Measurement of analog coil voltage and coil current
AssigneeGeneral Electric Company
InventorsDale Finney, Adil Jaffer, Zhihong Mao, William Premerlani, Mark Adamiak
Life of this patent
Estimating the term…
Abstract
The measurement of analog coil voltage and coil current during the energizing of the circuit breaker coil that is connected to the output contact of a protective circuit breaker relay in order to detect an incipient failure of the circuit breaker mechanism.
Claims8
A method to determine a deviation in a time characteristic of a circuit breaker coil within a power system which comprises a coil signature element, the method comprising:
- measuring an analog coil voltage and a coil current of the circuit breaker coil to determine a time characteristic baseline solely for the voltage across the circuit breaker coil and solely for the current flowing through the circuit breaker coil;
- measuring an analog coil voltage and a coil current of the circuit breaker coil over time to determine an ongoing time characteristic solely for the voltage across the circuit breaker coil and solely for the current flowing through the circuit breaker coil and wherein each measuring of the analog coil voltage and the coil current comprises measuring the maximum circuit breaker coil current, the duration of the current flowing through the circuit breaker coil, and the minimum voltage during each coil operation;
- comparing the ongoing time characteristic with the time characteristic baseline to identify any changes from the time characteristic baseline that exceed a predetermined threshold;
- and
- outputting a signal where the changes exceed the predetermined threshold.
A method to determine a deviation in a time characteristic of a circuit breaker coil within a power system which comprises a coil signature element, the method comprising:
- measuring an analog coil voltage and a coil current of the circuit breaker coil to determine a time characteristic baseline solely for the voltage across the circuit breaker coil and solely for the current flowing through the circuit breaker coil;
- measuring an analog coil voltage and a coil current of the circuit breaker coil over time to determine an ongoing time characteristic solely for the voltage across the circuit breaker coil and solely for the current flowing through the circuit breaker coil;
- comparing the ongoing time characteristic with the time characteristic baseline to identify any changes from the time characteristic baseline that exceed a predetermined threshold;
- and
- outputting a signal where the changes exceed the predetermined threshold;
- wherein measuring the analog coil voltage and the coil current of the circuit breaker coil to determine a time characteristic baseline comprises developing waveforms for said circuit breaker by repeatedly measuring voltage, current and power measurements utilizing the mathematical equations:
- V(t)=V(tstart+t)
- I(t)=i(tstart+t)/i(tend)
- P(t)=V(t)×l(t)
- wherein “V” refers to voltage, “I” refers to amperes, “P” refers to power, and “t” ranges from zero to the difference between the ending and the starting time;
- the ending and the starting time being at predetermined amplitudes of current flowing through the circuit breaker coil.
Dependencies are inferred from the claim text.