An uninterruptible power supply (UPS) for a three-phase alternating current network, in particular a medium-voltage network, includes an energy storage system, a switch, an LC resonant circuit, which is a series circuit of an inductance and a capacitance, and a control unit for controlling the switch. The switch and the LC resonant circuit are connected in series, and the series circuit of the switch and the LC resonant is arranged between a network feed and the energy storage system which is connected to a load. There is also described a method for operating such a UPS and a corresponding computer program.

An uninterruptible power supply (UPS) for a three-phase alternating current network, in particular a medium-voltage network, includes an energy storage system, a switch, an LC resonant circuit, which is a series circuit of an inductance and a capacitance, and a control unit for controlling the switch. The switch and the LC resonant circuit are connected in series, and the series circuit of the switch and the LC resonant is arranged between a network feed and the energy storage system which is connected to a load. There is also described a method for operating such a UPS and a corresponding computer program.

Methods, systems, and computer readable mediums for protecting and controlling a microgrid with a dynamic boundary are disclosed. One method includes detecting a fault in a microgrid that includes a dynamic point-of-common-coupling (PCC), in response to determining that the microgrid is operating in a grid-connected mode, isolating the fault by tripping a microgrid side smart switch and a grid side smart switch that are located immediately adjacent to the fault, initiating the reclosing of the grid side smart switch, and initiating the reclosing for the microgrid side smart switch via resynchronization if the grid side smart switch is successfully reclosed, and in response to determining that the microgrid is operating in an islanded mode, isolating the fault by tripping a microgrid side smart switch that is located immediately adjacent to the fault, and initiating the reclosing of the microgrid side smart switch.

Methods, systems, and computer readable mediums for protecting and controlling a microgrid with a dynamic boundary are disclosed. One method includes detecting a fault in a microgrid that includes a dynamic point-of-common-coupling (PCC), in response to determining that the microgrid is operating in a grid-connected mode, isolating the fault by tripping a microgrid side smart switch and a grid side smart switch that are located immediately adjacent to the fault, initiating the reclosing of the grid side smart switch, and initiating the reclosing for the microgrid side smart switch via resynchronization if the grid side smart switch is successfully reclosed, and in response to determining that the microgrid is operating in an islanded mode, isolating the fault by tripping a microgrid side smart switch that is located immediately adjacent to the fault, and initiating the reclosing of the microgrid side smart switch.

Provided in the present invention are a microgrid control system and a microgrid, the microgrid control system comprising: a grid-connected switch, an energy router, a first controller and a second controller; the first controller controls the grid-connected switch and sends a first control instruction; the second controller receives the first control instruction and responds to the first control instruction for controlling the energy router.

Provided in the present invention are a microgrid control system and a microgrid, the microgrid control system comprising: a grid-connected switch, an energy router, a first controller and a second controller; the first controller controls the grid-connected switch and sends a first control instruction; the second controller receives the first control instruction and responds to the first control instruction for controlling the energy router.

In a power supply system, a first route includes a first power supply connected to a first load. A second route includes a second power supply connected to a second load. A connection path connects the first and second routes at a connection point. The first power supply includes a voltage generator generating an operating voltage operating the first and second loads. The second power supply includes an electrical storage device charging based on power supplied from the voltage generator. A switching circuit includes a first switch having a diode component with an anode and a cathode being directed to the electrical storage device and the connection path, respectively, and is disposed between the connection point and the electrical storage device. A switch state controller outputs a switch-off command to the first switch when the electrical storage device is in the fully charged condition.

A power supply control apparatus includes: a first system configured to supply electric power of a first power supply to a first load; a second system configured to supply electric power of a second power supply to a second load; an inter-system switch capable of connecting the first system to the second system and disconnecting the first system from the second system; a battery switch capable of connecting the second power supply to the second system and disconnecting the second power supply from the second system; a primary ground fault detection unit configured to cut off the inter-system switch and conduct the battery switch when a ground fault of the first system or the second system is detected by the primary ground fault detection unit; a secondary ground fault detection unit as defined herein; and a failure determination unit as defined herein.

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.

The present disclosure relates to systems and methods to coordinate protective elements in an electric power system (EPS). In one embodiment, a system may include a Time vs Normalized Impedance Length subsystem to determine a first plurality of times of operation of a first protective element for a plurality of fault locations in the EPS and to determine a second plurality of times of operation of a second protective element for the plurality of fault locations in the EPS. A protective action subsystem may coordinate a response of the first protective element and the second protective element. The protective action subsystem may establish a pickup and a protective action for the second protective element. Upon detection of a fault in the EPS, one of the first protective action and the second protective action may be implemented based on one of the first pickup and the second pickup.