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.

A system and method for differential protection of a transformer under geomagnetically induced current (GIC). The method including: receiving differential currents associated with the transformer; outputting a high GIC signal where second harmonic phasors of the differential currents are in a negative-sequence format and at least one magnitude of the second harmonic phasors is greater than a magnitude threshold, or waveforms of three phases of the differential currents are all asymmetrical in a positive or negative direction; determining derivatives of the differential currents of three phases of the transformer; outputting a high supplementary signal where at least one of the derivatives of the differential currents is greater than a supplementary threshold; combining the GIC signal with the supplementary signal; combining the supplemented GIC signal with a second harmonic blocking signal; and outputting a trip signal for electrically tripping the transformer based on a supplemented second harmonic blocking signal.

A system and method for differential protection of a transformer under geomagnetically induced current (GIC). The method including: receiving differential currents associated with the transformer; outputting a high GIC signal where second harmonic phasors of the differential currents are in a negative-sequence format and at least one magnitude of the second harmonic phasors is greater than a magnitude threshold, or waveforms of three phases of the differential currents are all asymmetrical in a positive or negative direction; determining derivatives of the differential currents of three phases of the transformer; outputting a high supplementary signal where at least one of the derivatives of the differential currents is greater than a supplementary threshold; combining the GIC signal with the supplementary signal; combining the supplemented GIC signal with a second harmonic blocking signal; and outputting a trip signal for electrically tripping the transformer based on a supplemented second harmonic blocking signal.

System and method for detecting turn-to-turn faults in one or more windings of various objects are provided. In one implementation, a fault detector receives a set of current measurements associated with a transformer and uses these measurements to execute a procedure for detecting a turn-to-turn fault in the transformer. The procedure can include dividing a steady-state differential current value by a steady-state voltage value to obtain one or more compensating factors, determining a magnetizing current amplitude indicator by multiplying the steady-state voltage value by the one or more compensating factors, determining a compensated differential current value by combining the steady-state differential current value with a modifier value that incorporates the magnetizing current amplitude indicator, comparing the compensated differential current value against a threshold value, and declaring an occurrence of the turn-to-turn fault in the transformer when the compensated differential current value exceeds the threshold value.

System and method for detecting turn-to-turn faults in one or more windings of various objects are provided. In one implementation, a fault detector receives a set of current measurements associated with a transformer and uses these measurements to execute a procedure for detecting a turn-to-turn fault in the transformer. The procedure can include dividing a steady-state differential current value by a steady-state voltage value to obtain one or more compensating factors, determining a magnetizing current amplitude indicator by multiplying the steady-state voltage value by the one or more compensating factors, determining a compensated differential current value by combining the steady-state differential current value with a modifier value that incorporates the magnetizing current amplitude indicator, comparing the compensated differential current value against a threshold value, and declaring an occurrence of the turn-to-turn fault in the transformer when the compensated differential current value exceeds the threshold value.

Disclosed is a system that reduces fault currents in a power grid, thereby reducing the risk of unintentionally igniting a fire when an object comes in proximity to a high voltage power line. The circuit comprises an isolation transformer, a neutral connection, a current compensating device, and an automatic recloser or other circuit interrupting type protection system. The isolation transformer may comprise a delta-delta or delta-zigzag transformer with a one-to-one ratio between the input and output voltages and phase angle. The current compensating device is connected to the neutral and configured to redirect a substantial portion of a fault current to ground through the isolation transformer neutral instead of the fault itself. The current compensating device may comprise an arc suppression coil tuned to match the capacitance of the three phase outputs, or an inverter.

Disclosed is a system that reduces fault currents in a power grid, thereby reducing the risk of unintentionally igniting a fire when an object comes in proximity to a high voltage power line. The circuit comprises an isolation transformer, a neutral connection, a current compensating device, and an automatic recloser or other circuit interrupting type protection system. The isolation transformer may comprise a delta-delta or delta-zigzag transformer with a one-to-one ratio between the input and output voltages and phase angle. The current compensating device is connected to the neutral and configured to redirect a substantial portion of a fault current to ground through the isolation transformer neutral instead of the fault itself. The current compensating device may comprise an arc suppression coil tuned to match the capacitance of the three phase outputs, or an inverter.

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.

Detection of, and protection against faults within a restricted earth fault (REF) zone of a transformer or a generator is disclosed herein. Security of the REF protection element uses comparison of a negative-sequence reference quantity. The REF condition is only detected when there is sufficient ground involvement and a fault in the reverse detection has not been detected. Dependability of the REF protection element in low-impedance grounded systems is improved by ensuring that the element operates when a zero-sequence reference quantity and a neutral operate quantity are orthogonal to each other. The REF protection element further determines an open CT condition and blocks detection of an REF fault upon determination of the open CT condition. A tripping subsystem may issue a trip command based upon detection of the REF condition.

Detection of, and protection against faults within a restricted earth fault (REF) zone of a transformer or a generator is disclosed herein. Security of the REF protection element uses comparison of a negative-sequence reference quantity. The REF condition is only detected when there is sufficient ground involvement and a fault in the reverse detection has not been detected. Dependability of the REF protection element in low-impedance grounded systems is improved by ensuring that the element operates when a zero-sequence reference quantity and a neutral operate quantity are orthogonal to each other. The REF protection element further determines an open CT condition and blocks detection of an REF fault upon determination of the open CT condition. A tripping subsystem may issue a trip command based upon detection of the REF condition.