A monitoring system includes an array of optical sensors disposed within a transformer tank. Each optical sensor is configured to have an optical output that changes in response to a temperature within the transformer tank. An analyzer is coupled to the array of optical sensors. The analyzer is configured to determine a sensed temperature distribution based on the sensed temperature. The sensed temperature distribution is compared to an expected distribution. Exterior contamination of the transformer tank is detected based on the comparison.

A transformer test device (10) for testing a transformer (40) has connections (12) for releasably connecting the transformer test device (10) to the transformer (40). The transformer test device (10) has a source (13) for generating a test signal for testing the transformer (40). The transformer test device (10) has a controllable switching means (15) which is connected to the connections (12) during a transformer test for the purpose of short-circuiting at least one winding (42) of the transformer (40).

A transformer test device (10) for testing a transformer (40) has connections (12) for releasably connecting the transformer test device (10) to the transformer (40). The transformer test device (10) has a source (13) for generating a test signal for testing the transformer (40). The transformer test device (10) has a controllable switching means (15) which is connected to the connections (12) during a transformer test for the purpose of short-circuiting at least one winding (42) of the transformer (40).

A method determines temperature information associated with a current coil connection in a meter. The method includes conveying heat from a current coil connection to a location proximate a winding disposed about a core. The core includes an opening through which a current carrying coil is disposed, the current carrying coil carrying current measured by the meter. The method also includes measuring a resistance of the winding disposed about a core, wherein the winding has a resistance that varies as a function of temperature. The method includes determining a temperature value based on the measured resistance and storing or communicating the determined temperature value.

A method for protecting a three-winding transformer of a wind turbine includes estimating, via a controller, an electrical condition of the primary winding of the transformer. The method also includes determining, via the controller, an electrical condition limit of the primary winding. The method also includes comparing, via the controller, the estimated electrical condition to the electrical condition limit. Further, the method includes implementing a corrective action for the wind turbine if the estimated electrical condition exceeds the electrical condition limit so as to reduce the electrical condition within safe limits.

A method for protecting a three-winding transformer of a wind turbine includes estimating, via a controller, an electrical condition of the primary winding of the transformer. The method also includes determining, via the controller, an electrical condition limit of the primary winding. The method also includes comparing, via the controller, the estimated electrical condition to the electrical condition limit. Further, the method includes implementing a corrective action for the wind turbine if the estimated electrical condition exceeds the electrical condition limit so as to reduce the electrical condition within safe limits.

The present disclosure relates to methods and devices for calculating winding currents at a delta side for a transformer. The transformer has two or more windings, with a first winding being a delta connected winding. The method includes obtaining line currents measured with measurement equipment associated with lines connected with the windings. The method further includes calculating zero sequence currents for at least a second winding, from the line currents of a corresponding line. The method further includes calculating zero sequence currents for the first winding, based on the zero sequence currents for at least the second winding, a phase displacement between the windings, and a turns ratio associated with the windings. The winding currents is calculated from the zero sequence currents of the first winding, and the line currents of a corresponding line.

The present disclosure relates to methods and devices for calculating winding currents at a delta side for a transformer. The transformer has two or more windings, with a first winding being a delta connected winding. The method includes obtaining line currents measured with measurement equipment associated with lines connected with the windings. The method further includes calculating zero sequence currents for at least a second winding, from the line currents of a corresponding line. The method further includes calculating zero sequence currents for the first winding, based on the zero sequence currents for at least the second winding, a phase displacement between the windings, and a turns ratio associated with the windings. The winding currents is calculated from the zero sequence currents of the first winding, and the line currents of a corresponding line.

The disclosure discloses a power transformer winding fault positioning method based on deep convolutional neural network integrated with visual identification, including 1) a winding equivalent circuit is established, and a transfer function thereof is calculated; 2) a sine wave excitation source is set at one end of the power transformer winding to obtain the amplitude-frequency characteristic curve of each winding node; 3) circuits under various fault statuses are subjected to scanning frequency response analysis to extract amplitude-frequency characteristics; 4) a feature matrix is established based on the obtained amplitude-frequency characteristics; 5) scanning frequency response analysis is performed on the diagnosed power transformer to form a feature matrix; 6) the feature matrix is converted into an image, simulation and historical detection data are used as a training set, and a deep convolutional neural network is input for training; 7) diagnosed transformer is subjected to fault classification and positioning.

A hardware-based detection system includes, among other things, a signal-generating circuit for generating a signal which is functionally related to current in a motor winding, a reference current, and a duration of time. The system may also include a comparator circuit for comparing the generated signal to a reference signal, and for thereby detecting an over-temperature condition in the motor winding. If desired, a compensating circuit may be used to generate a variable reference signal as a function of ambient temperature. A method of operating a detection system is also disclosed. If desired, the detection system may be completely implemented in hardware using an uncomplicated analog circuit architecture.