Apparatus for opening or closing a dc circuit, and method for automatically closing a dc circuit
AssigneeSiemens Aktiengesellschaft
InventorYi ZHU
Life of this patent
Estimating the term…
Abstract
A device is for opening or closing a DC circuit with at least one busbar. The device includes an electric switch for opening or closing the DC circuit; a fault current detector; a trigger unit and a precharging device. The electric switch opens the DC circuit via the trigger unit upon a fault current being detected by the fault current detector. Further, the precharging device restores the voltage on the busbar prior to closing the electric switch. The device further includes a control unit for automatically closing the electric switch after the pre-charging process.
Claims20
An apparatus for opening or closing a DC circuit including at least one busbar, the apparatus comprising:
- an electrical switch to open or close the DC circuit;
- a fault current detection device to detect existence of a fault current;
- a tripping unit;
- and
- a pre-charging apparatus,
- wherein, upon the fault current being detected by the fault current detection device, the electrical switch is configured to open the DC circuit via the tripping unit and the pre-charging apparatus is configured to restore voltage on the at least one busbar before the electrical switch is closed;
- and
- a control unit to automatically close the electrical switch after the restoration of the voltage on the at least one busbar.
A method for automatically closing a DC circuit via an apparatus, the method comprising:
- setting a counter to zero;
- determining existence of a fault current and, upon no fault current being determined, continue monitoring for a fault by at least
- incrementing the counter by one upon the fault current exceeding a current threshold and otherwise passing through a time-delaying tripping characteristic and setting the counter to two;
- opening the electrical switch;
- jumping to the setting of the counter to zero upon the counter being greater than or equal to two, otherwise:
- waiting to activate a pre-charging apparatus of the DC circuit:
- activating the pre-charging apparatus upon
- the voltage on the busbar not rising;
- and
- deactivating the pre-charging apparatus and jumping to the determining whether there is a fault;
- otherwise:
- waiting to close the electrical switch;
- closing the electrical switch;
- activating a control unit for a switch-on transient;
- and
- jumping to the determining whether there is a fault.
Dependencies are inferred from the claim text.