A battery inverter system includes a plurality of battery inverter units, wherein each of the battery inverter units includes a multiphase inverter and a battery unit connected to the inverter on the DC side. The battery unit includes a plurality of individual units connected in parallel to one another and protected against overcurrent by means of rack fuses, and the battery inverter units are connected in parallel on the AC side and are configured to operate with a common drive pulse pattern. The battery inverter units are interconnected on the DC side via compensation fuses, wherein the compensation fuses are provided such that in the event of a short circuit in one of the inverters, the compensation fuses are triggered faster than the rack fuses.

An overcurrent protection device is for protecting a load arranged in a DC grid. The load is coupled to a supply busbar, which is connectable to a supply potential of the DC grid, in the DC grid via the overcurrent protection device. The overcurrent protection device is designed to ascertain a current trigger value based upon a detected value of a current flowing through the overcurrent protection device and a trigger characteristic which is assigned to the load and is based on the current; compare the current trigger value with a threshold, and either trigger the overcurrent protection device or not, based upon the result of the comparison. The current is taken into consideration together with a first or a second factor in the trigger characteristic based upon the current direction.

A method for locating phase faults in a microgrid in off-grid mode. The method includes obtaining a grid topology of the microgrid having at least two busbars and determining the position of all circuit breaker position of the grid topology. Further, acquiring measurement data which includes current magnitude and voltage magnitude. Monitoring the at least two busbars for a voltage dip in one of phase-to-phase or phase-to-neutral voltages. On detecting a voltage dip, determining a defect phase having a minimum phase-to-neutral voltage value. And for the defect phase performing busbar analysis and feeder analysis, using phase-directional information.

There is disclosed a circuit breaker arrangement for interrupting a current flowing through a direct current (DC) transmission line including a semiconductor switching device and a pulse injection circuit configured to inductively inject into the transmission line a pulse current that opposes the current flowing through the transmission line to thereby reduce the current in the transmission line to cause the semiconductor switching device to turn-off to interrupt the path for the current flow through the transmission line.

A DC-overcurrent detector includes: at least one electric line passing the detector from a source terminal of the detector to a load terminal of the detector; at least one first sensor for monitoring an electric current in the at least one electric line and outputting a current measurement signal; at least one current flow direction sensor for distinguishing a current flow direction of the electric current in the at least one electric line between a first direction from the source terminal to the load terminal and a second direction from the load terminal to the source terminal, and outputting a current flow direction signal; a comparator unit for comparing an actual value of the current measurement signal with a threshold criterion, and outputting a trigger signal at a trigger output if a value of the current measurement signal reaches the threshold criterion; and a threshold criterion unit.

A load zone of a DC system includes a connection interface for supplying the load zone with electrical energy, an electronic switch arranged between the connection interface and a DC bus, and at least two electrical devices connected in parallel to the DC bus. A voltage sensor measures a voltage across a fuse arranged between the DC bus and a respective electrical device. An evaluation unit identifies a defective device of the at least two electrical devices based on a polarity of the voltage measured by the voltage sensor across the fuse. A DC system with such a load zone and an energy source connected to the connection interface of the load zone, as well as a method for operating such load zone or DC system are also disclosed. A device is identified as being defective when the voltage measured across the fuse exceeds a specified limit value.

The invention relates to a transient based method for identifying faults in an electric power transmission and/or distribution system (100) having at least one current transmission line (L.sub.12, L.sub.13, L.sub.23) comprising the following steps: —generation of a physical model of the at least one current transmission line (L.sub.12, L.sub.13, L.sub.23), the physical model depending on the fault parameters and describing the behavior of voltage and/or current transients due to the fault in the at least one current transmission line, fault parameters comprising a fault location parameter on said current transmission line (L.sub.12, L.sub.13, L.sub.23) and a fault impedance parameter, —measurement of voltage and/or currents evolution at least at one specific location in the said power system (100), —iterative simulation of the voltage and/or current evolution by the physical model at the measurement point with a set of fault parameters where at each step of iteration, simulated and measured voltage and/or current evolutions are compared and the set of fault parameters is adapted according to a convergence criterion, —identification of a fault with its fault parameters when convergence of the measured voltage and/or current evolutions and simulated voltage and/or current evolutions is reached in a limited number of iterations.

A electric aircraft power distribution system includes a first battery pack connected to at least a first load and to a common bus that connects the first battery pack in parallel to at least a second battery pack; a first electrical component electrically connected between the first battery pack and the first load and configured to disconnect the first load from the first battery pack in response to current above a first threshold current, wherein the first electrical component has a first disconnection time at the first threshold current; and a second electrical component electrically connected between the first battery pack and the common bus and configured to disconnect the first battery pack from the common bus in response to current above a second threshold current, wherein the second electrical component has a second disconnection time at the second threshold current that is higher than the first disconnection time.

A neutral arrangement is provided for a converter station of a direct current power transmission system that includes a first converter. The neutral arrangement includes surge arrestors and a group of neutral buses. Each surge arrestor is connected between a neutral bus and ground. The neutral arrangement includes a high voltage insulation zoom area having a first group of surge arrestors and a low voltage insulation zoom area having a second group of surge arrestors. The surge arrestors in the first group have a first arrestor reference voltage and the surge arrestors in the second group have a second arrestor reference voltage that is lower than the first arrestor reference voltage.

A bi-directional direct current (DC) solid state power controller (SSPC) architecture and control method. The SSPC protects a DC distribution system by isolating both the positive and negative buses independently in case of short circuit or ground fault. The SSPC architecture includes two self-heal interleaved capacitors and includes a fast, soft-charging control technique that provides line-isolated charging of the DC bulk capacitor to avoid inrush current when powering up the DC distribution system. The soft-charging function alternately charges one of the two interleaved capacitors, while the other capacitor discharges to the DC bulk capacitor. Repetitive switching results in a charging and discharging process that increases the voltage of the DC bulk capacitor prior to powering up the DC distribution system, while keeping the DC power source isolated from the load.