Abstract: A method for restoration of a fault isolation in a medium voltage, MV, network having a plurality of feeders and a plurality of normally open, NO, switches possibly in parallel with MV direct current, DC, links is presented. The method is performed in a control device of the MV network. The method includes closing at least two NO switches in parallel with MVDC links of the plurality of NO switches, being connected to a fault isolated feeder of the plurality of feeders of the MV network, and opening the closed at least two NO switches in parallel with MVDC links except one. A control device, a computer program and a computer program product for restoration of a fault isolation in a MV network are also presented.

Abstract: A transformer arrangement is provided. The transformer arrangement includes a transformer with a primary and a secondary winding and a chain link of switching blocks connected in series between one of the windings and a load, where the switching blocks comprise a first set of voltage contribution blocks and a second set of circuit breaker blocks, where the first set of voltage contribution blocks is configured to adjust a voltage output by the transformer with an offset voltage and the second set of circuit breaker blocks is configured to interrupt a current running through the chain link.

Abstract: Provided is a transformer arrangement wherein active and/or reactive power can be injected in an alternating current link using a current regulator and a voltage regulator portion, wherein at least one winding with which the current regulator is connected in parallel is at least one tertiary winding, and wherein the current regulator includes a number of current regulator sections, each connected to a corresponding voltage regular section of a voltage regulator portion via a corresponding dc link.

Abstract: A vehicular power system includes a battery branch including a battery unit arranged in series with a diode, and a high-capacity unit having a maximum voltage that exceeds a nominal voltage of the battery unit. The battery branch and high-capacity unit are arranged in parallel, to feed a load side of the vehicular power system. The battery branch further includes a switching arrangement configured to disconnect the battery unit in response to excessive load-side current. The switching arrangement may allow the high-capacity unit to inject current into the load side at a voltage less than the nominal voltage of the battery unit and/or may allow the high-capacity unit to absorb regenerated current from the load side at a voltage which is greater than the nominal voltage of the battery unit.

Abstract: A transformer arrangement is provided. The transformer arrangement includes a transformer with a primary and a secondary winding and a chain link of switching blocks connected in series between one of the windings and a load, where the switching blocks comprise a first set of voltage contribution blocks and a second set of circuit breaker blocks, where the first set of voltage contribution blocks is configured to adjust a voltage output by the transformer with an offset voltage and the second set of circuit breaker blocks is configured to interrupt a current running through the chain link.

Abstract: An onboard powertrain for an automated guided vehicle, AGV, is presented herein. The onboard powertrain includes a split-source inverter, SSI, having at least one middle point pole, a positive DC-link pole, and a negative DC-link pole, a battery and an inductor connected in series between the positive or negative DC-link pole and the middle point pole, and a supercapacitor connected between the positive and negative DC-link poles.

Abstract: One embodiment is a system comprising a medium voltage direct current (MVDC) link electrically coupling a first AC-DC converter and a second AC-DC converter. The first AC-DC converter is electrically coupled with a first alternating current (AC) feeder. The second AC-DC converter electrically coupled with a second AC feeder. A battery charger electrically coupled with the MVDC link via a converterless connection. A first electronic controller is operatively coupled with the first AC-DC converter. A second electronic controller is operatively coupled with the second AC-DC converter. During operation of the battery charger to charge a battery the first electronic controller is configured to control power flow between the first AC feeder and the second AC feeder and the second electronic controller is configured to control the voltage of the MVDC link.

Abstract: Provided is a transformer arrangement wherein active and/or reactive power can be injected in an alternating current link using a current regulator and a voltage regulator portion, wherein at least one winding with which the current regulator is connected in parallel is at least one tertiary winding, and wherein the current regulator includes a number of current regulator sections, each connected to a corresponding voltage regular section of a voltage regulator portion via a corresponding dc link.

Abstract: A method for restoration of a fault isolation in a medium voltage, MV, network having a plurality of feeders and a plurality of normally open, NO, switches possibly in parallel with MV direct current, DC, links is presented. The method is performed in a control device of the MV network. The method includes closing at least two NO switches in parallel with MVDC links of the plurality of NO switches, being connected to a fault isolated feeder of the plurality of feeders of the MV network, and opening the closed at least two NO switches in parallel with MVDC links except one. A control device, a computer program and a computer program product for restoration of a fault isolation in a MV network are also presented.

Abstract: Unique systems, methods, techniques and apparatuses of fault mitigation are disclosed. One exemplary embodiment is a fault mitigation system for a medium voltage alternating current (MVAC) distribution network including a direct current (DC) link and a control system. The DC link is coupled to a first feeder line and a second feeder line. The control system is structured to determine a first feeder line is deenergized, operate the DC link so as to receive MVAC from a second feeder line and output low voltage alternating current (LVAC) to the first feeder line, operate a plurality of isolation devices, measure the LVAC in response to operating the plurality of isolation devices, determine a fault is isolated from a healthy portion of the first feeder line using the received LVAC measurements, and reenergize the healthy portion of the first feeder line.

Abstract: Unique systems, methods, techniques and apparatuses of a distribution system are disclosed. One exemplary embodiment is an alternating current (AC) distribution system including a first substation including a first transformer and a protective device; a first distribution network portion coupled to the first transformer; a second substation; a second distribution network portion; a DC interconnection system coupled between the first distribution network portion and the second distribution network portion; and a control system. The control system is structured to detect a fault in the first transformer or the transmission network, isolate the first distribution network from the fault, determine a set point of the DC interconnection system, and operate the DC interconnection system using the set point so as to transfer a portion of the MVAC from the second distribution network portion to the first distribution network portion.

Abstract: A multiphase current-fed modular multilevel converter, CMMC, is presented. The CMMC includes a plurality of cascaded submodules, SMs, connected in series between ground point and an alternating current, AC, voltage output point, wherein each SM has a connectable series capacitor , a blocking diode connected between an input direct current, DC, source point and the AC voltage output point, wherein each phase of the multiphase CMMC has an arm of the plurality of cascaded SMs and the blocking diode, and an input DC source connected between ground and the input DC source point. An output AC voltage is drawn differentially between two of the arms.

Abstract: Systems, methods, techniques, and apparatuses of a medium voltage alternating current (MVAC) network are disclosed. One exemplary embodiment is a direct current (DC) interconnection system for an MVAC distribution network including an AC/AC power converter including a first AC terminal and a second AC terminal; a plurality of switching devices structured to selectively couple a first AC terminal to a plurality of feeder line points in the MVAC network; and a control system structured to receive a set of measurements, calculate a headroom value for each feeder line point using the set of measurements, select a first feeder line point using the calculated headroom values, operate the plurality of switching devices so as to couple the first AC terminal to the first feeder line point, and operate the AC/AC power converter so as to transmit MVAC power from the first AC terminal to the first feeder line point.

Abstract: One embodiment is a system comprising a medium voltage direct current (MVDC) link electrically coupling a first AC-DC converter and a second AC-DC converter. The first AC-DC converter is electrically coupled with a first alternating current (AC) feeder. The second AC-DC converter electrically coupled with a second AC feeder. A battery charger electrically coupled with the MVDC link via a converterless connection. A first electronic controller is operatively coupled with the first AC-DC converter. A second electronic controller is operatively coupled with the second AC-DC converter. During operation of the battery charger to charge a battery the first electronic controller is configured to control power flow between the first AC feeder and the second AC feeder and the second electronic controller is configured to control the voltage of the MVDC link.

Abstract: Systems, methods, techniques and apparatuses of feeder line fault response are disclosed. One exemplary embodiment is a method for operating an alternating current (AC) distribution network including a first feeder line, a second feeder line, and a third feeder line. The method includes isolating a faulted portion of the first feeder line from a healthy portion of the first feeder line; closing a tie switch coupled between the healthy portion and the second feeder line in response to isolating the faulted portion from the healthy portion; determining the second feeder line is experiencing an overload condition after closing the tie switch; and transferring AC power including transferring AC power using a direct current (DC) interconnection system coupled to the third feeder line effective to remove the overload condition from the second feeder line.

Abstract: Systems, methods, techniques and apparatuses of feeder line fault response are disclosed. One exemplary embodiment is a method for operating an alternating current (AC) distribution network including a first feeder line, a second feeder line, and a third feeder line. The method includes isolating a faulted portion of the first feeder line from a healthy portion of the first feeder line; closing a tie switch coupled between the healthy portion and the second feeder line in response to isolating the faulted portion from the healthy portion; determining the second feeder line is experiencing an overload condition after closing the tie switch; and transferring AC power including transferring AC power using a direct current (DC) interconnection system coupled to the third feeder line effective to remove the overload condition from the second feeder line.

Abstract: Unique systems, methods, techniques and apparatuses of a distribution system are disclosed. One exemplary embodiment is an alternating current (AC) distribution system including a first substation including a first transformer and a protective device; a first distribution network portion coupled to the first transformer; a second substation; a second distribution network portion; a DC interconnection system coupled between the first distribution network portion and the second distribution network portion; and a control system. The control system is structured to detect a fault in the first transformer or the transmission network, isolate the first distribution network from the fault, determine a set point of the DC interconnection system, and operate the DC interconnection system using the set point so as to transfer a portion of the MVAC from the second distribution network portion to the first distribution network portion.

Abstract: Systems, methods, techniques, and apparatuses of a medium voltage alternating current (MVAC) network are disclosed. One exemplary embodiment is a direct current (DC) interconnection system for an MVAC distribution network including an AC/AC power converter including a first AC terminal and a second AC terminal; a plurality of switching devices structured to selectively couple a first AC terminal to a plurality of feeder line points in the MVAC network; and a control system structured to receive a set of measurements, calculate a headroom value for each feeder line point using the set of measurements, select a first feeder line point using the calculated headroom values, operate the plurality of switching devices so as to couple the first AC terminal to the first feeder line point, and operate the AC/AC power converter so as to transmit MVAC power from the first AC terminal to the first feeder line point.

Abstract: Unique systems, methods, techniques and apparatuses of fault mitigation are disclosed. One exemplary embodiment is a fault mitigation system for a medium voltage alternating current (MVAC) distribution network including a direct current (DC) link and a control system. The DC link is coupled to a first feeder line and a second feeder line. The control system is structured to determine a first feeder line is deenergized, operate the DC link so as to receive MVAC from a second feeder line and output low voltage alternating current (LVAC) to the first feeder line, operate a plurality of isolation devices, measure the LVAC in response to operating the plurality of isolation devices, determine a fault is isolated from a healthy portion of the first feeder line using the received LVAC measurements, and reenergize the healthy portion of the first feeder line.

Abstract: A converter converting between a dc voltage at a first voltage level and at least one waveshape at a second higher voltage level has a primary connection port for the dc voltage, one secondary connection port for each waveshape, and one stack of cells for each secondary port. Each stack includes n cells connected in cascade between the primary port and the corresponding secondary port. At least (n?1) of the cells in a stack have: first, second, third, and fourth terminals, a first energy storage, and first, second, and third switches, where the first energy storage is connected in parallel with the first and second switches, the first terminal is provided at a junction between the first energy storage and the first switch, and the second terminal is provided at a junction between the first energy storage element, the second switch and the third switch.