A sensor system includes a sensor network comprising at least one optical fiber having one or more optical sensors. At least one of the optical sensors is arranged to sense vibration of an electrical device and to produce a time variation in light output in response to the vibration. A detector generates an electrical time domain signal in response to the time variation in light output. An analyzer acquires a snapshot frequency component signal which comprises one or more time varying signals of frequency components of the time domain signal over a data acquisition time period. The analyzer detects a condition of the electrical device based on the snapshot frequency component signal.

A sensor system includes a sensor network comprising at least one optical fiber having one or more optical sensors. At least one of the optical sensors is arranged to sense vibration of an electrical device and to produce a time variation in light output in response to the vibration. A detector generates an electrical time domain signal in response to the time variation in light output. An analyzer acquires a snapshot frequency component signal which comprises one or more time varying signals of frequency components of the time domain signal over a data acquisition time period. The analyzer detects a condition of the electrical device based on the snapshot frequency component signal.

A method of estimating future aging of a transformer includes generating probabilistic models of factors that affect effective aging of the transformer, generating probabilistic profiles of the factors that affect effective aging of the transformer based on the probabilistic models, generating expected hot spot profiles from the probabilistic profiles, simulating a plurality of aging scenarios of the transformer based on the expected hot spot profiles and ambient temperature profiles, and estimating future aging of the transformer from the plurality of aging scenarios.

A method of estimating future aging of a transformer includes generating probabilistic models of factors that affect effective aging of the transformer, generating probabilistic profiles of the factors that affect effective aging of the transformer based on the probabilistic models, generating expected hot spot profiles from the probabilistic profiles, simulating a plurality of aging scenarios of the transformer based on the expected hot spot profiles and ambient temperature profiles, and estimating future aging of the transformer from the plurality of aging scenarios.

Detection and protection against electric power generator rotor turn-to-turn faults, rotor multi-point-to-ground faults, and rotor permanent magnet faults is provided herein. A fractional harmonic signal is used to determine the rotor fault condition. The fractional harmonic signal may be a fractional harmonic magnitude of the circulating current of one phase. The fractional harmonic may be a fractional harmonic magnitude of a neutral voltage. A tripping subsystem may issue a trip command based upon detection of a rotor turn-to-turn fault condition.

Detection and protection against electric power generator rotor turn-to-turn faults, rotor multi-point-to-ground faults, and rotor permanent magnet faults is provided herein. A fractional harmonic signal is used to determine the rotor fault condition. The fractional harmonic signal may be a fractional harmonic magnitude of the circulating current of one phase. The fractional harmonic may be a fractional harmonic magnitude of a neutral voltage. A tripping subsystem may issue a trip command based upon detection of a rotor turn-to-turn fault condition.

A characteristic variable represents a thermal load on an electrical device. A first mathematical model determines the characteristic variable for a determination time based on an ambient temperature of the electrical device and a value of a thermal operating parameter of the electrical device. The first mathematical model describes a dependency of thermal operating parameters of the electrical device at a calculation time based on the ambient temperature of the electrical device and on an electrical load factor. The characteristic variable is determined for the determination time as the equivalent electrical load factor of the electrical device, for which the first mathematical model, taking into account the ambient temperature at the determination time, predicts a value of the thermal operating parameter of the electrical device determined for the determination time.

A characteristic variable represents a thermal load on an electrical device. A first mathematical model determines the characteristic variable for a determination time based on an ambient temperature of the electrical device and a value of a thermal operating parameter of the electrical device. The first mathematical model describes a dependency of thermal operating parameters of the electrical device at a calculation time based on the ambient temperature of the electrical device and on an electrical load factor. The characteristic variable is determined for the determination time as the equivalent electrical load factor of the electrical device, for which the first mathematical model, taking into account the ambient temperature at the determination time, predicts a value of the thermal operating parameter of the electrical device determined for the determination time.

The present invention relates to a method for determining a state of a capacitive voltage transformer which, on its primary side, comprises a capacitive voltage divider having a first capacitor and a second capacitor. The first capacitor has a high-voltage connection for connection to a high voltage) and the second capacitor has a ground connection. A first resonant frequency is determined by way of a plurality of first short-circuit impedance measurements at different frequencies on a secondary side of the capacitive voltage transformer while the high-voltage connection is connected to earth. A second resonant frequency is determined by way of a plurality of second short-circuit impedance measurements at different frequencies on the secondary side of the capacitive voltage transformer while the high-voltage connection is open. A capacitance ratio of the capacitive voltage divider is determined on the basis of the first resonant frequency and the second resonant frequency.

The present invention relates to a method for determining a state of a capacitive voltage transformer which, on its primary side, comprises a capacitive voltage divider having a first capacitor and a second capacitor. The first capacitor has a high-voltage connection for connection to a high voltage) and the second capacitor has a ground connection. A first resonant frequency is determined by way of a plurality of first short-circuit impedance measurements at different frequencies on a secondary side of the capacitive voltage transformer while the high-voltage connection is connected to earth. A second resonant frequency is determined by way of a plurality of second short-circuit impedance measurements at different frequencies on the secondary side of the capacitive voltage transformer while the high-voltage connection is open. A capacitance ratio of the capacitive voltage divider is determined on the basis of the first resonant frequency and the second resonant frequency.