flexibilisation of bhel supplied sets: the way forward · flexibilisation of bhel supplied sets:...

Flexibilisation of BHEL supplied sets: The Way Forward

Yatheesh M. Babu

General Manager

Power Sector- Technical Services, Noida

04th February, 2020

POWER SECTOR – TECHNICAL SERVICES

2


Presentation Agenda

FLEXIBILISATION : THE CONCEPT

What? Why? How?

FLEXIBILISATION & BHEL

Case Study

MITIGATING THE EFFECTS

The Way Forward


3

WHAT ? WHY ? HOW ?

FLEXIBILISATION



4

The Rise of Renewable Energy

THE RISE OF RENEWABLE ENERGY GENERATION

▰ 105 GW renewable generation addition by 2022. Thereby taking the figure to 175 GW

▰ The share will increase from current 20% share to 37% share in 2022 and further 44% share is target by 2027.

▰ Solar & wind will have a contribution of 21% & 12.5% respectively of the total generation capacity in 2022

S. No. Sector

Installed Capacity (in GW)

2017-18 2021-22

1. Coal + Lignite 197 217

2. Hydro 45 51

3. Gas 25 26

4. Nuclear 6.7 10

5. Solar 22

6. Wind 34

7. Biomass 9

8. Small Hydro 4

Total 344 479

Source: CEA



5

LIMITATIONS WITH RENEWABLE ENERGY SOURCE

▰ Intermittent and variable

▰ Season and Weather dependent

▰ Location and time of day dependent

▰ Does not match the load demand curve

▰ Wind generation is unpredictable

▰ Solar generation is predictable but non controllable

Flexiblisation: The Need

FOR BALANCING THE GRID (LOAD GENERATION BALANCE)

▰ Off-peak and peak demand variation

▰ Sudden increase of load in the grid

▰ Loss of grid connected load

▰ Loss of generation in the system

▰ Addition or reduction of RE generation

Maximum Solar & Wind Generation(Predicted on 25.06.2021)



6

Flexibilisation: The Expectations

EXPECTATIONS FROM THE THERMAL PLANTS

▰ Higher ramping rates during loading and unloading

▰ Faster Startup

▰ Lower stable minimum load

THE PRACTICAL OPERATIONAL REGIME IN FLEXIBLE OPERATION WILL BE AS:

▰ Frequent & increased load cycling

▰ Fast load ramp up and ramp down

▰ Low load operation

▰ Two shift operation

▰ Frequent and increased number of unit startup & shutdown cycles

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40%

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80%2% / min 3% / min



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Effect of Load Cycling

CREEP

Slow and continuous deformation of materials due to high temperature exposure even at constant load

THERMAL FATIGUE

Failure of metal when subjected to repeated or fluctuating stresses due to thermal cycling of components

COMPONENTS

▪ HP/IP rotors

▪ Blades

▪ Casings

▪ Valves

▪ Header

▪ Y-Piece

▪ T-piece

▪ MS/HRH Pipelines

▪ Pressure parts

DEPENDING ON THE OPERATIONAL CONDITIONS, TURBINE & BOILER COMPONENTS ARE EXPOSED TO VARIOUS DAMAGE MECHANISMS:



8

THE JOURNEY

FLEXIBILISATION & BHEL


9

Flexibilisation: Journey so far


BHEL’s FORAY INTO FLEXIBLISATION INITIATIVE

▰ Part of IGEF / EEC

▰ Working in close coordination with agencies, such as CEA, for implementing flexiblisation in Indian power sector

▰ Closely working with our customer to understand how they perceive flexiblisation & hence their expectations

▰ Building flexiblisiation portfolio to meet customer’s & market’s requirements

THE CASE STUDY

▰ Capability of BHEL sets for flexible operation (some operational limitations & added life consumption)

▰ Dedicated solutions for enhancing plant’s reliability & availability

▰ Confidence to statuary authorities

▰ Avoid furore that flexibility will jeopardize the existing plants

▰ Identify required solutions to achieve current/ future level of flexibility requirement


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Flexibilisation: Pilot Study


LOAD RAMPING : STUDY

▰ Load ramping tests have been carried out at:

• 1% ramp up & down



▰ Load range of 55% to 100% TMCR

▰ Unit operation in CMC with slight manual intervention

▰ Load change has been done both in coupled blocks of 50-125 MW & in single block of 225 MW.

▰ Results have been quite encouraging and as per our expectations

LOAD RAMPING : CHALLANGES

▰ Unit stability – furnace stability – flame stability –excess air flow

▰ Unit response

▰ SHO & RHO temperature deviations

▰ Combination & number of mills in service

▰ BFP – single stream/ double stream operation

▰ AFG path – single stream/ double stream operation

▰ FG temperature deviations

▰ Emission control equipment (currently ESP only)

▰ State of the plant – O & M practices

▰ Fuel characteristics


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Pilot Study: Load Variation


CASE 1

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500

550

Load M

W

3% Ramp Test 1% Ramp Test

Load Set PointActual Load

CASE 2

150

200

250

300

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400

450

500

550

3% Ramp test


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Pilot Study: SHO Temperature Variation


420

460

500

540

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620

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Tem

p D

egC

Load M

W

Time

Actual Load SHO Temp SHO Temp SP

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460

500

540

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620

660

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SH ATTEMP FW FLOW (LINE-B) ACTUAL LOAD

MS SH O/L (RHS) TEMP1

CASE 1 CASE 2


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Pilot Study: RHO Temperature Variation


433

478

523

568

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658

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Tem

p D

egC

Load M

W

Time

Actual Load RHO Temp RHO Temp SP

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478

523

568

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658

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ACTUAL LOAD HRH STEAM TEMP RH O/L (RHS)

CASE 1 CASE 2


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Pilot Study: Variation in Drum Parameters


-250-220-190-160-130-100-70-40-10205080110140170200230

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Dru

m L

evel

Load M

W

Time

Actual Load Drum Level

-250-220-190-160-130-100-70-40-10205080110140170200230

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ACTUAL LOAD DRUM STEAM PRESS DRUM LEVEL ACTUAL

CASE 1 CASE 2


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Pilot Study: The Fireball


500 MW200 MW



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MITIGATING THE EFFECTS

FLEXIBILISATION


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Cyclic Loading: Mitigating the Effects


▰ Customized operating guidelines

▰ Thermo-mechanical assessment

▰ Condition monitoring systems/ Sensors

▰ Controls & Automation Package

▰ Model based / Adaptive Control Systems

▰ Fuel Firing System Optimization

▰ Plant Optimizer

▰ Advisory Services for Flexible Operation

▰ Improved design of Boiler and Turbine to allow faster ramping and increased number of cycles


18

Customized Operating Guidelines


CUSTOMIZED OPERATING GUIDELINES

▰ Low load operation

▰ Load ramping at required ramp rates








19

Thermo-mechanical Assessment


THERMO-MECHANICAL ASSESSMENT

▰ Detailed thermo-mechanical assessment of unit

➢ Current state of the equipment

➢ Response and capability for flexible operation with a set of proposed fuel








20

Condition Monitoring Systems


CONDITION MONITORING SYSTEMS

▰ Dedicated Packages for stress monitoring in:

▰ Boiler

▰ Turbine

▰ Generator








21

Controls & Automation


CONTROLS & AUTOMATION PACKAGE

▰ Fine tuning of Existing Controls

▰ Customised Control Packages for various sub-controls

▰ Complete Control Package

▰ Upgradation of older control systems either through complete R&M or additional packages








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Model based / Adaptive Predictive Control (MPC/APC)


Existing PID Controller Philosophy

MPC Philosophy








23

Model based / Adaptive Predictive Control (MPC/APC)


Conventional PID Control

MPC Software runs in

Workstation

Inputs to PID Controller

Inputs to MPC Software

PID Selection from HMI Station

Relevant DPU in MAX DCS

PID Output to DESH spray control valve

During training of MPC

Conventional PID Control

MPC Software runs in Workstation

Inputs to PID Controller

Inputs to MPC Software

Selection from HMI Station

Relevant DPU in MAX DCS

MPC Output to DESH spray control valve

During running of MPC

ADVANCED TYPE CONTROLLER PRIMARILY FOR STEAM TEMPERATURE CONTROL FOR BOTH SH & RH:

▰ Consists of predictor & controller

▰ Predictor creates models based on past operating data and then predicts the parameters in future course

▰ Based on the prediction, the controller regulates the spray control valves.

▰ Continuous communication between MPC & DCS.

▰ Automatic updating of models.

.


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Advisory Services


ADVISORY SERVICES FOR FLEXIBLE OPERATION

▰ Replacement of fatigued/ worn-out components

▰ Shorter inspection period

▰ Customized O&M guidelines

▰ Customized maintenance schedules

.








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THANK YOU

YATHEESH M. BABUGeneral Manager

Power Sector-Technical [email protected]


flexibilisation of bhel supplied sets: the way forward · flexibilisation of bhel supplied sets:...

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