efficient fault management using remote fault indicators

Prague, 8-11 June 2009

Efficient Fault Management using Remote Fault Indicators

Dr. Eilert BjerkanNortroll AS

Eilert Bjerkan, Nortroll AS-Norway Session 3 Paper 0642


Contents:

• Introduction• Detection Methods• Advantages with Remote Fault Indicators

(Remote FPIs)• Communication options• Summary and conclusions



Introduction:


60/20 kVTransmission

system

Gateway

SCADA System

I0<

I0<I0<

I0<


Introduction:• Electronic FPIs since late 70’s

• Mixed experience with FPIs due to:– Incorrect settings– Inflexibility– Suitability– Incorrect installation– Variable product quality



Increasing requirements toQuality of Supply

SMARTGRIDS



Fault types• I<<: Phase to Phase Faults

(Overcurrent)

• I0<: Cross-country Faults(Double Earth-faults)

• EF: Phase to ground faults(Earth faults)

• DBC: Downed or Broken Conductors.Eilert Bjerkan, Nortroll AS-Norway Session 3 Paper 0642


Detection Methods• Ammetric detection (Current treshold non-directional)

– Absolute treshold– dI/dt (rapid increase relative to load current)– Proportional treshold (relative to load current)

• Transient detection (zero sequence transients I0/U0)• Wattmetric detection (zero sequence 50Hz I0/U0)• Negative Sequence (DBC)• Differential Methods (combined methods and

synchronized measurements)



Distributed Generation and meshed networks

• Traditional FPI methods may fail to detect faults in such networks.

• Possible solutions:– Transient method could be an alternative for Eartfaults.– Automated Intertripping– Reclosing counter – Differential measurements– Directional 50 Hz principles



Remote FPI Live Test Example• Live test of Remote FPIs in compensated 22 kV network in

Ireland (ESB Networks)

• 12 Directional FPIs (DFIs) with remote comms.

• SMS-based Remote Communication to SCADA-system

• 6 Phase-to-ground fault tests successfully detected.

• Detailed localization in very short time



The Remote FPI




Fault Location



Communication alternatives1. Relay interface (cable to RTU)2. Short range radio to RTU or Hub/Concentrator3. Serial bus/communication to RTU or Hub/Conc.

4. GSM/GPRS Communication5. Trunked radio systems for long distance comm.6. Others: Fiber, Twisted Pair, PowerLine, ++

Key topic for FPI integration in active networks:SCADA-integration: IEC870, DNP3


Summary and Conclusions:• Remote FPIs increase operational efficiency:

– Reduce localization and sectionalisation time– Reduce need for manual fault tracking.

• RFPIs– Redundancy (Easier localization)– Less crew intensive– Less time consuming– Enable active networks and cost efficient remote

measurements also in DG/meshed networks.



Thank you for your attention!

Questions or comments?



Extra slides


Uo

Io

Directonal Fault Detection• Transient phase comparison for earthfault detection


FUSE

TRANSFORMER 230V

SURGE ARRESTOR

The IntelligentFault Current Indicator

DOWNEDCONDUCTORDETECTOR

WITH COMM.

BACKFED FAULTFROM DISTRIBUTION

TRANSFORMER

FEEDINGDIRECTION

Th e Intelli gentFa ult Current Indi cator

FAULTLOCATION

NODETECTION

Detection of downed/broken conductors

DETECTION Relay Protection LT 3200

Backfed Fault Rarely Yes

Broken Loops No Yes

Ice/pavement etc. No Yes

Stolen cond. No Yes

Blown HV-fuses No Yes


Remoteswitch

SCADA operating centre

COMTROLL Communication unit

N ORT ROLL GA TEW A Y

R UN

MS G2

TX /RX

U AR T

R ESET

N ORT ROLL GA TEW A Y

R UN

M S G2

TX /RX

U AR T

R ESET

Activateddetector

Downed or brokenconductor

Detection of downed conductors


Cross country faults

60/20 kVTransmission

system

OC CCF EF

FPIs are able to differentiate between Overcurrents (OC) and Cross-country faults (CCF) by means of zero-sequence measurements.

With directional EF-detection both locations can be pinpointed.


Cross country faults

FPIs are able to differentiate between Overcurrents (OC) and Cross-country faults (CCF) by means of zero-sequence measurements.

With directional EF-detection both locations can be pinpointed.


FPI retrofit examples


FPI Factory mounted examples


GSM/GPRS-enabled FPIs

GSM Data / SMS / GPRS

GSM Gateway

NetTroll SCADA System

Short Range RadioCollectorGPRS RTU

Alarms

FPIGSMModem

efficient fault management using remote fault indicators

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