BHARAT HEAVY ELECTRICALS LIMITED
BHARAT HEAVY ELECTRICALS LIMITED
AN OVERVIEW
BHARAT HEAVY ELECTRICALS LIMITED
AN OVERVIEW
BHARAT HEAVY ELECTRICALS LIMITED
SOME FACTS ¾ TOTAL ¾ 71
INSTALLED CAPACITY OF INDIA IS 106254.22 MW
% OF THE TOTAL ELECTRIC ENERGY GENERATED BY COAL
SETS IN THE COUNTRY WAS CONTRIBUTED BY 210 / 250 / 500 MW RATING BHEL SETS THOUGH THEY FORM 63 % OF TOTAL GENERATING CAPACITY OF THE COUNTRY ¾ MORE
THAN 60 % OF THE THERMAL MACHINES OPERATING IN
INDIA ARE OF KWU DESIGN. ¾ HIGH
RELIABILITY,AVAILABILITY,BETTER HEAT RATE, FASTER
START UP AND SHUT DOWN,MAINTENANCE FRIENDLY ENABLES HIGHER ACCEPTABILITY AMONGST MOST CUSTOMERS IN INDIA. ¾ KWU
TECHNOLOGY HAS WEATHERED IN INDIAN CONDITIONS
AND CUSTOMER HAS SHOWN CONFIDENCE BY PLACING REPEAT ORDERS
BHARAT HEAVY ELECTRICALS LIMITED
PLANT LOAD FACTOR AND OPERATIONAL AVAILABILITY OF SOME NTPC MACHINES
BHARAT HEAVY ELECTRICALS LIMITED 1999-2000
2000-2001
2001-2002
2002-2003
2003-2004
PLF
OA
PLF
OA
PLF
OA
PLF
OA
PLF
OA
UNIT-1
98.9
96.5
96.6
94.4
97.3
97.0
95.3
95.6
100.1
98.2
UNIT-2
93.1
93.0
98.6
97.7
93.0
93.9
96.9
98.2
99.3
98.7
UNIT-3
83.7
83.7
98.7
98.1
78.2
78.2
93.5
95.0
97.1
97.3
UNIT-4
93.8
93.4
87.8
88.4
68.4
68.5
96.0
97.3
98.1
97.4
UNIT-5
96.5
97.8
97.6
96.7
91.2
92.9
89.2
91.3
98.2
98.1
UNIT-6
92.7
92.7
91.9
92.1
92.6
95.7
84.9
90.0
82.6
87.2
UNIT-7
95.6
95.8
91.0
92.8
89.5
90.6
95.9
97.8
76.7
78.8
UNIT-1
84.4
85.3
96.6
97.1
93.2
94.1
94.1
94.2
94.2
93.7
UNIT-2
93.5
94.0
97.5
97.8
90.4
91.4
94.0
93.9
94.7
94.2
UNIT-3
91.4
93.5
95.6
95.9
93.5
94.6
92.9
93.8
89.0
89.6
UNIT-4
82.4
86.7
79.0
84.5
91.2
93.7
89.0
93.3
89.1
93.9
UNIT-5
83.7
87.1
89.6
93.3
87.5
89.3
87.4
92.0
89.1
94.2
UNIT-6
85.6
88.8
86.6
90.2
89.8
92.8
87.1
92.7
82.7
86.7
PLANT/YEAR
SINGRAULI
KORBA
BHARAT HEAVY ELECTRICALS LIMITED 1999-2000
2000-2001
2001-2002
PLF
OA
PLF
OA
PLF
OA
PLF
OA
PLF
OA
UNIT-7
-
-
75.8
84.5
60.0
68.0
88.8
92.0
88.1
93.5
UNIT-8
-
-
80.8
88.4
79.0
82.3
87.4
90.3
74.2
77.7
UNIT-1
-
-
-
-
-
-
85.3
88.3
84.2
87.1
UNIT-2
-
-
-
-
-
-
92.4
96.5
91.6
94.7
UNIT-1
96.6
96.3
97.2
97.1
88.4
92.1
86.6
95.1
84.3
94.4
UNIT-2
97.0
96.6
95.7
97.1
94.2
98.4
80.8
90.0
86.1
95.4
UNIT-3
96.7
97.2
90.2
91.9
90.7
95.6
82.6
93.6
84.2
93.1
UNIT-4
94.3
94.6
91.2
91.8
89.5
94.8
78.4
87.7
81.3
90.1
UNIT-4
87.1
90.3
84.6
85.7
87.9
90.8
88.5
89.8
88.6
91.8
UNIT-5
91.4
92.2
91.5
92.2
86.8
89.2
93.2
94.3
83.7
85.6
UNIT-6
90.2
89.3
89.9
90.4
83.0
84.9
92.3
93.4
91.5
92.7
UNIT-4
71.7
82.3
91.5
95.7
81.6
86.6
85.8
92.4
92.8
99.4
UNIT-5
82.5
92.8
69.1
76.0
89.3
99.2
87.4
92.8
90.3
96.4
PLANT/YEAR
VINDHYACHAL
SIMHADRI
DADRI
RAMAGUNDAM
BADARPUR
2002-2003
2003-2004
BHARAT HEAVY ELECTRICALS LIMITED
AGE WISE ANALYSIS OF KWU DESIGN TURBINES SUPPLIED BY BHEL
BHARAT HEAVY ELECTRICALS LIMITED
AGE-WISE ANALYSIS
500 MW (NR + ER + WR + SR)
250 MW (NR + ER + WR + SR)
210 MW (NR + ER + WR + SR)
< 5 YRS
5 (0 + 1+ 2 + 2)
4 (4 + 0 + 0 + 0)
15 (4 + 3 + 5 + 3)
5 – 10 YRS
2 (0 + 1 + 1 + 0)
4 (0 + 0 + 2 + 2)
21 (3 + 8 + 2+ 8)
10 – 15 YRS
8 (0 + 1 + 4 + 3)
0
31 (11 + 5 + 5 + 10)
15 – 20 YRS
5 (2 + 0 + 3 + 0)
0
29 (6 + 3 + 16 + 4)
20 – 25 YRS
0
0
21 (2 + 2 + 12 + 5)
> 25 YRS
0
0
0
BHARAT HEAVY ELECTRICALS LIMITED
OPERATIONAL PROBLEMS IN KWU TURBINES
BHARAT HEAVY ELECTRICALS LIMITED
A.
LP BLADE FAILURE
B.
BARRING GEAR STOPPAGE
C.
HIGH HP FRONT SHAFT VIBRATION
D.
LOW VACUUM DUE TO HIGH AIR INGRESS
BHARAT HEAVY ELECTRICALS LIMITED
LP BLADE FAILURE
BHARAT HEAVY ELECTRICALS LIMITED
LP BLADE FAILURE :- PROBABLE REASONS ¾
POOR WATER CHEMISTRY
¾
OVERLOADING OF TURBINE
¾
OFF FREQUENCY OPERATION
¾
ALTERATION OF NATURAL FREQUENCY DUE TO EROSION OF BLADE (OPERATION WITH LOW STEAM PARAMETER & VWO OPERATION)
¾
LOW VACUUM / HIGH EXHAUST HOOD TEMPERATURE
¾
MECHANICAL RUBBING DUE TO BAD CENTERING
¾
STAGNATION OF WATER IN LP EXTRACTION –1
¾
POOR MACHINING OF BLADE ROOTS / GROOVES
¾
LP WATER INJECTION SYSTEM
¾
POOR MATERIAL OF BLADES
BHARAT HEAVY ELECTRICALS LIMITED
LP BLADE FAILURE :- RECOMMENDATIONS / ACTION TAKEN ¾
CONDUCTANCE OF MPI / NFT FOR HEALTHINESS OF LP FREE STANDING BLADES OF 500 / 250 / 210 MW AFTER FIRST 50,000 OPERATING HOURS TO BE CONTINUED
¾
CARE TO BE TAKEN DURING O&M OF THE PLANT Avoid following operation ¾Off
– Frequency operation
¾Full
load operation with low vacuum
¾Prolonged
no load operation
¾Overloading ¾Continuous
Valve Wide Open operation
Ensure the proper functioning of following systems ¾Turbine
Drainage System
¾LP
heaters Drip Cascading auto controls and LP heaters level alarm system
¾LP
exhaust hood spray system
¾Protection ¾Water
System to avoid incidence of overspeeding, motoring etc.
chemistry regime
BHARAT HEAVY ELECTRICALS LIMITED
LP BLADE FAILURE :- RECOMMENDATIONS / ACTION TAKEN ¾
ADDITIONAL CHECKS TO BE CARRIED DURING OVERHAULING OF LP MODULE ¾ Centering
Check (Record for any rubbing / touching marks at LP casing
and LP blade tips) ¾ Replacement
of badly eroded LP blades.
¾ Chemical
Analysis of salt deposits on LP blades, if any, by customer.
¾ Servicing
/ inspection of LP exhaust hood spray nozzle to be included in LP
module overhaul.
BHARAT HEAVY ELECTRICALS LIMITED
BARRING GEAR STOPPAGE
BHARAT HEAVY ELECTRICALS LIMITED
BARRING GEAR STOPPAGE : PROBABLE REASONS ¾
FAILURE OF LUBRITE PACKERS / KEYS
¾
MAL OPERATION OF GLAND STEAM SYSTEM
¾
CHANGE IN CENTERING OF LP GLAND BOXES
¾
DAMAGE TO HP / IP CASING INSULATION
¾
IMPROPER ROLL CHECK OF HP/IP AND LP CASINGS
¾
POOR BUMP CHECK
¾
POOR LIFT OF JOURNAL IN BEARINGS
¾
HIGH DIFFERENTIAL TEMP. OF TURBINE CASING
¾
POOR SETTING OF OIL CATCHERS/SEALS
¾
FOREIGN MATTER IN STEAM FLOW PATH
¾
INADEQUATE MOTIVE POWER
¾
EXCESSIVE PIPE PULLS
BHARAT HEAVY ELECTRICALS LIMITED
BARRING GEAR STOPPAGE : RECOMMENDATIONS / ACTION TAKEN ¾
REFER TROUBLE SHOOTING CHART
¾
INTRODUCTION OF MODIFIED GLAND STEAM SYSTEM
¾
FOR CENTERING & ROLL CHECK OF HP & IP TURBINE WITH TIP TO TIP GLAND SEALS REF. TECH. CIRCULAR X-74 DATED 6 TH NOV’2002
¾
ADJUST POOR BUMP CHECK OR CONSULT BHEL
¾
CHECK ROTOR SYSTEM CAN BE ROTATED EASILY BY HAND
¾
CHECK MACHINE COMES TO AUTO BARRING
¾
CHECK SPEED AT FULL BARRING AND COMPARE WITH PROTOCOLS
¾
ENSURE PROPER INSULATION OF HP & IP CASING
¾
REPLACEMENT OF LUBRITE PACKER WITH HIGH TEMPERATURE MODIFIED PACKERS
¾
BELLOWS BEING INTRODUCED IN LP FRONT AND REAR GLAND STEAM SUPPLY AND LEAK OFF LINE
BHARAT HEAVY ELECTRICALS LIMITED
HIGH HP FRONT SHAFT VIBRATION
BHARAT HEAVY ELECTRICALS LIMITED
HIGH HPF SHAFT VIBRATIONS : PROBABLE REASONS ¾
HIGH COUPLING RUNOUT / SWING CHECK
¾
HIGH SLOW ROLL CHECK VALUE
¾
UNEQUAL / DISTORTED RADIAL CLEARANCE
¾
BAD CENTERING / ROLL CHECK
¾
JAMMED SEAL SEGMENTS
¾
ROTOR UNBALANCE
¾
ANY MAJOR WORK DONE ON LP / GEN ROTORS, WHICH MAY HAVE CAUSED ROTOR SYSTEM UNBALANCE
¾
BAD BEARINGS
¾
HIGH ROTOR RUN OUT AT JOURNAL / GLANDS
¾
HIGH RUN-OUT / DENT MARKS AT THE LOCATION OF SHAFT VIBRATION PICK-UP
¾
POOR ALIGNMENT / POOR LOADING OF BEARINGS
¾
OIL WHIRL CONDITIONS
BHARAT HEAVY ELECTRICALS LIMITED
HIGH HPF SHAFT VIBRATIONS : RECOMMENDATIONS / ACTION TAKEN ¾
ANALYSE THE VIBRATION AND OPERATIONAL DATA
¾
CHECK
BEARING
ASSEMBLY,
ALIGNMENT,
COUPLED
RUN
OUT,
ADJUSTMENT OF STEAM PATH ¾
CROSS MATCHING OF HP / IP / LP ROTOR COUPLING FACES AT BHEL WORKS
¾
CHANGE IN THE AXIAL POSITION OF SHAFT VIBRATION PICK-UP DUE TO HIGH SPOTS IN PRESENT LOCATIONS OF PICK UP
¾
SLOW / RATED SPEED BALANCING
¾
ENSURE PROPER FUNCTIONING OF SEAL SEGMENTS
¾
PERIODIC SETTING OF SPRING LOADED TG DECK
¾
INCREASE IN BEARING HEIGHTS, IF OIL WHIRL PRESENT AND BEARING TEMPERATURE DISTRIBUTIONS NOT OK
BHARAT HEAVY ELECTRICALS LIMITED
LOW VACUUM DUE TO HIGH AIR INGRESS
BHARAT HEAVY ELECTRICALS LIMITED
VARIOUS METHOD OF DETECTING AIR INGRESS OFF LINE METHOD
•Water fill test or vacuum tightness test •Steam pressurization test. ON LINE METHOD
• With the help of Helium Leak Detection Instrument
BHARAT HEAVY ELECTRICALS LIMITED
WATER FILL TEST : NEW INITIATIVES / GUIDELINES ¾
RECENTLY, BHEL – HARIDWAR HAS ISSUED GUIDELINES MENTIONING THAT FROM SIMHADRI ONWARDS, ALL CONDENSERS OF 210 / 250 / 500 MW ARE DESIGNED TO WITHSTAND WATER FILL TEST UPTO LP BLADE TIP. THIS WILL HELP IN DETECTING ALL MOST ALL AIR INGRESS POINT
¾
NO
FALL
IN
WATER
LEVEL
IN
24
HOURS
SHALL
INDICATE
SUCCESSFUL COMPLETION OF WATER FILL TEST
¾
IN CASE OF FALL IN LEVEL, HIDDEN AIR INGRESS POINTS NEEDS TO BE TRACED BY ELIMINATION PROCESS.
BHARAT HEAVY ELECTRICALS LIMITED
STEAM PRESSURIZATION TEST ¾
STEAM
PRESSURISATION
TEST
IS
CONDUCTED
TO
FIND
OUT
LEAKAGES IN THOSE AREAS WHICH WILL REMAIN UNDER VACUUM AND NOT COVERED IN WATER FILL TEST / VACUUM TIGHTNESS TEST.
¾
STEAM PRESSURISATION OF VACUUM SYSTEM IS DONE IN AN ABSOLUTELY COLD MACHINE AND PIPING SYSTEM.
¾
STEAM PRESSURIZATION TEST INVOLVES FOLLOWING 3 STEPS: ¾STEP
1 : - CONDUCT WATER FILL TEST AND ENSURE THERE IS NO
FALL IN WATER LEVEL FOR 24 HOURS. ¾STEP
2 :- PREPARATION OF THERMAL SCHEME OF TURBINE FOR
STEAM PRESSURISATION. ¾STEP
3 :- CONDUCT STEAM PRESSURISATION OF VACUUM SYSTEM.
BHARAT HEAVY ELECTRICALS LIMITED
HELIUM LEAK DETECTION TEST : SCHEME FOR DETECTING AIR INGRESS HELIUM GAS SPRAY ON SUSPECTED AIR INGRESS POINTS
VACUUM PUMP
STEAM + AIR
AIR EXHAUST
CONDENSER SAMPLE LINE
HELI LEAK DETECTOR
BHARAT HEAVY ELECTRICALS LIMITED
COMPARISON OF STEAM PRESSURISATION TEST AND HELIUM LEAK DETECTION TEST S.N
STEAM PRESSURISATION TEST
HELIUM LEAK DETECTION TEST
1.
CAN PINPOINT THE SOURCE
CAN DETECT BROAD AIR
OF AIR INGRESS
INGRESS AREA
CAN BE DONE ONLY WHEN
CAN BE DONE AT LOAD
2.
MACHINE IS COLD 3.
REQUIRE STEAM AND WATER
REQUIRES HELIUM GAS WHICH IS NOT READILY AVAILABLE AT MANY POWER STATIONS
4.
REQUIRE SYSTEM
BULKY AND DELICATE
PREPAREDNESS PRIOR TO
INSTRUMENT
CONDUCT THE TEST 5.
SIMPLE PROCEDURE
TEDIOUS EXERCISE
BHARAT HEAVY ELECTRICALS LIMITED
OTHER PROBLEMS FACED IN KWU MACHINES ¾
HIGH AXIAL SHIFT / DIFFERENTIAL EXPANSION
¾
MS / HRH STRAINER CHOKING
¾
OIL STARVATION
¾
OVERSPEEDING OF TURBINE
BHARAT HEAVY ELECTRICALS LIMITED
BHEL’S VIEW ON SPRING LOADED FOUNDATION
BHARAT HEAVY ELECTRICALS LIMITED
SPRING LOADED TG DECK : ADVANTAGES ¾
MAJOR CORRECTION IN CATENARY OF MACHINE BY
ADJUSTMENT
OF SHIM PROVIDED IN SPRING ASSEMBLY ¾
REDUCTION IN COST OF CIVIL STRUCTURE
¾
BETTER LAYOUT
¾
ISOLATION
OF
TG
DECK
AND
COLUMN
WHICH
WILL
AVOID
VIBRATION PROBLEM IN TG COLUMN AT ANY TIME ¾
EFFECT
OF
SETTLEMENT
OF
FOUNDATION
MINIMIZED FOR CATENARY DISTURBANCE
COLUMN
CAN
BE
BHARAT HEAVY ELECTRICALS LIMITED
SPRING LOADED TG DECK : DISADVANTAGES ¾
INCREASE IN ERECTION CYCLE TIME
¾
INCREASE IN OVERHAULING PERIOD
¾
COST OF SPRING ELEMENTS AND ITS INSTALLATION COST
BHARAT HEAVY ELECTRICALS LIMITED
SPRING LOADED TG DECK : BHEL’S RECOMMENDATIONS ¾
USE OF CONVENTIONAL FOUNDATION AS STANDARD PACKAGE FOR NON-EARTH QUAKE PRONE ZONE.
¾
CUSTOMER WHO OPTS FOR SPRING LOADED TG FOUNDATION SHOULD BE INFORMED OF INCREASE IN CYCLE TIME FOR ERECTION AS WELL AS OVERHAULING.
BHARAT HEAVY ELECTRICALS LIMITED
PRE-OUTAGE SURVEY FOR PREDICTIVE MAINTENANCE
BHARAT HEAVY ELECTRICALS LIMITED
AIM OF PRE – OUTAGE SURVEY ¾
TO DETERMINE LEVEL OF DEGRADATION IN THE UNIT
¾
TO IDENTIFY AREAS OF DEFICIENCY
¾
TO PLAN THE SCOPE OF WORK FOR NEXT OVERHAUL
¾
TO PLAN THE SPARES REQUIRED IN THE NEXT O/H
¾
TO PLAN THE MOBILISATION OF MAN, MACHINE, TOOLS AND TACKLES
¾
TO PLAN FOR SPECIAL STUDIES TO BE CARRIED OUT IN THE NEXT SHUTDOWN
BHARAT HEAVY ELECTRICALS LIMITED
TEAM MEMBERS OF PRE – OUTAGE SURVEY (A)
Engineer from Turbine / Generator Group of PSTS (HQ) {LEADER}
(B)
Field
Engineering
Service
Engineer
from
Steam
Turbine
/
Turbogenerator Department from BHEL – Haridwar / Hyderabad / Bhopal (C)
Service Engineer from Regional Service Centre
(D)
Engineer from Regional Spare Business Group
(E)
Vibration Engineer in case, the machine has some history of vibration problem
Note:- After the survey, the team may recommend the visit of additional experts to the site depending upon the problem / investigation needed by the machine on case to case basis.
BHARAT HEAVY ELECTRICALS LIMITED
CHECKS TO BE CONDUCTED DURING PRE-OUTAGE SURVEY ¾
CHECKS DURING THE RUNNING OF POWER STATION
¾
CHECKS DURING THE SHUTTING DOWN OF THE MACHINE
¾
STUDY OF PAST HISTORY OF THE PLANT
¾
PRESENT AVAILABILITY OF SPARES WITH CUSTOMER
BHARAT HEAVY ELECTRICALS LIMITED
BENEFITS OF PRE – OUTAGE SURVEY FOR CUSTOMER ¾
OPTIMAL APPROACH
¾
SHORTER MAINTENANCE PERIOD BY ADVANCE PLANNING FOR SPARE CONSUMPTION
¾
PROVIDES
LEAN
TIME
TO
CUSTOMER
FOR
PROPOSAL
MOVEMENT / SANTIONING OF FUNDS ¾
EDUCATION
TO
CUSTOMER
WRT
NEW
PRODUCT
,
NEW
PHILOSOPHY, NEW FAILURES ETC. ¾
PROVIDES
FLEXIBILITY
TO
POST
PONE
DEPENDING UPON CONDITION OF MACHINE
THE
SHUTDOWN
BHARAT HEAVY ELECTRICALS LIMITED
DECISIONS OF PRE – OUTAGE SURVEY ¾
RUN THE COMPONENT.
o FOR HOW LONG ? o WITH WHAT PRECAUTION ?
¾
REPAIR OF THE COMPONENT
o HELP IN FINALISING SCOPE OF WORK DURING O/H
¾
REPLACEMENT OF THE COMPONENT
o ORDER FOR SPARES WITH OEM TO AVOID DELAYS
BHARAT HEAVY ELECTRICALS LIMITED
UPGRADATIONS FOR NEWER GENERATION OF MACHINES
BHARAT HEAVY ELECTRICALS LIMITED
ADVANCED CLASS STEAM TURBINE BLADES FOR IMPROVED EFFICIENCY TODAY DESIGNER HAS ACCESS TO CALCULATION METHODS, WHICH VERY REALISTICALLY REPRESENT THE FLOW IN A TURBINE. THESE FLOW CALCULATION METHODS ARE USED TO OPTIMISE BLADE DESIGN FROM HP TURBINE THROUGH TO THE LP TURBINE. MOST OPTIMUM TX PROFILE BLADES GIVE HIGHER EFFICIENCY IN TODAY’S STEAM TURBINES. THREE DIMESIONAL BLADES (3DS BLADES) ARE IMPLEMENTED IN HP AND IP TURBINES TO REDUCE SECONDARY FLOW. TWISTED BLADES WITH INTEGRAL SHROUD ARE USED TO REDUCE THE INCIDENCE FLOW LOSSES AND FURTHER INCREASE EFFICIENCY. IN LP TURBINE FINAL STAGES, CURVED STATIONARY BLADES (BANANA BLADES) ARE IMPLEMENTED TO POSITIVELY INFLUENCE THE DEGREE OF REACTION AND TO PREVENT FLOW SEPARATION AT THE HUB. THE OUTER PORTIONS OF THE FINAL STAGE MOVING BLADES HAVE BACKWARD LEANING PROFILES TO ACHIEVE HIGH PROFILE EFFICIENCIES. THE SIMULATION OF UNSTEADY FLOW IN THE TURBOMACHINERY IS A CHALLENGING TASK AND CURRENT RESEARCHES ARE DIRECTED AT CFD MODELING TO SIGNIFICANGLY IMPROVE AERODYNAMIC PERFORMANCE OF THE BLADING.
BHARAT HEAVY ELECTRICALS LIMITED
HIGH PRESSURE ELECTRO-HYDRAULIC GOVERNING SYSTEM FOR STEAM TURBINES HIGH PRESSURE ELCTRO HYDAULIC ACTUATION (EHA) SYSTEM COUPLED WITH DIGITAL CONTROL SYSTEM PRESENTS SIGNIFICANT ADVANTAGES OVER THE CONVENTIONAL LOW PRESSURE SYSTEM. IT IS COMPACT IN SIZE, PTOVIDES QUICKER RESPONSE, BETTER SUPERVISION, AND HIGHER LEVEL OF REDUNDANCY AND IS EASIER TO MAINTAIN. HIGH PRESSURE ACTUATION SYSTEM CAN BE APPLIED FOR MAIN, REHEAT AND BYPASS VALVES FOR STEAM TURBINES OF VARIOUS RATINGS. HYDRAULIC ACTUATORS, POWER SUPPLY UNIT, THE ELECTRICAL CONTROLLER AND THE PROTECTION SYSTEM ARE BRIEFLY DESCRIBED IN THIS PAPER. BHEL HAD ALREADY INTRODUCED HIGH PRESSURE EHA SYSTEM IN HP & LP BYPASS SYSTEM FOR FARIDABAD (NTPC) & DVB COMBINED CYCLE POWER PROJECTS. THIS SYSTEM IS WORKING SATISFACTORILY AT THESE POWER STATIONS. PRESENTLY, BHEL IS IN POSITION TO OFFER HIGH PRESSURE EHA SYSTEM FOR TURBINE BYPASS OPERATION FOR CONVENTIONAL & CCP TURBINES OF ANY RATING. BHEL IS ALSO GEARING ITSELF FOR OFFERING EHA BASED SYSTEM FOR MAIN STEAM TURBINE VALVES.
BHARAT HEAVY ELECTRICALS LIMITED
HIGH PRESSURE ELECTRO-HYDRAULIC GOVERNING SYSTEM FOE STEAM TURBINES THE HIGH-PRESSURE ELECTO-HYDRAULIC GOVERNING SYSTEM ALONGWITH THE DIGITAL CONTROLS OFFER THE FOLLOWING ADVANTAGES: QUICKER RESPONSE PRECISE CONTROLAND EASE OF ADJUSTMENT BETTER SUPERVISION AND HIGHER REDUNDANCY SIMPLIFIED PLANT LAYOUT DUE TO OVERALL CONPACT SIZE EASE OF CHANGING CONTROL VALVE SEQUENCE BETTER INTERCONNECTION WITH OTHER SYSTEMS CONTROL OIL PIPING REDUCED TO LARGE EXTENT GOVERNING AND BYPASS RACKS NOT REQUIRED OPERATION AND MAINTENANCE ARE RELATIVELY EASY
BHARAT HEAVY ELECTRICALS LIMITED
STEAM TURBINES WITH SUPER CRITICAL PARAMETERS Super-critical parameters
221.2 BAR (225.6 ATA) PRESSURE AND 374.15 0C TEMPERATURE IS CALLED CRITICAL POINT OF WATER / STEAM BECAUSE AT THESE PARAMETERS WATER CHANGES TO STEAM PHASE INSTANTANEOUSLY (WITHOUT ANY LATENT HEAT OF EVAPORATION). THE STEAM TURBINES UTILISING MAIN STEAM PRESSURE ABOVE THIS CRITICAL PRESSURE ARE CALLED SUPER-CRITICAL TURBINES. Advantage MODERN SOCIETY’S CONCERN FOR POLLUTANT EMISSIONS FROM THERMAL POWER PLANT AND EVER INCREASING FUEL COSTS ARE TWO DRIVING FORCES FOR DEVELOPMENT OF MORE EFFICIENT POWER PLANTS. EVERY PERENTAGE POINT INCREASE IN THERMAL EFFICIENCY REDUCES POLLUTANT EMISSIONS BY 2.5% AND ALSO SAVES 2.5% ON FUEL COSTS. POWER GENERATION IN INDIA IS DOMINATED BY SUBCRITICAL 500MW SETS OPERATING AT 170 ATA / 537 0C / 537 0C AND 210 MW SETS OPERATING AT 150 ATA / 537 0C / 537 0C. EVERY 50 ATA INCREASE IN MAIN STEAM PRESSURE OR EVERY 22 0 C INCREASE IN MAIN AND REHEAT STEAM TEMPERATURE IMPROVES CYCLE EFFICIENCY BY 1%.
BHARAT HEAVY ELECTRICALS LIMITED
USE OF SS TUBES IN SURFACE CONDENSER FOR ENHANCED RELIABILITY FOR CONDENSERS EMPLOYING SWEET WATER I.E. COOLING WATER OTHER THAN SEA WATER OR SALTY WATER (CONTAINING HIGH CHLORIDES), USE OF WELDED SS TUBES IS RECOMMENDED AS THE BEST MATERIAL FOR ITS SUPERIOR QUALITIES OF BETTER EROSIONCORROSION RESISTANCE, HIGHER RELIABILITY, LONGER LIFE AND LOWER CAPITAL AND MAINTENACE COST IN COMPARISON TO NONFEROUS TUBES LIE ADMIRALTY BRASS, ALUMINIUM BRASS OR CUPRO NICKEL WHICH WERE CHOSEN AS THE TUBE MATERIALS FOR POWER PLANT CONDENSRES IN THE PAST AS PER TRENDS AND TECHNOECONOMICS PREVAILING THEN.
BHARAT HEAVY ELECTRICALS LIMITED
TIPS FOR START UP & SHUT DOWN
BHARAT HEAVY ELECTRICALS LIMITED ¾
FAST COOLING OF TURBINE TO REDUCE THE COOLING DOWN TIME
¾
ALWAYS KEEP MANUAL VACUUM BREAKER OPEN
¾
WHENEVER MACHINE WAS SHUTDOWN FOR LONG PERIOD, DRAIN THE HOTWELL
¾
PRIOR TO START OF OIL PUMPS, RAISE THE OIL TEMPERATURE
