vfd - dtps

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


Discharge

Pressure

1650 mmWc 1000 mmWc 800-1000 mmWc

Damper position 25% open Depending upon

requirement

100% open


Power 120KW 110-120 KW 55 Kw


Energy saving/Annum : Rs. 43.00 Lacs


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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


Discharge

Pressure

510 mmWc 380 mmWc 350-380 mmWc

Damper position 25% open Depending upon

requirement

100% open


Power 69KW 69KW 48 KW




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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


Discharge

Pressure

14 Kg/cm2 14 Kg/cm2 8 Kg/cm2

Valve position - 60% open 100% open


Power 45 KW 40 KW 25 KW




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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


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


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

vfd - dtps

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