COntrol systems thesis proposal

7/31/2019 COntrol systems thesis proposal

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MASTER THESIS PROPOSAL

FacultyofTechnologyandScienceDepartmentofPhysicsandElectricalEngineering

"Analysis and reporting of the control tests conducted in connection with

commissioning for control system upgrade at Ringhals 2."

Submitted by

Jibran Baladi(19850517-T218)

Naeem Ullah Khan(19870306-T310)

Submitted to

Jorge Solis, PhdExaminer

DegreeProjectof30creditpointsMastersPrograminElectricalEngineering

Date:August21th2012

Supervisor: ThomasJohansson.VattenfallAB

Supervisor: JonasOlandersson.VattenfallAB

Supervisor: Examiner: JorgeSolis.KarlstadUniversity

Karlstad University, 651 88 KarlstadPhone: 054-7001000, Fax: 054-7001460

[email protected] www.kau.se
mailto:[email protected]://www.kau.se/http://www.kau.se/mailto:[email protected]


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Master Thesis Proposal Naeem Ullah Khan

Jibran Baladi

IntroductionVattenfall is a leading European energy company, whose main products are electricity and

heat. Today, Vattenfall supplies energy to several million customers in Scandinavia and

northern Europe. Vattenfall operates its four nuclear reactors at Ringhals and other three atForsmark.

Ringhals nuclear power plant has one boiling water reactor (R1) and three pressurized water

reactors (R2, R3 and R4). The three pressurized water reactors (R2, R3, R4) were

manufactured by Westinghouse Electric. Ringhals 2 has an installed electrical capacity of

865MW and went commercial in May 1975 [1]. Ringhals 2 nuclear power plant is a

pressurized water reactor (PWR) supplied by Westinghouse. A pressurized water reactor leads

the heated coolant to a heat exchanger (steam generator) where steam is produced for driving

the steam turbine and a generator which in turn generates electrical energy. During the period

May 2009 February 2010, Westinghouse Electric was responsible for major maintenance

efforts for an extensive modernization of control equipment, which included a new controlroom equipped with digital technology was installed.

BackgroundDue to aging factor of system instrumentation in different nuclear power plants, system

reliability and outcome is decreasing with increasing cost of maintenance, testing, component

replacement and spare parts [2]. In this regard the nuclear industry modernizes existing analog

I&C with new digital technology to reduce maintenance costs and efforts and to get more

efficient, reliable and intelligent control systems.

When Westinghouse Electric started the outage commissioning of Ringhals 2 Nuclear powerplant, major overhauling and maintenance efforts were put into for bringing the new digital

control system (DCS) and new instrumentation through site acceptance test (SAT) towards

power generation. SAT is test after equipment assembling and has to demonstrate that system

did not suffer any defects and it is assembled correctly during erection on site, and that all its

functions are available [3].

Fig. 1 Test strategy for digital control system.

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Jibran Baladi

I&C (Instrumentation and control architecture) contains various elements like sensors,

equipment modules, transmitters etc [4]. It can read process variable, set point and valve

position and can sense all kind of other physical parameters. The modernization of the

complete I&C were carried out by Westinghouse. The calibration, testing, conditioning and

aligning of all pressure, flow and level transmitters was done in this modernization. Finally,

after the complete overhauling of Ringhals 2 nuclear power plant Westinghouse documentedall the test procedures in the form of reports for every control loop.

Local optimal control (LOC) approach is suitable for controlling multivariable and SISO

(Single Input and Single Output) systems. This digital PID controller tuning technique is

based on LOC and this can be used to tune digital PID controller parameters using model

parameters and single controller parameter [5]. LOC technique is compared with other

algorithm techniques for tuning digital PID controllers and it shows great effectiveness over

other genetic algorithm techniques in robust performance point of view.

The LOC designed model structure of the system gives very good results even if the real

system is of higher order. The digital PID controller block diagrams shown in fig 2, the

following relationship are obtained [6] where:

{{{{ . {

Fig. 2 Block diagram for digital PID controller.

{6 0{I{I 6 -

{ . # -0{ .

#{

From (1) the following equation can be obtained

{ { . { . {6 - -0{ . {6 -0{ . - 0{ . {2nd order system model { represented in (3) as:

{I {I{I I

I$ - #I - $ {

The following equation is obtained from (3) and represents the system model

{ #{ . . ${ . - { . {

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Jibran Baladi

The modified LOC for the system model given in (4) is represented in the block diagram

shown in fig. 3 as:

Fig. 3 LOC designed for 2nd

order model of the plant.

The following input discrete time integer equation can be evaluated from fig.3 as:

{ @ { - #{ - {$ . #{ . . ${ . D {

The digital PID controller parameters in term of LOC parameters are obtained from above

equations as:

H {

H H

{

Problem Definition

In Ringhals 2, Westinghouse electric conducted control tests on several control loops;

these tests were conducted on the basis of stability and performance of the PID controller

using step response test. If the criteria was not fulfilled of stability and performance then

PID controller parameters were retuned until the desired results. So now the concern issue

with Ringhals 2 is; are there any control loop problems and control risk currently on

Ringhals 2 and how is it possible to eliminate the biggest control problem in Ringhals 2?

Therefore, the problem definition of this thesis is to develop a comprehensive debriefing of

all control tests conducted by Westinghouse Electric after modernization and testing of

control system upgrade for DCS (Distributed Control System) type. Literature study of all

conducted tests with the evaluation of which one needs deeper analysis according to the

requirements as per directed by the company. Perform and document in-depth analysis of one

or more control loops with strong and observed suggestions. The final report will provide the

summarize results and assessments of previously conducted tests with the reasons why

chosen test is analyzed in detail [7]. This will be achieved by analyzing the measured data,

the design of existing facility, construction and implementation of the selected control loop(s).

Simulation (possibly in MATLAB/Simulink or any other software recommended by Ringhals2

Nuclear Power Plant) for the suggested model, which will show important problem

images/blocks like sensors, actuators, control, thermal hydraulics etc.

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Master Thesis Proposal Naeem Ullah KhanJibran Baladi

Methodology Firstly; literature review, study and analysis of all the numerous control loops reports

will be carried out at Ringhals nuclear power plant, which was provided by

Westinghouse Electric to Ringhals after upgrading and testing all the control systems.

Simultaneously, these control loops results will be carried out for analysis andinspection to check whether the performance and stability criteria of the control

loops are fulfilled.

With the observed results of all the control loops, precise selections for a number of

control loop(s) are to be made for modeling, tuning and testing. Model estimation and

controller design will be carried out using suitable method(s) described below or any

other method which will help in improving the performance of the control loops.

Several strategies are available that can be used to improve the model and estimate theparameters like Recursive least square method, Kalman filter, Augmented extended

Kalman filter, etc. Depending on the control loop model either one of these or any other

strategy can be used in the future which will help in improving the performance of the

model.

Similarly controller design can be based on different principles like Minimum variancedesign, Linear quadratic control design, Model predictive control design [8] or any other

approach can be adopted which will suit our requirements in the future.

Modeling, testing and tuning will be carried out using Matlab/Simulink or any other

software recommended by Ringhals AB.

Final summary report with recommendations and suggestions of the selected control loops

will be provided to Ringhals AB.

Expected ResultsAfter in-depth study of control loops reports and making precise selection of control loop(s),

will lead towards controller design and modeling. As discussed in the methodology,

controller design and modeling will be carried out by using any of the above method or any

other suitable strategy depending on the loop. Mainly, the objective is to provide Ringhals 2 a

controller design that will practically save energy, minimize maintenance cost, minimize

valve travel, reduce interference between loops, manage transient, etc. This performanceimprovement can cause the process variable to be near to the set-point with less overshoot

and fewer oscillations in the step response test as compared to the reports of Westinghouse

Electric. Subsequent to analyzed modifications, system is to be modeled with suggested new

parameter values; for the future operation of Ringhals 2 nuclear power plant.

Expected conclusionA comprehensive debriefing to be done for the previously conducted reports provided by

Westinghouse at Ringhals 2 nuclear power plant for each control loop. Moreover, after deeply

analyzing the Westinghouse reports, a recommendation to be forwarded to Ringhals 2 nuclear

power plant on the basis of obtained results and conclusions with strong reasoning. Numerousnumber of necessary control loop(s) to be documented and tested with proper and technical

suggestions by observing and analyzing the measured data and models.

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Jibran Baladi

Project ScheduleThesis work has started from 14th of August 2012 and will take 20 weeks/5 months to

complete. Weekly schedule will be purposed soon after the number of reports selected for

further studies and on the number on control loop to be tested.

References[1]. http://www.vattenfall.se/sv/ringhals-nuclear-power-plant.htm

[2]. Ornellas, R.P.; Gross, R.S.; , "Strategies for instrumentation and control

upgrades," Nuclear Science Symposium and Medical Imaging Conference,

1994., 1994 IEEE Conference Record, vol.3, no., pp.1047-1050 vol.3, 30 Oct-5

Nov 1994

URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=474662&isnumber=10004

[3]. Petruzela, I.; , "Testing of a Reactor Control System in Closed-Loop," Industrial

Electronics, 2007. ISIE 2007. IEEE International Symposium on , vol., no.,

pp.314-317, 4-7 June2007

URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4374618&is

number=4374555

[4]. http://www.iaea.org/NuclearPower/IandC/

[5]. Ashry, M.M; Kamalova, Z.Z; Brreikin, T.V; , Tuning of Digital PID ControllerParameters using Local Optimal Control, Control and Automation, 2006 16thMediterranean Conference on, vol., no., 587-592, 25-27 June2008 URL:http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4602200

[6]. K. Ogata, Discrete-time control systems, 2nd ed., Prentice-Hall, 1995.pp. 98-

121.

[7]. http://www.vattenfall.se/sv/lediga-jobb.htm

[8]. Bjorn Sohlberg, Applied Model Based Control, 2008 Edition.

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http://www.vattenfall.se/sv/ringhals-nuclear-power-plant.htmhttp://www.vattenfall.se/sv/ringhals-nuclear-power-plant.htmhttp://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=474662&isnumber=10004http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=474662&isnumber=10004http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4374618&isnumber=4374555http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4374618&isnumber=4374555http://www.iaea.org/NuclearPower/IandC/http://www.iaea.org/NuclearPower/IandC/http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4602200http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4602200http://www.vattenfall.se/sv/lediga-jobb.htmhttp://www.vattenfall.se/sv/lediga-jobb.htmhttp://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4602200http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4602200http://www.iaea.org/NuclearPower/IandC/http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4374618&isnumber=4374555http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=4374618&isnumber=4374555http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=474662&isnumber=10004http://ieeexplore.ieee.org.bibproxy.kau.se:2048/stamp/stamp.jsp?tp=&arnumber=474662&isnumber=10004http://www.vattenfall.se/sv/ringhals-nuclear-power-plant.htm

COntrol systems thesis proposal

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