Post on 04-Jan-2017
Prashant Das Tauruspowertronics Pvt. Ltd
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CIGRE INDIA
1
Transmission lines
Prashant Das Tauruspowertronics Pvt. Ltd
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• Transmission lines constitute more than 60% of asset of power transmission.
• They traverse an incredible range of kilometer in harsh environments, climates and terrains.
• In India many of the Transmission lines currently in service were built in the 1960s and 70s and are subject to many problems including ageing.
• With growing demands, there is huge expectations from transmission companies to keep the transmission line uptime near to 100%.
• Hence accurate fault location, health check / monitoring the same is very much essential.
Type of common faults in overhead Transmission lines
Prashant Das Tauruspowertronics Pvt. Ltd
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All Types of Open & Short Category faults
Overhead Transmissionline fault locator & Analyzer
Prashant Das Tauruspowertronics Pvt. Ltd
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• Pre-Commissioning Check of EHV Lines –Continuity, Phase Sequence, line length verification.
• Ascertaining line healthiness before re-Charging.
• For Preventive & Predictive Maintenance of existing EHV Lines.
• Restore the EHV lines ASAP to maintain UP TIME.
Fault Locator and types of fault locator
Prashant Das Tauruspowertronics Pvt. Ltd
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OVER HEADTRANSMISSIONLINE FAULT LOCATOR (OHFL)
• Online• Offline
5
OHFLBasic Principals of working
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• ONLINE-Systems works on the principal of powersystem Parameters & Data is taken during stressedbreakdown condition and this data is in percentageaccuracy depending on the residual impedance ofthe line.
• OFFLINE-Systems works on the principal of Multiplepulse Eco Co-relation technique & doesn't requireany input parameters for accurate fault finding.
Online method some of it’s limitations
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• Each Line require one dedicated equipment.
• It is not helpful for spur lines.• Open Circuit faults can’t locate through
online systems.• Fault locating accuracy may vary in
percentage. (+/_ 10% or more)• Pre-Commissioning tests are not possible.
Offline method
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• Advanced high frequency multiple pulseco-relation technique
• How it works:- High frequency Coded pulse sent in to
the powerline- picks up different types of disturbance
and location- Information Decoded- Generates User Friendly Report and gives
complete vision of the line end to end
Offline methods and it’s advantages
Prashant Das Tauruspowertronics Pvt. Ltd
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• It’ is accurate up to +/- 100Mtr.• One equipment is enough for whole sub station.• It can be used for Spur line fault locating.• Pre –Commissioning tests are possible.• Offline system can identify the secondary faults
before re charging the line.• It can find out Open Circuit faults.• Does not require any complimentary system at other
end of the sub station.• It can Locate faults up to 2500KM.
Offline OHFL Diagnostic outputs
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• Fault Locator(Breakdown): For finding the faults at accurate distance.
• Line Signature Analysis: for understanding the healthiness of the line.
Overhead transmission
line fault locator benefits
Prashant Das Tauruspowertronics Pvt. Ltd
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• Apart from finding dead faults , useful for predictive and preventive maintenance-
i) It can detect developing faults .ii) It can detect nature of the fault(Open/Short)iii) It can indicate severity of the fault (Level of the
Faults).
• Less time to find faults and its location. • Healthiness check up for the entire line .
Case Studies
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• Short circuit Fault• De-capping• All jumpers not through in Quad line• Leaky Insulators• Clearance related problems• High frequency effects on transmission lines
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission lines
Prashant Das Tauruspowertronics Pvt. Ltd
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SHORT CIRCUIT FAULT at 112 KM
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 14
Decapping Fault at 69 Km in B Phase
Decapping
Fault
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 15
ALL JUMPERS NOT THROUGH AT 55 KM
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 16
Corona due to loose jumper
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 17
SIGNATURE AFTER THROUGH JUMPER
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 18
Flashover insulator at 5.8 and 5.3 KM
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 19
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 20
Trees very close to Transmission Line in B-phase
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 21
After Removal of trees
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 22
• Line Signature Analyser could identify the stress of the linecaused by high frequency noise flowing on the surface ofinsulators and flashover.
• Line Signature Analyser printout with and without filtersreveal the presence of several kV’s of high frequency noiseand really a cause for flash over of insulators
• The noise was later found due to parallel HVDC lines andthyristor switching action
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 23
Annexure –A without filterPadghe – BBLR – gain 1 without filter-Lots of noise
CASE STUDIES
Short circuit FaultDe-cappingAll jumpers not through in Quad lineLeaky InsulatorsClearance related problemsHigh frequency effects on transmission linesPrashant Das Tauruspowertronics Pvt. Ltd
prashant.das@tauruspowertronics.com www.tauruspowertronics.com 24
Annexure – B with HVDC filterPadghe – BBLR– Gain1 No noise observed
CASE STUDIES
OFFLINE OVERHEAD LINE FAULT LOCATOR
Prashant Das Tauruspowertronics Pvt. Ltd
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Case Studies of 25 lines taken in a Transmission ZONE during 2011-2012 . Statistics are based on the OnM internal record maintained for 365 days
Line Lengths in
KMs
Without OHFL time
taken to rectify the fault in a line (Hrs)
With OHFL time
taken to rectify
fault in a line (Hrs)
No. Of Lines in
the Zone (Total
Sample 25 lines)
Average No. of
Tripping in a
Year/Line
Total Trippings in a Year
Ideally with OHFLtime
would have taken
OHFL used
at
Time taken to
find fault with
OHFL in ( Hrs)
OHFL not
used
Time taken to find fault in
HRS without
OHFL (Hrs)
Total
time take
n
EXTRA HOUR
S
0 to 150 KMs
15 3 19 3 57171 hrs
30 places
90 hrs
27 places
405 hrs
495 hrs
324 hrs
150 to 250 Kms
19 4 4 2 832 hrs
5 Places
20 hrs
3 Places
95 hrs
115 hrs
83 hrs
250 to 350 Kms
23 4 2 2 416 hrs
1 places
4 hrs
1 place
23 hrs
27 hrs
11 hrs
Case Studies
OFFLINE OHFL
Line Signature
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Case Studies of 73 new lines in a Utility Transmission company in India
KV of the line No.of LinesNo of Tripping Without Line
Signature test
No.of Lines signature test was done
No. of lines successfully charged
after Signature Analyzer
132KV 5 3 3 3
220KV 20 11 9 9
400KV 40 16 14 14
765KV 8 3 3 3
Important parameters-while choosing an overheadtransmis
sion line fault locator
Prashant Das Tauruspowertronics Pvt. Ltd
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• Equipment should be Portable & Battery operated. • Induction Voltage Suppression capability.• Auto Impedance matching facility for the kit to be
used in any EHV Lines.• Instrument should be EMI/EMC Compliance.
PAPER
Presented by
POWERGRID IN CBIP – INTERNATIONAL CONFERENCE
Using Offline Fault Locator
TO DIAGNOSE THE TRANSMISSION LINE
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Thank you for
your attendan
ce
Prashant Das Tauruspowertronics Pvt. Ltd
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For more information Write to :
PRASHANT DAS
prashant.das@tauruspowertronics.com
+91 9766355355