The invention is related to a monitoring and protection device of power distribution transformers on the low voltage side. Said device monitors in a permanent manner the functioning of the transformer and provides a record of all the information in case of a fault. Additionally, the invention device provides the protection of the transformer in case of a fault, allowing a partial impact on the service and preventing peak currents that may reduce the useful life of the transformer. The device has a remote communication module that allows the transmission of the recorded data, a control module that may be activated remotely and a visual alert module that reduces the risk in the handling of the device.

The invention is related to a monitoring and protection device of power distribution transformers on the low voltage side. Said device monitors in a permanent manner the functioning of the transformer and provides a record of all the information in case of a fault. Additionally, the invention device provides the protection of the transformer in case of a fault, allowing a partial impact on the service and preventing peak currents that may reduce the useful life of the transformer. The device has a remote communication module that allows the transmission of the recorded data, a control module that may be activated remotely and a visual alert module that reduces the risk in the handling of the device.

A fault detection system that that prevents a recloser from reclosing if a fault is determined to be internal to a transformer, where the recloser is configured to perform a reclosing operation in response to detecting overcurrent. The recloser includes a sensor, such as a light sensor, directed towards the transformer and detecting a fault event. If the recloser detects overcurrent, but the sensor does not detect the fault event, it is assumed that the fault is internal to the transformer and the recloser is prevented from reclosing.

A fault detection system that that prevents a recloser from reclosing if a fault is determined to be internal to a transformer, where the recloser is configured to perform a reclosing operation in response to detecting overcurrent. The recloser includes a sensor, such as a light sensor, directed towards the transformer and detecting a fault event. If the recloser detects overcurrent, but the sensor does not detect the fault event, it is assumed that the fault is internal to the transformer and the recloser is prevented from reclosing.

A protection circuit is for a medium voltage or high voltage transformer and includes a sensing device, a measurement device, and a switching device. The sensing device is configured to be connected between a primary winding of a voltage transformer and ground potential. The measurement device is connected to the sensing device and the measurement device is configured to measure at least one parameter sensed by the sensing device. The protection circuit is configured to analyse the measured at least one parameter sensed by the sensing device. The protection circuit is configured to generate a trip signal based on the analysis of the measured at least one parameter sensed by the sensing device. The switching device is configured to receive the generated trip signal and disconnect the voltage transformer from a high voltage potential.

A protection circuit is for a medium voltage or high voltage transformer and includes a sensing device, a measurement device, and a switching device. The sensing device is configured to be connected between a primary winding of a voltage transformer and ground potential. The measurement device is connected to the sensing device and the measurement device is configured to measure at least one parameter sensed by the sensing device. The protection circuit is configured to analyse the measured at least one parameter sensed by the sensing device. The protection circuit is configured to generate a trip signal based on the analysis of the measured at least one parameter sensed by the sensing device. The switching device is configured to receive the generated trip signal and disconnect the voltage transformer from a high voltage potential.

A method for suppressing magnetizing inrush current of the transformer with flux linkage control includes connecting a small-capacity direct current/alternating current (DC/AC) converter with the secondary winding or auxiliary winding of transformer, detecting the primary side phase voltage before closing load, inducing the core flux linkage reference according to the relationship between the winding voltage and core flux linkage. The core flux linkage closed-loop PI control system is constructed to control the converter voltage in the synchronous coordinate, then the core flux linkage can track its reference with no static error, thus the sinusoidal flux linkage with 90-degree difference from the grid voltage can be pre-established in the core before no-load closing. By these methods, no matter when the main transformer closes, the core flux linkage is always in the steady state, and the magnetizing inrush current can be eliminated completely.

A method for suppressing magnetizing inrush current of the transformer with flux linkage control includes connecting a small-capacity direct current/alternating current (DC/AC) converter with the secondary winding or auxiliary winding of transformer, detecting the primary side phase voltage before closing load, inducing the core flux linkage reference according to the relationship between the winding voltage and core flux linkage. The core flux linkage closed-loop PI control system is constructed to control the converter voltage in the synchronous coordinate, then the core flux linkage can track its reference with no static error, thus the sinusoidal flux linkage with 90-degree difference from the grid voltage can be pre-established in the core before no-load closing. By these methods, no matter when the main transformer closes, the core flux linkage is always in the steady state, and the magnetizing inrush current can be eliminated completely.

The invention provides a transformer short-circuit protection method and a transformer short-circuit protection device. The transformer short-circuit protection method includes: acquiring output voltages of a plurality of output lines of at least one winding on a low-voltage side of a transformer; and determining a short circuit according to the output voltages, and sending a protection signal when the short circuit is determined.

The invention provides a transformer short-circuit protection method and a transformer short-circuit protection device. The transformer short-circuit protection method includes: acquiring output voltages of a plurality of output lines of at least one winding on a low-voltage side of a transformer; and determining a short circuit according to the output voltages, and sending a protection signal when the short circuit is determined.