An uninterruptible power supply (UPS) system is provided. The UPS system includes a plurality of UPSs, a ring bus coupled to the UPSs, a plurality of chokes, and at least one static switch coupled between an associated UPS of the UPSs and the ring bus. Each choke electrically couples an associated UPS to the ring bus. The static switch is switchable to selectively bypass at least one choke.

The disclosure relates to a power distribution protection system and a method thereof. The system includes: a main input unit configured to receive an alternating current power input; a electronic switch; a isolating switch; a main output unit configured to output alternating current power; a main-circuit automatic detection unit configured to detect a parameter of output from the electronic switch in a disconnection state of the isolating switch; a main control unit configured to determine whether a state of the electronic switch is normal based on electrical parameter information detected by the main-circuit automatic detection unit; the main input unit, the electronic switch, the isolating switch and the main output unit are connected in series. When the state of the electronic switch is normal, the isolating switch is closed, and then the electronic switch is turned on. When the state of the electronic switch is abnormal, the isolating switch remains disconnected.

A method and a controller for protecting an electrical distribution system are disclosed. The electrical distribution system comprises an electrical grid being electrically coupled to an electrical branch. The electrical branch comprises a plurality of switches for connecting or disconnecting the electrical branch at respective positions on the electrical branch, wherein a load is electrically coupled to a node on the electrical branch. The method comprises: detecting a fault occurrence on the electrical branch based on a monitored voltage and/or current of the electrical branch; limiting, based on the detecting a fault occurrence, a power flow from the node to the load; adjusting, based on the detecting a fault occurrence, a voltage and/or current on the electrical branch; determining a fault location based on the adjusted voltage and/or current on the electrical branch; and disconnecting a portion of the electrical distribution system based on the determined fault location.