Transcript
WELCOME TO
3 L Program (BEE)
15/05/2008
Piyushkumar Pandya
DGM (Electrical)
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New Technology-VFD at
DTPS
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Introduction
The Energy efficiency and conservation is the prime objective of DTPS
Intensive study done for various Energy system like thermal, Electrical, water
The performance of all Electrical system and loads analysed for optimum resource utilisation
Internal and external audit has signify the vast potential available to be saved in Electrical systems.
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Introduction
Various Energy saving projects implemented like
Implementation of Elan system
Optimisation of lighting system
Installation of solar and LED based lighting system
The motors being the major consumer of Electrical energy
Variable frequency drive has been identified as prime tool
All operational and financial issues like reliability, risk assessment and
cost-benefit analysis carried out for each projects
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Variable Frequency Drive-Tool for Energy saving
Energy waste is identified through internal and external audit
System requirement and equipment design mismatch
Variable frequency drive has been identified as tool
Initially LV VFD commissioned
MV VFD trial and then successful commissioning done
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Detail of Auxiliary Power Consumption
Total Plant Generation 520 MW
Auxiliary Power Consumption 39.50 MW @ 7.6 %
HT Motor Consumption 37.50 MW
LT Motor Consumption 1.50 MW
Lighting & Misc. Consumption 0.50 MW
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Application wise Load detailApplication Total
motor
Motors
in
service
Service
duty
Connect
ed load
(KW)
Running
load
Actual
consumption
Pump 27 13 Continuous 47600 24750 21110
Fan 12 12 Continuous 15700 15700 9848
Compressor 05 02 Continuous 1200 480 426
Conveyor 06 06 Partial 1216 1216 553
Mill 08 04 Continuous 15410 9400 5523
Total 58 37 - 81.126
MW
51.546
MW
37.460 MW
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LV VFD (415V)
HFO Pump-37KW
Seal Air Fan-120KW
Vent Air Fan-90KW
Colony Drinking water Pump-45KW
MV VFD (6.6KV)
Condensate Extraction Pump -650 KW
VFD at DTPS
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HFO Pump-VFD
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DPI
PCV
PCVRETURN TO
HFO TANK
HO28
HO28HO12
HO12 HO12 HO12
HO12HO12
HO11
PP PS PC
PI
PSAL
PT
PI
PI
T
C
V
HEATING STEAM
PI PI PS PI
TI
TI
TC
CONDENSATE
HTR-3
HTR-2
HTR-1
PI
PP
PI
PDIPUMP-3
PUMP-2
PUMP-1
PI
TO
HOTCV
TO
HOPCV
TO
U#1
&
U#2FROM
HFO
TANK
Flow Diagram
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HFO Pump –Process detail During the normal operation of both units, the HFO consumption is
zero
The HFO gets re-circulated through short and long re-circulation line
of both boilers to maintain the HFO temperature
Flow through short & long re-circulation is very less & maximum
quantity of HFO re-circulated through Pressure Control Valve (PCV),
located near the HFO firing pumps to HFO tank.
PCV maintains the HFO discharge header pressure to 21-23 Kg &
remains approx. 50% open during normal operation of both units
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HFO Pump – VFD as Solution
Recirculation is identified as source of energy wastage
Decision taken to install VFD and open the recirculation fully
Risk assessment carried out
Introduction of first VFD for DTPS and hence trial run of VFD planned
Vendor identified for trial run
Operational reliability ensured and energy saving achieved
Permanent installation done
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HFO Pump VFD-Measurement of parameter
Parameter Design Parameter Operating parameter Parameter with VFD
Pressure 23 Kg/cm2 20-23 Kg/cm2 23 Kg/cm2
Valve position Recirculation mode 50% open with recirculation
mode
100% open
Speed 1480 rpm 1480 rpm 1243 rpm
Power 37 KW 18.1 KW 9.74 KW
Cost of VFD : Rs.1.68 Lacs
Energy saving/Annum : Rs.1.70 Lacs
Simple payback : 12 months
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HFO Pump-VFD
The first VFD of DTPS has given Very high saving and confidence.
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Seal Air Fan
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Seal Air Fan
Seal air fan is used for providing sealing to coal Mills, classifier gates and
feeders
There are six Mills and each has two seal air fans
Largest LT auxiliary in DTPS consuming 120KW power
Total power consumption is 480 KW(120KW*4)
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MILL SHELL
SID-1
SID-2SID-1
SID-2
PG
PS
DPS
SID-3
SID-13SID-13
SLD-6 SLD-6
BALL FEED MECH.
COAL FEEDER
MIXING BOX
MIXING BOX
COAL FEEDER
TO CAD
TO CAD
AUTO VISCOUS FILTER
AIR I/L AIR I/L
GIRTH GEAR S.A. FAN
Flow Diagram
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Seal Air Fan-Flow Diagram
20-25% open
3.9 m3/s
1950 mmWc
120 KW
800-900 mmWc
Fan-AFan-B
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Seal Air Fan-Control Philosophy
The seal air fan has the damper control at its suction side
The Header pressure requirement is 800-1000mmwc.
The damper is opened up to 20-25% only.
The rated head is 1650mmwc against operating head of 800-
1000mmwc.
The energy is wasted across the damper.
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Seal Air Fan- Control Philosophy with VFD
Decision taken to install VFD after risk assessment as tripping will lead to
unit tripping & generation loss.
First trial run taken
The seal air fan damper to be open 100%
The speed to be adjusted manually as per the requirement of header
pressure.
One common VFD employed for the two seal air fan of a Mill.
Configuration and logic has been selected so that total capital cost
reduced along with operational flexibility.
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Seal Air fan VFD-Measurement of parameter
Parameter Design Parameter Operating parameter Parameter with VFD
Discharge
Pressure
1650 mmWc 1000 mmWc 800-1000 mmWc
Damper position 25% open Depending upon
requirement
100% open
Speed 1480 rpm 1480 rpm 977 rpm
Power 120KW 110-120 KW 55 Kw
Cost of VFD : Rs.30.5 Lacs
Energy saving/Annum : Rs. 43.00 Lacs
Simple payback : 9 months
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Seal Air fan VFD
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Vent Air Fan-Dry Ash Silo system
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Vent Air Fan – Flow Diagram
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Vent Air Fan – Fan Specification
Capacity- 13300 m3/hr
Head - 510 mmWc
Motor rating-90KW
Actual power consumption-69KW
The rated head of the vent air fan is very high compared to the process
requirement
The damper is throttled heavy (20% open only) leading to significant
pressure loss
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Vent fan VFD-Measurement of parameter
Parameter Design Parameter Operating parameter Parameter with VFD
Discharge
Pressure
510 mmWc 380 mmWc 350-380 mmWc
Damper position 25% open Depending upon
requirement
100% open
Speed 1480 rpm 1480 rpm 1243 rpm
Power 69KW 69KW 48 KW
Cost of VFD : Rs.6.5 Lacs
Energy saving/Annum : Rs. 4.53 Lacs
Simple payback : 17 months
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Colony Drinking water Pump
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Colony Drinking water Pump- Flow diagram
Service water tank
Colony overhead water tank
Pump-A
Pump-B
PG
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Colony Drinking water Pump –Specification
Head - 14 Kg/cm2
Motor rating-45KW
Actual power consumption-40KW
The rated head of the pump is very high compared to the process
requirement (8Kg/cm2)
The valve is throttled (60% open only) leading to significant pressure loss
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Vent fan VFD-Measurement of parameter
Parameter Design Parameter Operating parameter Parameter with VFD
Discharge
Pressure
14 Kg/cm2 14 Kg/cm2 8 Kg/cm2
Valve position - 60% open 100% open
Speed 2955 rpm 2955 rpm 2233 rpm
Power 45 KW 40 KW 25 KW
Cost of VFD : Rs.1.6 Lacs
Energy saving/Annum : Rs. 3.3 Lacs
Simple payback : 5 months
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Colony Drinking water Pump VFD
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MV VFD-Advantage & Barriers
Advantages:
High Energy saving potential
To achieve objective of aux. Power
Better Process control
Proved Technology
Reduce O&M expense
Barriers :
Penetration is less in power plants
Cost is high
Reliability
Competency of Drive manufacturer
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Condensate Extraction Pump
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Selection of CEP for VFD application
CEP has solo operation, and comparatively easy to control.
ID/PA/FD fans are continuously runs on sharing basis.
Hence one fan trial with VFD was complicated.
BFP rating is 9 MW hence availability of this rating VFD is difficult.
Hence CEP was selected for trial operation of VFD
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CEP- Flow Diagram
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CEP- Energy saving with MV VFD
Operating Issues:
Existing system to be retrofitted with Drive.
Control valve feedback signal to VFD can be given
Only one VFD module is considered for each unit.
Operation C/O practice to be reviewed to get max. energy saving
Protection system to be reviewed.
Control logic and setting to be modified.
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Operating and protection interlocks
9950+51
86
50+51 INSTANTENEOUS OVER CURRENT A.C
TIME OVER CURRENT RELAY
86 LOCKING –OUT RELAY
94 TRIPPING OR TRIP FREE RELAY
74 ALARM RELAY
99 MOTOR PROTECTION RELAY
Modified SLD for VSD installation
1 .In put Isolator
2. Bypass Isolator
3. Out put isolator
VSD-CEP-A-2
MOTOR
3~
12 3
94 74
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Protection scheme
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VFD specification
Rating :880KW with bypass arrangement
Voltage:6.6KV,50Hz,3 phase
Overload cpacity:120%
Insulation class – H
36 pulse control with constant V/f
Remote/Local and Analogue/Computer mode selection
Make : Beijing & leader, Beijing
Supplier : M/s.Yantra Automation Pvt. Ltd, Pune.
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Measurement of parameter
Parameter Design Parameter Operating parameter Parameter with VFD
Capacity 770 M3/hr 640 tons/hr 640 tons/hr
Head 20.5Kg/cm2 21.3 Kg/hr 14.5-15 Kg/cm2
Temperature 45.8 0C 45 0C 45 0C
Speed 1480 rpm 1480 rpm 1300 rpm
Power 650 KW 590 KW 440 KW
Control system Dearator level control
through Valve control
Dearator level control
through Valve control
Dearator level control through Speed
control
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Cost-Benefit Analysis
Power consumed without VFD : 590KW
Power consumed with VFD : 440KW
Net power saving :150KW
Annual energy saving :Rs.44.1 Lacs
Cost of VFD :Rs.75 lacs
Payback period :17 months
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VFD Protection
Under voltage: 0.65 Un
Overload :120% for 60 seconds
Short circuit current :150% instantaneously
Power cell Temperature :85o C
Transformer temperature alarm : 120 oC
Transformer temperature :130o C
Cell Bypass : Max. two cell
Local emergency push button :Enable
Cell cabinet temperature alarm : 40o C
Cell Cabinet temperature trip :45oC
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HMI –MV VFD
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Installation of CEP VFD
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Installation of VFD
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MV Drive-Basic Configuration
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MV Drive-Principal
Speed of an electric motor is determined by
1.Supply frequency
2.Number of pole pairs
Speed = Frequency x 60 Number of pole pairs
Speed of a 2 pole motor on 50Hz is 3000RPM (3600RPM on 60Hz)
We must change the frequency to change the speed
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The Ideal Variable Speed Drive
Driven
Load
Supply
Network
No harmonic
voltage or
current
distortion
Near unity
power factor
No harmonic
heating
No insulation
stress
No additional
bearing current
No
rotational
torque
oscillations
Fault tolerant
enabling
operation
with one or more
failures
Easy repair
High Efficiency
Converter Motor
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The Basic Variable Speed Drive
INPUT
TRANSFORMER
RECTIFIER INVERTER
MOTOR
DC LINK
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The Power Cell schematic
Dedicated winding
on power transformer
Power Output of Cell
Logic
Control
Power
Fiber Optic Signals to
and from master controlLogic Control Circuits
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Power cell
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Power cell arrangement
Thank you
May 12 2008
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