Protection methods and switches in uninterruptible power supply systems

A system comprising:

• a plurality of uninterruptible power supplies (UPSs);
• a ring bus;
• a plurality of chokes, each choke of said plurality of chokes electrically coupling an associated UPS of said plurality of UPSs to said ring bus;
• at least one switch electrically coupled between one choke of said plurality of chokes and said ring bus;
• a reactance or a resistor electrically coupled in parallel with said at least one switch;
• and
• at least one controller configured to control the at least one switch in response to detecting a fault condition in the system, wherein to control the at least one switch comprises to switch the at least one switch in less than 10 milliseconds in response to detecting the fault condition, and to control a frequency of an output voltage of each UPS of the plurality of UPSs by performing an open loop integration of the output voltage across one choke of the plurality of chokes and performing high pass filtering before and after the open loop integration.

At least one controller comprising;

• a processor;
• and
• a memory device communicatively coupled to said processor, said memory device storing executable instructions configured to cause said processor to:
• detect a fault condition in a power supply system that comprises a plurality of uninterruptible power supplies (UPSs), a ring bus, at least one switch electrically coupled between at least one UPS of the plurality of UPSs and the ring bus, and a plurality of chokes each electrically coupling an associated UPS of the plurality of UPSs to the ring bus;
• switch the at least one switch to address the fault condition in less than 10 milliseconds in response to detecting the fault condition;
• and
• control a frequency of an output voltage of one UPS of the plurality of UPSs by performing an open loop integration of the output voltage across one choke of the plurality of chokes and performing high pass filtering before and after the open loop integration.

A method comprising:

• detecting, using at least one controller, a fault condition in a power supply system that comprises a plurality of uninterruptible power supplies (UPSs), a ring bus, at least one switch electrically coupled between at least one UPS of the plurality of UPSs and the ring bus, and a plurality of chokes each electrically coupling an associated UPS of the plurality of UPSs to the ring bus;
• switching, in response to the at least one controller detecting the fault condition, the at least one switch in less than 10 milliseconds;
• and
• controlling a frequency of an output voltage of one UPS of the plurality of UPSs by performing an open loop integration of the output voltage across one choke of the plurality of chokes and performing high pass filtering before and after the open loop integration.