Distribution Grid Automation with Fault Detectors

Local Fault Indication

In radial networks without communication, local indication can be employed to find the fault. The detectors indicate a fault current using a local LED (flashing LED; red or green). The stations “upstream the fault” are flashing red, while those “downstream the fault” flash green. The repair personnel can thereby easily and fast localize the fault on the cable.

RTU Function for IEC 60870-5-101/104

Så fort kommunikation finns tillgänglig via standardprotokollen
​​​​​​​IEC 60870-5-101 eller -104 är det möjligt att skicka feldetektorns indikeringar till driftcentralen.

Med en uppkopplad nätstation finns det även möjlighet att samla in indikeringar från frånskiljare/effektbrytare, och en IPC har utgångar som direkt kan styra dessa apparater. För en låg tilläggskostnad har man en helt fjärrstyrd nätstation!

Time Selective Disconnection of Faults

Detta är en typisk situation vid radiella nät. The secondary substations are supplied with fault detectors of type IPS2, where the fault indication can be shown visually (flashing LED) or with closing contact (or both).

In strategically selected stations with circuit breakers,
IPS2 can disconnect downstream faults.

The diagram to the right illustrates when the different IPS2 units operate (in this case with time selectivity). Note that with a pre-charged spring you need no auxiliary power at the secondary substation. IPS2 has a backup via super capacitors or external batteries, and the trip relay uses 230 VAC from the low voltage side of the transformer.

"Bright" Power Restoration

Option for IPC4011
When a fault occurs in the loop, the respective IPC unit will send information if the fault has passed (earth fault or overcurrent), both to the dispatch centre via remote protocol and to the nearest IPC unit. This enables automatic power restoration within 200 ms, i.e., so fast that the protection relay in the feeding substation will not operate. The customers will experience only a very short voltage dip (< 0.2 s).

At faults downstream the radial feeder (top right), IPS2 will trip the outgoing feeder and block the automatic power restoration of the loop.

"Dark" Power Restoration

Option for IPC4010 and IPC4011
Function similar to "Bright" Power Restoration (see previous example). In this application disconnectors are used instead of circuit breakers, requiring that fault disconnection and power restoration is made when the loop is disconnected from the distribution substation.

IPC4011 with Power Restoration

Art.no 101131-002
An IPC4011 is required in every secondary substation where there is a need to detect earth faults or short circuits. Circuit breakers are not needed in each seconary substation where detection is desired, it is possible to configure the detector so that does not participate in the power restoration sequence.

IPC4011 can be configurered for "Bright" or "Dark" type of power restoration.

IPC4010 with Power Restoration

Art.no 101130-002