A method of clearing a fault in a high voltage DC electrical network, including power converters interconnected by a DC power transmission, comprising: detecting a fault in the DC power transmission and reconfiguring each power converter to a fault blocking mode drinving the DC fault current towards zero; locating the fault and isolating a faulty portion from a healthy remaining portion; reconfiguring one of the power converters designated as a re-energising power converter from the fault blocking to re-energise the healthy remaining portion; and detecting a rise in the voltage level in the healthy remaining portion above a threshold level and reconfiguring the remaining power converter connected with the healthy remaining portion from the fault blocking to the normal power transmission.

A system of surge suppressor units is connected at multiple locations on a power transmission and distribution grid to provide grid level protection against various disturbances before such disturbances can reach or affect facility level equipment. The surge suppressor units effectively prevent major voltage and current spikes from impacting the grid. In addition, the surge suppressor units include various integration features which provide diagnostic and remote reporting capabilities required by most utility operations. As such, the surge suppressor units protect grid level components from major events such as natural geomagnetic disturbances (solar flares), extreme electrical events (lightning) and human-generated events (EMPs) and cascading failures on the power grid.

A system of surge suppressor units is connected at multiple locations on a power transmission and distribution grid to provide grid level protection against various disturbances before such disturbances can reach or affect facility level equipment. The surge suppressor units effectively prevent major voltage and current spikes from impacting the grid. In addition, the surge suppressor units include various integration features which provide diagnostic and remote reporting capabilities required by most utility operations. As such, the surge suppressor units protect grid level components from major events such as natural geomagnetic disturbances (solar flares), extreme electrical events (lightning) and human-generated events (EMPs) and cascading failures on the power grid.

In aspects, the present invention provides a method for controlled energizing of a transformer (150) being connected to a first electrical subsystem (110) through a first circuit breaker (140). The method comprises acquiring electrical current waveform in a first phase of the transformer during a closing operation of the first circuit breaker at an instance for switching determined by a controller (130), determining a first peak (310) in the current in the first phase within a first predetermined time window (Tpw), calculating a first correction factor for adjusting the instance for switching in the first phase, and adjusting the instance for switching based on the calculated first correction factor for performing a next controlled energization at the adjusted instance of switching in the first phase.

In aspects, the present invention provides a method for controlled energizing of a transformer (150) being connected to a first electrical subsystem (110) through a first circuit breaker (140). The method comprises acquiring electrical current waveform in a first phase of the transformer during a closing operation of the first circuit breaker at an instance for switching determined by a controller (130), determining a first peak (310) in the current in the first phase within a first predetermined time window (Tpw), calculating a first correction factor for adjusting the instance for switching in the first phase, and adjusting the instance for switching based on the calculated first correction factor for performing a next controlled energization at the adjusted instance of switching in the first phase.

Embodiments of the present invention include a test-boost electric power recloser that limits the duration of the test current imposed on the power line to less than two electric power cycles, and preferably less than one electric power cycle, when attempting to reclose into a fault. The test-boost recloser sends a test pulse causing a non-latching close followed by a boost pulse causing a latching close if waveform analysis based on the test close indicates that the fault has likely cleared. The test-boost approach can typically be implemented through a software and calibration upgrade to a conventional single-coil recloser, accomplishing results comparable to a dual-actuator recloser at a much lower cost. The recloser may perform iterative and feedback learning feedback processes to automatically improve its operation over time in response to measured fault and non-fault conditions and its success in predicting whether faults have cleared.

The present disclosure relates to a method for protecting DC line impedance phase based on protection and control coordination, and an application scenario of the method for protecting is a three-terminal flexible DC transmission network. The method uses high controllability of a converter after a fault, injects a characteristic signal at a characteristic frequency, and calculates a phase angle of input impedance to determine a fault interval, which effectively improves protection performance, turns passive to active, and is not affected by nonlinearity of the converter. At the same time, compared with a full-bridge MMC, using a half-bridge MMC does not need to perform fault ride-through first when identifying a fault, and does not need to add additional equipment, it creates fault features and can reliably identify an fault interval; improves protection quickness and at the same time also has better economic benefits. It has selectivity, and an entire system may not be shut down due to failure of a single line.

A safe energy supply unit (1) and system, for supplying an electrical device (8) in an explosion-proof area, transmits power from an energy source (9), including a plurality of galvanically isolated individual sources, with a multiple line connection (2) with a plurality of galvanically isolated and individually shielded conductor pairs (31, 32, 33, 34). A collector device (4), in an explosion-proof jacket (5) at an end of the multiple line (3), has uncoupling devices (45) for the galvanically isolated conductor pairs and a combiner circuit (47, 49) that combines the transmitted electric power from each line into a global power. The global power is outputted at an output (48) of the collector device to the electrical device. The conductor pairs allow for an increased global power, which is scalable, safely transmittable, with standard, conductor pairs. The electrical device is intrinsically safely supplied with high power with minimal effort.

A safe energy supply unit (1) and system, for supplying an electrical device (8) in an explosion-proof area, transmits power from an energy source (9), including a plurality of galvanically isolated individual sources, with a multiple line connection (2) with a plurality of galvanically isolated and individually shielded conductor pairs (31, 32, 33, 34). A collector device (4), in an explosion-proof jacket (5) at an end of the multiple line (3), has uncoupling devices (45) for the galvanically isolated conductor pairs and a combiner circuit (47, 49) that combines the transmitted electric power from each line into a global power. The global power is outputted at an output (48) of the collector device to the electrical device. The conductor pairs allow for an increased global power, which is scalable, safely transmittable, with standard, conductor pairs. The electrical device is intrinsically safely supplied with high power with minimal effort.

In a method for protecting lines, in which a reactor device for reactive power compensation is provided on an electrical line, a resonant current is measured on the line side of the reactor device by a first measuring device after an opening of a circuit breaker. A voltage is measured by a second measuring device after the opening of the circuit breaker. A current in the reactor device is calculated by an evaluation device on a basis of the measured voltage, and the calculated current is subtracted from the measured resonant current by the evaluation device in order to obtain a corrected current.