuit breaker system for use with multi-phase electric power lines which transmit an electric power signal including a multi-phase current component and a multi-phase voltage component to a load circuit, comprising::
- a circuit breaker which may be tripped to disconnect the electric power lines from the load circuit;
- first digital controller means, coupled to the electric power lines, for tripping the circuit breaker when at least one phase of the multi-phase the current component of the electric power signal has a magnitude that exceeds a first predetermined value;
- and
- second digital controller means, coupled to the electric power lines in parallel with the first digital controller means, for tripping the circuit breaker in accordance with electronically reconfigurable parameters when one of the phases of the multi-phase current component differs in magnitude by more than a predetermined threshold value from at least one other phase of the multi-phase current component.
A circuit breaker system for use with electric power lines which transmit an electric power signal including a current component and a voltage component to a load circuit, comprising:
- a circuit breaker which may be tripped to disconnect the electric power lines from the load circuit;
- first digital controller means, coupled to the electric power lines, for tripping the circuit breaker when the current component of the electric power signal has a magnitude that exceeds a first predetermined value;
- and
- second digital controller means, coupled to the electric power lines in parallel with the first digital controller means, for tripping the circuit breaker in accordance with electronically reconfigurable parameters when the voltage component of the electric power signal has a magnitude that exceeds a predetermined maximum threshold voltage.
A circuit breaker system for use with electric power lines which transmit an alternating current electric power signal including a current component and a voltage component to a load circuit, wherein the voltage component of the electric power signal is an oscillatory signal, the system comprising:
- a circuit breaker which may be tripped to disconnect the electric power lines from the load circuit;
- first controller means, coupled to the electric power lines, for tripping the circuit breaker when the current component of the electric power signal has a magnitude that exceeds a first predetermined value;
- and
- second controller means, coupled to the electric power lines in parallel with the first controller means, for tripping the circuit breaker when the voltage component of the electric power signal has an oscillatory frequency that exceeds a predetermined maximum threshold frequency.
A circuit breaker system for use with electric power lines which transmit an electric power signal including a current component to a load circuit, comprising:
- a circuit breaker, responsive to a trip signal, to disconnect the electric power lines from the load circuit;
- first digital controller means, coupled to the electric power lines and to the circuit breaker, for generating the trip signal when the current component of the electric power signal has a magnitude that exceeds a predetermined value;
- and
- second digital controller means for monitoring the electric power signal, the second digital controller means comprising:
- means for generating a sampled data digital signal representing the current component of the electric power signal;
- and
- alarm signalling means for producing an alarm signal, in accordance with electronically reconfigurable parameters, at an output terminal of the second digital controller means when the sampled data current signal has a value which is greater than a predetermined maximum current threshold value.
A circuit breaker system for use with electric power lines which transmit an electric power signal including a current component and a voltage component to a load circuit, comprising:
- a circuit breaker which may be tripped to disconnect the electric power lines from the load circuit, said circuit breaker including relay means, responsive to a control signal, for closing the circuit breaker to connect the load circuit to the electric power signal;
- first digital controller means, coupled to the electric power lines, for tripping the circuit breaker when the current component of the electric power signal has a magnitude that exceeds a first predetermined value for a first predetermined time interval;
- and
- second digital controller means, coupled to said electric power lines in parallel with said first digital controller means, for:
- (1) tripping the circuit breaker, in accordance with electronically reconfigurable parameters, when the magnitude of the current component of the power signal exceeds a second predetermined value, greater than the first predetermined value, for a second predetermined time interval, greater than the first predetermined time interval and (2) tripping the circuit breaker when the voltage component of the electric power signal has a magnitude which exceeds a third predetermined value, wherein the second digital controller means includes:
- relay means, responsive to a relay close control signal for generating the control signal to close the circuit breaker;
- and
- communications means responsive to a breaker close command from a remote source to generate the relay close control signal.
Dependencies are inferred from the claim text.