Patent ID: 11943236
Assignee: HITACHI ENERGY LTD
Field: Digital communication (Electrical engineering)
Classification: CPC H  G  Y | IPC G  H

Claim 17:
18. A non-transitory machine-readable storage medium comprising a plurality of instructions stored thereon that, in response to being executed, cause a controller to:
determine a plurality of measured values of a first operational parameter of a transformer based upon one or more signals received from one or more sensors of the transformer, the first operational parameter comprising a temperature associated with the transformer;
compare the plurality of measured values to a predetermined threshold value range;
determine, based on the comparison, whether the plurality of measured values have stabilized to a predefined load condition;
determine a second measured value of a second operational parameter of the transformer based upon one or more signals received from the one or more sensors of the transformer;
calculate a first expected value of the first operational parameter in response to a determination that that a first measured value of the plurality of measured values has stabilized to the predefined load condition, wherein the calculating is based on the second measured value of the second operational parameter and a model of the transformer that relates the first and second operational parameters;
compare the first measured value of the first operational parameter to the first expected value of the first operational parameter;
determine a residual value indicative of an effect of noise on a measurement of at least one of the first and second operational parameters of the transformer;
determine whether the residual value is within a predefined upper bound and a predefined lower bound; and
identify that the transformer is subject to a cyber attack when:
a difference between the first measured value and the first expected value exceeds a first threshold, and
the residual value is not within the predefined upper bound and the predefined lower bound;

calculate an expected oil characteristic temperature from at least one of an ambient temperature, an oil temperature from a top of a tank, or an oil temperature from a bottom of the tank;
calculate an expected hot spot characteristic temperature from the at least one of the ambient temperature, the oil temperature from the top of the tank, or the oil temperature from the bottom of the tank;
calculate expected power total loss conditions at the expected hot spot characteristic temperature;
compare an expected power balance and an expected power total loss;
determine whether the difference between the expected power balance and the expected power total loss exceeds a predetermined threshold; and
execute a corrective action in response to a determination that the difference between the expected power balance and the expected power total loss exceed the predetermined threshold to mitigate an effect of the difference between the expected power balance and the expected power total loss, the corrective action comprising at least one of adjusting a tap changer setting of the transformer and deactivating the transformer in response to the determination that the difference between the expected power balance and the expected power total loss exceed the predetermined threshold.