220KV EHV NETWORK AT RELIANCE JAMNAGAR ...cigreindia.org/VIVANTAFEB2017/Data/13-10-17/12.pdfRELIANCE...
Transcript of 220KV EHV NETWORK AT RELIANCE JAMNAGAR ...cigreindia.org/VIVANTAFEB2017/Data/13-10-17/12.pdfRELIANCE...
2. DESIGN
2A. NETWORK:
220 KV NETWORK DESIGN IS DESIGNED WITH 100% REDUNDANCY FROM 220 KV BUS TO LOAD.
THIS IS ACHIEVED WITH DUAL 220 & 33 KV BUSBARS, DUAL 220 AND 33 KV TRANSFORMERS AND
DUAL 220 & 33 KV CABLE NETWORKS.
2B: 220 KV CABLE DESIGN
TWO TYPES OF CABLE CIRCUITS WERE IDENTIFIED TO CATER TO THE NETWORK
TYPE -1-174 MVA CAPABILITY: SINGLE CORE 400SQ.MM XLPE COPPER CONDUCTOR CABLE ISSELECTED TO LAY IN FLAT FORMATION.
TYPE-2- 300MVA CAPABILITY: SINGLE CORE 1000SQ.MM XLPE COPPER CONDUCTOR CABLE IS SELECTED TO LAY IN FLAT FORMATION.
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CABLE SHEATH: LEAD SHEATH IS USED TO PROTECT THE CABLE INSULATION FROM SOLVENTS PRESENT IN THEUNDERGROUND SOIL IN THE REFINERY AND PETROCHEMICAL COMPLEX.
CABLE DESIGN PARAMETERS:
CABLE 400SQ.MM CABLE 1000SQ.MM CABLE
CONDUCTOR COPPER COPPER
INSULATION XLPE XLPE
METALLIC SHEATH LEAD ALLOY LEAD ALLOY
METALLIC SHEATH THICKNESS 1.9MM 2.0MM
OVERALL DIAMETER 97MM 108MM
WEIGHT 16.6 KG/M
CABLES LAID QUANTITY OF 400&1000SQ.MM 140KM
TRENCHES LAID 24KM
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EXECUTION
AT CRITICAL LOCATIONS WHERE VEHICLE MOVEMENT CANNOT BE STOPPED AND AT THE SAMETIME DUCTING WORK WAS SUPPOSED TO BE CARRIED OUT, HDD (HORIZONTAL DIRECTIONDRILLING) METHOD WAS ENVISAGED. DURING HDD JOB SOIL STRATA WAS NOT CONDUCIVE DUETO SOLID ROCK BELOW 1METER OF THE SURFACE AND DUE TO WHICH DRILL FAILED AT SEVERALINSTANCES.
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SITE ACCEPTANCE TESTS
ONCE ALL THE CABLE IS LAID THE CABLE IS TESTED WITH ALL ACCEPTANCE PROCEDURES TOSUCCESSFULLY CHARGE THE CABLE AS PER VENDOR GUIDELINES AND IEC
INSULATION RESISTANCE TEST
DC CONDUCTOR RESISTANCE TEST
LINK BOX CONTACT RESISTANCE TEST:
SVL INSULATION TEST:
DC JACKET TEST:
24 HR. SOAK TEST: THIS TEST WAS PERFORMED TO ENSURE THAT THE CABLE LAID AND CHARGED
ON NO LOAD IS FREE FROM ALL DEFECTS
PARTIAL DISCHARGE MEASUREMENT TEST: CAPACTIVE TYPE PD MEASUREMENT SYSTEM IS
BEING USED
CASE STUDIES: CASE STUDY-1
220KV CABLE INTERCONNECTED BETWEEN 220KV GIS MRS 4 AND C2 COMPLEX MRS-1 WAS
TRIPPED AFTER WAS SUCCESSFULLY CHARGED IN JULY’16
THE CABLE FAULT COULD NOT BE LOCATED EVEN WITH 33KV CABLE FAULT LOCATOR. CABLE WAS
TESTED BY KEEPING 2X105MVA POWER TRANSFORMER IN SERIES HAVING AN IMPEDANCE VALUE
OF 13.25% AND THEREBY LIMITING THE FAULT CURRENT TO 1KA.
NO. OF TIMES SUCH TESTING WAS CARRIED OUT, BUT CABLE IR VALUE IS FOUND NORMAL. LATER
IT WAS DECIDED TO DISCONNECT THE CABLE FROM GIS TERMINATION AND TEST THE CABLE WITH
SWITCH ON TO FAULT LOCATION.
LATER THE FAULT WAS FOUND IN GIS AND WAS VT FAILURE SIEMENS SENT VT TO WORKS
IMMEDIATELY FOR INVESTIGATION. TRACKING WAS VISIBLE ON THE EPOXY GAS TIGHT BUSHING
INSIDE VT TANK. UPON RELIANCE INSTRUCTIONS HV TEST WAS PERFORMED ON THE SAME.
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CASE STUDY-2:
ROUTE-3 1000SQ.MM CABLE RUNNING FROM DTA MRS4 TO C2 MRS-1 CABLE TRIPPED ON JUNE16,
2HOURS AFTER CHARGING.
CABLE FAULT WAS LOCATED WITH THE HELP OF CABLE FAULT LOCATOR AND WAS 58M AWAY FROM ONE
OF THE JUNCTION IN SINGLE (RED) PHASE FROM MRS4.
SITE INSPECTION REVEALED PHYSICAL DAMAGE TO THE CABLE.
A SHARP PHYSICAL DAMAGE WAS ALSO OBSERVED ON THE INSULATION.
FURTHER TO THIS INCIDENT ALL THE METALLIC SHOVELS WERE REPLACED WITH PLASTIC TO AVOID PHYSICAL
DAMAGE TO THE CABLE
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CASE STUDY-3
CABLE DIAMETER DIAMETER OVER
INSULATION
STRESS CONE
RECEIVED AT SITE
NEW STRESS CONE
ENVISAGED
1000 SQ.MM 83.9MM 76.5MM TO 81.5MM 81MM TO 85.5MM
400 SQ.MM 74.1MM 67.5MM TO 72.5MM 72MM TO 75MM
400 SQ.MM WITH DIAMETER OVER INSULATION BEING 74.1MM AND 1000 SQ.MM CABLE WITH
DIAMETER OVER INSULATION 83.9MM.
STRESS CONE USED AS A PART OF 220KV GIS CABLE TERMINATION DID NOT MATCH WITH THE
DIAMETER OF THE CABLE RECEIVED AT SITE. STRESS CONE SUPPLIED
FOR 400SQ.MM VARIED BETWEEN 76.5MM-81.5MM WHICH WAS NOT SUITABLE TO THE CABLE
SUPPLIED.
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CASE STUDY 4
CABLE BETWEEN STG TRANSFORMER AND 220KV GIS WAS CHARGED IN THE MONTH OF
MAY 17.
MINOR SPARK NEAR SUPPORT CLAMP AT THE TIME OF CLOSING THE BREAKER TO
ENERGIZE THE CABLE.
MANUFACTURER PERFORMED SWITCHING OVERVOLTAGE STUDY TO INVESTIGATE THE
TRANSIENT STATE ASSOCIATED WITH THE ROUTE. BY EMTP SIMULATION APPROXIMATELY
THE INDUCED VOLTAGE ONTO THE SURFACE OF THE CABLE WAS 300-600V. THIS SURFACE
VOLTAGE OF CABLE RESULTED IN SPARK PHENOMENA BETWEEN CABLE
THE INSULATOR/RUBBER CUSHION IN BETWEEN CABLE CLEAT AND CLAMP HAS NOT BEEN
PROPERLY LOCATED TO INSULATE THE CABLE FROM THE CLAMP
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SAT WITH EHV TEST KIT
RELIANCE PROCURED THE DAC 300 MEGGER KIT TO TEST EHV CABLES AS SOAK TEST IS GETTING DIFFICULT
DUE TO RELIABILITY OF THE NETWORK.
THE SELECTION OF THIS TEST KIT IS MAINLY DUE TO PORTABLE IN NATURE AND PD TESTING IS POSSIBLE.
HV TEST KIT IS COMMISSIONED IN AUGUST 2017.)
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TEST KIT INSIDE GIS
TEST KIT OUTDOOR
MAINTENANCE PROCEDURES LAID FOR RELIABLE OPERATION.:
THE 220KV CABLE NETWORK LAID ACROSS THE PLANT IS THE HEART OF THE PROJECT AND ANY
HINDRANCE TO THE POWER SUPPLY SHALL HAVE HUGE FINANCIAL EFFECTS TO THE PLANTS
DEPENDING ON THIS NETWORK. SO PREVENTIVE MAINTENANCE IS ONLY SOLUTION TO AVOID ANY
SHUTDOWNS.
FOLLOWING IS THE SUMMARY OF MAINTENANCE ACTIVITIES PERFORMED.
SR. NO. ACTIVITY DETAIL OF ACTIVITY FREQUENCY
1 ROUTE SURVEY
UNDERGROUND: LOOK FOR ANY EXCAVATION JOBS (MANUAL/MECHANIZED) NEAR TRENCHES, STORAGE OF MATERIALS OVER CABLE TRENCH, CONDITION OF ROUTE MARKERS, EXPOSURE OF CABLE TILES DUE TO SOIL EROSION DURING MONSOON.ABOVE GROUND: THIS IS A PATROL CHECK ALONG WHOLE CABLE ROUTE LINE EXPOSED IN THE AIR TO INVESTIGATE CONDITION OF CABLE AND SURROUNDING CONDITION OF ROUTE TO ASSESS PHYSICAL DAMAGE, ARCING OR TRACKING TRACES.
WEEKLY
2 THERMOGRAPHIC INSPECTIONS ONLINE: THERMOGRAPHY TO BE CARRIED OUT FOR AIS END TERMINATIONS AND SUPPORT STRUCTURE/TRAYS FOR IDENTIFYING LOCAL HEATING.
26 WEEKS
3PARTIAL DISCHARGE (PD) MEASUREMENT
ONLINE: MEASUREMENT OF PARTIAL DISCHARGES TO THE RATED OPERATING VOLTAGE USING PD SENSORS.
OFFLINE: MEASUREMENT OF PARTIAL DISCHARGE USING EXTERNAL VOLTAGE SOURCE BY MEGGER DAC 300.
26 WEEKS
5 YEARS
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4SHEATH CURRENT MEASUREMENT
ONLINE: MEASUREMENT OF SHEATH CIRCULATING CURRENT, TO ASSESS HEALTHINESS. THIS MEASUREMENT WILL REVEAL SHEATH PROBLEMS LIKE EXTERNAL DAMAGE OR PIN HOLES IN OUTER SHEATH.
52 WEEKS
5 LINK BOX INSPECTION
OFFLINE: LINK CONTACT RESISTANCE, VISUAL INSPECTION OF LINK BOX FOR MOISTURE INGRESS, CORROSION, ARCING TRACE ETC.
5 YEARS
6 EARTHING SYSTEM INSPECTION
ONLINE: MEASUREMENT OF SCREEN CURRENTS INSINGLE POLE EARTHING CABLES IN TERMINATIONSAIS/GIS
OFFLINE: BONDING INSPECTION, OVER SHEATH TEST, SVL TEST, MEASUREMENT OF EARTHING RESISTANCE, CONTINUITY TEST IN EARTHING CABLES
3 MONTHS
5 YEARS
7 PD BOX INSPECTIONOFFLINE: INSPECTION OF PD BOX FOR MOISTURE INGRESS, CORROSION, ARCING TRACE ETC.
5 YEARS
8SHEATH VOLTAGE LIMITER(SVL) PERFORMANCE CHECK
OFFLINE: VISUAL INSPECTION 5 YEARS
9CORONA MEASUREMENT ON OUTDOOR TERMINATION
ONLINE: TO DETECT INSULATION SYSTEM FOR OUTDOOR TERMINATIONS AND SURROUNDINGS WITH CORONA CAMERA
26 WEEKS
10HARMONIC CURRENT MEASUREMENT
ONLINE: MEASUREMENT OF HARMONIC CURRENT WITH POWER ANALYSER
52 WEEKS
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MAINTENANCE PROCEDURES LAID FOR RELIABLE OPERATION.:
11INSULATION RESISTANCE OF OUTER SHEATH
OFFLINE: IR VALUE OF SHEATH TO BE MEASURED USING DC VOLTAGE TEST.THIS IS TO BE DONE ALONG WITH OFFLINE HIGH VOLTAGE TESTING AND PD MEASUREMENT.
5 YEARS
12 HIGH VOLTAGE TESTINGOFFLINE: HIGH VOLTAGE TESTING TO BE CARRIED OUT BY USING EXTERNAL VOLTAGE SOURCE MEGGER DAC 300
5 YEARS
13INSPECTION OF CONNECTION POINT
OFFLINE: INSPECTION OF CONNECTION POINT FOR AIS TERMINATIONS TO BE CARRIED OUT FOR IDENTIFYING OVERHEATING OR CORROSION ON CONNECTION POINT OF CABLES.
5 YEARS
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MAINTENANCE PROCEDURES LAID FOR RELIABLE OPERATION.: