A power converter and a control method thereof are provided. The power converter includes a primary side switching circuit, a secondary side switching circuit, a transformer, and a control circuit. The primary side switching circuit includes a first set of switches. The secondary side switching circuit includes a second set of switches. The transformer is coupled between the primary side switching circuit and the secondary side switching circuit. The control circuit is configured to control power transfer between the primary side switching circuit and the secondary side switching circuit by controlling the first and second sets of switches. The control circuit is adapted to enable and disable the first and second sets of switches in an enabling duration and a disabling duration respectively and alternatively.

Provided is a detecting device and a method for detecting a fault in a transformer of a wind turbine, wherein the transformer transforms a lower voltage, which is output from a generator of the wind turbine to a low voltage side of the transformer, to a higher voltage, which is output from the transformer at a high voltage side, the detecting device including: a voltage detection device configured to detect a voltage at a first node at the low voltage side of the transformer; a current detection device configured to detect a current at a second node at the high voltage side of the transformer. The detecting device is configured to detect the fault in the transformer based on the detected voltage and the detected current.

A protection circuit is disclosed. The protection circuit includes a direct current (DC) blocking component electrically connected between a neutral of the transformer and a ground, and an overvoltage protection device electrically connected in parallel with the DC blocking component. The overvoltage protection device is constructed to repeatably and reliably provide overvoltage protection in response to a voltage at the transformer neutral above a threshold. The DC blocking component has an impedance below a predetermined value, thereby effectively grounding the neutral of the transformer. The DC blocking component is persistently maintained in connection to the transformer neutral.

Systems, devices, and methods for a transformer including: a first drive winding (206) wound on a first core; a second drive winding wound on a second core; a sense winding wound across the first and second cores; and a compensation winding wound across the first and second cores; where one or more utility lines are threaded through a middle of the first and second cores, a common mode current in the one or more utility lines causes one or more pulses to appear on the sense winding, a current on the compensation winding is adjusted until the one or more pulses on the sense winding are cancelled out, and the common mode current on the one or more utility lines is the adjusted current on the compensation winding multiplied by a turn ratio between the compensation winding and the sense winding.

A differential protection method allows monitoring a three-phase transformer. Current measured values are recorded for each phase on all sides of the transformer, a phase-related formation of difference values is carried out using the current measured values from a reference side and amplitude-adjusted and phase-angle-adjusted current measured values from all other sides. An internal error is detected if a difference value exceeds a threshold value. In order to form the amplitude-adjusted and phase-angle-adjusted current measured values, the current measured values recorded for all phases are initially subjected to an amplitude adjustment and then to a phase angle adjustment. In order to allow the phase angle shift to be freely adjusted, a defined matrix equation with a defined matrix coefficient is used for the phase angle adjustment of the current measured values from the particular other side of the transformer. There is also described a differential protection device.

A differential protection method allows monitoring a three-phase transformer. Current measured values are recorded for each phase on all sides of the transformer, a phase-related formation of difference values is carried out using the current measured values from a reference side and amplitude-adjusted and phase-angle-adjusted current measured values from all other sides. An internal error is detected if a difference value exceeds a threshold value. In order to form the amplitude-adjusted and phase-angle-adjusted current measured values, the current measured values recorded for all phases are initially subjected to an amplitude adjustment and then to a phase angle adjustment. In order to allow the phase angle shift to be freely adjusted, a defined matrix equation with a defined matrix coefficient is used for the phase angle adjustment of the current measured values from the particular other side of the transformer. There is also described a differential protection device.

Signal transducers in electrical communication with shorted leads of current transformers are used to provide monitoring and protection functions to an electric power delivery system. Differential protection is performed by comparing a predetermined threshold against a voltage signal from series-connected leads of signal transducers in electrical communication with shorted leads of current transformers. The signal transducers may be Rogowski coils. Signal transducers in communication with shorted leads may be used to improve safety and increase performance of the current transformers by decreasing susceptibility to saturation.

A differential protection method for generating a fault signal includes measuring current measurements at least at two different measuring points of a multiphase transformer for each phase. The current measurements for each phase are used to form differential current values and stabilization values. The fault signal is generated if it is determined during a trigger region check that a measurement pair of at least one of the phases, being formed by using one of the differential current values and the associated stabilization value in each case, is in a predefined trigger region. In order to be able to selectively and reliably distinguish an external fault from an internal fault, the transformer has a grounded star point and a zero system current flowing through the star point is used to form the stabilization values. A corresponding differential protection device is provided for performing the differential protection method.

A differential protection method for generating a fault signal includes measuring current measurements at least at two different measuring points of a multiphase transformer for each phase. The current measurements for each phase are used to form differential current values and stabilization values. The fault signal is generated if it is determined during a trigger region check that a measurement pair of at least one of the phases, being formed by using one of the differential current values and the associated stabilization value in each case, is in a predefined trigger region. In order to be able to selectively and reliably distinguish an external fault from an internal fault, the transformer has a grounded star point and a zero system current flowing through the star point is used to form the stabilization values. A corresponding differential protection device is provided for performing the differential protection method.

Embodiments of the disclosure relate to detecting turn-to-turn faults in one or more windings of various objects. In one implementation, a fault detector uses a differential protection algorithm to detect a turn-to-turn fault in a winding of a three-phase shunt reactor. Various voltage and current measurements carried out upon the three-phase shunt reactor are used to calculate a difference value between a voltage-based parameter and a current-based parameter. The voltage-based parameter is indicative of a normalized negative voltage imbalance and the current-based parameter is indicative of a normalized negative current imbalance. A turn-to-turn winding fault is declared when the difference value is not equal to zero.