Fault current enhancement for energy resources with power electronic interface
AssigneeABB Schweiz AG
InventorsAndrew Tuckey, Juergen Zimmerman
Life of this patent
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Abstract
The present invention is concerned with a fault current enhancement for triggering a protection device, such as a fuse or circuit breaker or protection relay used in protecting a distribution line of a power distribution network in an efficient and economical way. An Induction Machine (IM) is operated in parallel with an energy source connected to the distribution line via a Power Electronics (PE) interface, to provide a fault current characteristic of the composite PE interface and IM similar to that of a synchronous generator. Comparable fault currents enable a same protection device to be provided for protecting the distribution line irrespective of a kind of interface used to source energy to the distribution line.
Claims25
A power distribution system with a distribution feeder protected by a protection device against a fault occurring downstream of the protection device, and with a first energy source connected via a power electronics interface comprising a converter or an inverter to the distribution feeder upstream of the protection device and causing the protection device to clear the fault within a first fault clearance time,
- wherein the power system comprises an induction machine connected to the distribution feeder upstream of the protection device, and adapted to cause, in particular together with the first energy source connected via the power electronics interface, a fault current in the distribution feeder, said fault current causing the protection device to clear the fault within a second fault clearance time following the fault;
- and
- wherein the induction machine has a first power rating PIM which is at least approximately in the same order of magnitude as a second power rating of the first energy source;
- and
- the induction machine is configured to neither provide a substantial amount of work to any kind of external equipment or machinery, nor to receive any substantial amount of work by any kind of external equipment or machinery, i.e. with an amount of work WIM provided by or to the induction machine being negligible in comparison to the first power rating PIM, i.e. 10WIM<PIM.
A method of operating a power distribution system with a distribution feeder protected by a protection device against a fault occurring downstream of the protection device, and with a first energy source connected via a power electronics interface comprising converters or inverters to the distribution feeder upstream of the protection device, comprising:
- connecting an induction machine to the distribution feeder upstream of the protection device, said induction machine having a first power rating PIM which is at least approximately in the same order of magnitude as a second power rating of the first energy source;
- configuring the induction machine to neither provide a substantial amount of work to any kind of external equipment or machinery, nor to receive any substantial amount of work by any kind of external equipment or machinery, i.e. with an amount of work WIM provided by or to the induction machine being negligible in comparison to the first power rating PIM, i.e. 10WIM<PIM;
- rotating, during regular operation of the power distribution system, a rotor of the induction machine;
- and
- providing, following the fault, a fault current by the induction machine to clear the fault.
Dependencies are inferred from the claim text.