Dc Earth Fault Locator 2n604h

Taurus Powertronics – Presentation WELCOME TO ALL TANTRANSCO OFFICIALS

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Comprehensive Bouquet of Product Offline Overhead Transmission Line Analyser System

Offline Overhead HVDC Line Analyser System Offline Overhead Distribution Line Analyser System DC Earth Fault Locator Tower Footing Earth Impedance Tester Earth Tester Insulation Analyser upto 30kV Corona Imaging Camera SF6 Gas Leak Detector Taurus Confidential Document

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DC Earth Fault Locator

Application: •

To Locate Earth Faults / Earth leakages in floating DC system of a power station.

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DC Floating System In Generation and Transmission substations the

entire system of the DC Source along with connecting cables, battery charger and control equipment forms DC floating system i.e. at no point it is electrically connected to earth.

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Problems with Earth fault on a DC Floating System

In case of a earth fault either in positive or negative

due to a cable damage or insulation failure the entire control system gets electrically connected to earth and no more remains a floating system  Further, a fault happening to this earthed system in the opposite polarity results in overloading of DC source, which results in cable burning and disruption of power to the control equipment and also malfunctioning of DC System may occur.

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Healthy DC System single line Diagram

X k LOAD

BATTERY

CHARGER

X k

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DC System with Positive fault

Y k

Battery

Charger

Load

X k X k

Equivalent CKT Y k LOAD

Battery

X k

Charger X k

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DC System with Negative fault X k Battery

Load

Charger X k

Y k

Equivalent CKT X k Load

Battery

Charger Y k

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X k

Principle of Operation Injects low frequency coded pulses into the DCDB

main bus. Injected signal is traced using receiver unit. Once there is a ground fault, the injected signals will get a closed loop to the transmitter ground through fault ground The systematic approach of noting where pulses have been detected, then moving down the feeder up to the point where pulses are not detected, pinpoints the ground fault location. Taurus Confidential Document

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DC Earth Fault Locator along with accessories

Transmitter Unit

15 sq.mm sensor CT

Receiver Unit

50 sq.mm sensor CT

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Two core connecting cable

DCDB Connecting Cable

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Earthing Cable

Connection Diagram Batter y Bank

Negative Bus Connection Positive Bus Connection Station Ground

Charge r

Taurus DC Transmitter Unit Taurus Confidential Document

Fault Indicatio n

Taurus DC Receiver Unit

Faul t 9/5/15

Relay

No Fault Indicatio n

Demo Pic

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Demo Pic

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Demo Pic

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USP/Product Highlights  Online fault finding  Automatic Capacitance Balancing  Multiple fault detection  Detection of point of mixing in dual Battery system  Noise and harmonics suppression  Exactly pin points the fault  Long duration, service free rechargeable battery  Additional filters in Receiver Unit for AC Noise Suppression for

trouble free operation in Generating Station  Complies & certified as per IEC 61000-4-2, IEC 61000-4-3, IEC 61000-4-8, IEC 60068-2-6, IEC 60068-2-27, IEC 60068-2-78  IP67 Protection (Pelican casing)

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Specifications  Resistance Range: Up to 400K Ohms  Suitable for DC floating system from 48 to 300V DC  Sensitivity < 1mA  Output Voltage: Auto selectable  Power Supply: Built in Rechargeable Battery  Sensor probes: 2 nos. of 15 & 50 sg. mm  Fault distance: Up to 3KM.  Input signal: LF/LV Pulse

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s  NTPC  State Generating companies  Private Generating Companies  POWERGRID  State Transmission Companies  private Transmission Companies  Captive Power Plants  Process Industries  Mining Industries  Railways Taurus Confidential Document

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Case Study

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Case Study - 1 Customer: Rourkela Steel Plant. Customer Problem: Problem in 220V system, with voltage conditions as SOURCE

Positive to Ground

Negative to Ground

Positive to Negative

1

0

220

220

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Fault Tracing With our kit, it was found that feeder no.M9 was

having earth fault. Further traced in sub feeder we found Fault in Relay of bay three. But after all these exercises we found no improvement in the voltage. Once again we started with the DCDB and feeder No M10 was showing faulty. After isolating the same system voltage got balanced. SOURCE

Positive to Ground

Negative to Ground

Positive to Negative

1

110

110

220

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Case Study - 2 Customer: JSPL. Demo Place: JSPL, Angul. Customer System Status: SOURCE

Positive to Ground

Negative to Ground

Positive to Negative

1 2

130 130

100 100

230 230

After testing each feeders in both the sources below mentioned

feeders found to be faulty. S-1=2F-A, 5R-C,5R-D and 1R-D. S-2=2F-A,5R-C,5R-D and 1R-E. Customer preferred to switch off the feeders due to lack of coordination with other Team. After Switching them OFF system voltage got balanced. Taurus Confidential Document

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Case Study - 3 Customer: EMCO ENERGY LTD. Demo Place: 600MW Thermal Power Plant, Warora.

Customer System Status: SOURCE

Positive to Ground

Negative to Ground

Positive to Negative

1

0

220

220

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Positive Dead Fault  After testing each feeder for fault, its finally found in

feeder No. 2.4F which was feeding 6.6KV Control .  Feeder C1A of 6.6KV Control found to be faulty.  Tracing further through inside circuitry found insulation damage on the wire connected between Relay and CB.  After improving its insulation with help of a insulation Tape system voltage got balanced. Taurus Confidential Document

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Taurus Confidential Document

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Case Study - 4 Customer – CESC Ltd. Demo Place- 750MW BBGS, Kolkata. Equipment was tested on Unit-3 220V DCDB.

SOURCE

Positive to Ground

Negative to Ground

Positive to Negative

DCDB Unit#3

239

1

240

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Negative Dead Fault  Each feeder was tested for earth fault and fault found

in feeder No’s 14F-B & 14F-D.  Both the above feeders were feeding unit#3 6.6KV Bus Transfer .  And further traced to a ABB make SUE 3000 HMI Unit (A monitoring system).  Visibly able to identify the carbon deposition on the front door display unit (power circuitry).  After replacing it with a new one , system voltage got improved. Taurus Confidential Document

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System Voltage after Fault rectification Unit is replaced with a new one and observed the

improved voltage level.

SOURCE

Positive to Ground

Negative to Ground

Positive to Negative

DCDB Unit#3

124

116

240

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Taurus Confidential Document

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THANK YOU FOR YOUR VALUABLE TIME

FOR APPLICATION Mr. Ganapathy M-Sr.Technical Engineer No:09900046970 Taurus Confidential Document

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