Engineering Magazine

CONTENTS

Engineering & Technology Development Manager :

* Eng. Magdy Mahmoud

Email. [email protected]

Tel. 26185626

Editor: :

* Dr. Mohamed El-Banhawy


Tel. 26185643

Editorial Board:

* Eng. Wael Yousef


Tel. 26185812

Magazine Design:

* Khaled Negm


Tel. 26186549

Magazine team:

PGESCo is the Tekla Structures - Winner of Middle East 2013...3

Zero Day Vulnerabilities .....5

Modular Switched Mode Power Supplies (Rectifiers), Compared to

convention Transformer/rectifiers.8

Forward Dynamics Model For Designing Large-Size Wind Turbine

Blades ....11

HV Shunt Reactor Protection....16

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Editors Note..

Since this Magazine has been on PGESCo Intranet on May 2012 until this issue, wed have published 8 issues including about 40 technical articles written by PGESCo engineering staff, representing their excellence in technology development serving the Egyptian and International power industry. After each issue we usually feel worried on what we will have for the next issue, but with gratitude to PGESCo staff; they never fail us, with a number of diversified articles that is against our initial expectations.

In this issue, you will read about how PGESCo Civil Engineering was able to win Tekla Middle East BIM Award, which is an annual competition among all companies using Tekla Structures software in the Middle East region. The second article in this issue- and for the first time- is an article by Ahmed Nabil of IT department on the Zero Day Vulnerabilities discussing one of the very important security subjects on the IT world. The 3rd article by Mohamed El-Nady (Electrical) discusses Modular Switched Mode Power Supplies (Rectifiers), as Compared to convention Transformer/rectifiers that is used in all power plants projects.

In the fourth article, Ahmed Bayoumi (Plant Design) presents part of his research on the design of Large size Wind Turbine blades, it is somewhat difficult issue, especially for me as Electrical engineer, but those of you who are interested in this field will find it fascinating. The last article is written by Alaa Abdu (Electrical) presenting Practical Example on EHV (400 KV) Shunt Reactors Protection System, applied in IRAQ Baiji project, engineered by PGESCo project team.

I wish you enjoy this issue and well be awaiting your comments and your excellent contribution to appear in our coming issues. With my best regards;

PGESCo Engineering Magazine ISSUE VI I I Febr u ary , 2 01 4

On The Cover

400 KV Shunt Reactor of Iraq-Baiji Power Plant Project

PGESCo is the Tekla Structures - Winner of Middle East 2013

Tekla Structures Software Tekla Structures is a 3D building information model-ing (BIM) software used in the building and construction industries for steel and concrete detailing, precast and cast in-situ. The software enables users to create and manage 3D structural models and guides them through the process from the design concept to the construction progress. Also for an integrated workflow, Tekla software can easily link with many other software such as; STAAD Pro, SAP 2000, ArchiCAD and SmartPlant 3D. Having 30 localized environments and 14 user interface

languages, Tekla Structures is considered one of the pow-

erful software solutions that have different configurations

to cover different needs.

Baiji Power Plant 6x160 MW. The Baiji Power Plant project is located approximately 16.5 km to the North of Baiji City Centre. The site area is ap-proximately 660,000 m2. The project consists of 3 mod-ules; each Module consists of 2x160 MW Gas Combustion units. The power plant was designed to include: 1. Power block consisting of six (6) gas turbines founda-

tions & buildings, control & switchgear building, and transformers & exhaust stacks foundations

2. Auxiliaries consisting of water treatment area, fuel treatment and handling area, fuel tank farm, firefighting pump house, foam building, auxiliary boilers area, black start & emergency diesel generator building, compressed air building, and HV GIS & control build-ings

3. Ancillaries consisting of administration building, work-

shop & store buildings, canteen, firefighting building,

security gatehouse, mosque, bachelors houses and

guard towers

Tekla program, as a PGESCo standard tool for modeling its

mega power plant projects, was used in modeling the rein

forced concrete and structural steel buildings and struc-

tures, in addition to the storm drainage system, roads and

gantry towers in the same model. In order to accommodate

PGESCo drawings standard environment, the civil design

team had to develop specific drawing settings, automatic

macros, attributes, and templates. Then,

with CIS/2 exchange method all concrete and steel models

were imported in SmartPlant 3D to coordinate with archi-

tectural, plant design, mechanical and electrical models. By

applying this process, the team succeeded in reducing the

time and increasing the accuracy which by return improved

the overall performance of production.

Tekla Middle East BIM Awards 2013 Tekla Middle East BIM Awards is an annual competition among all companies using Tekla Structures in the Middle East region. The winners are determined by public voting and a jury consisting of leading BIM experts inside and outside Tekla. The winners of this competition are entitled to receiving; Trophy, Certificate, Promotion on the web and press release during Tekla Middle East User Day.

PGESCo is the 2013 Middle East Winner 1. In this year competition, only two (2) projects out of

(11) won in the Middle East region. PGESCo has won the Best Concrete Award 2013 for the BAIJI SIM-PLE CYCLE POWER PLANT project. The list of

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Tekla 3D-Model Snapshot Showing Overall View of the Civil/Structural Commodities

Tekla 3D-Model Snapshot Showing Full Details of Reinforcement

PGESCo Civil-Designers Team Congratulations for winning the TEKLA Best Concrete Award-2013 for the Middle-East Region Congratulations for topping 10s and 10s of prestigious mega-projects on the planet earth and being among the top seven in the concrete works across the globe Congratulations for having the TEKLA concrete program for the first time in 2012 and achieve this exceptional per-formance in the year 2013 Congratulations for receiving recognition from interna-tional unbiased experts who appreciate the value of you and your work

Biography:

Ali Bassyouny is PGESCo Chief-Civil hav-ing 30 years of work experience18 years out of them at PGESCo. He obtained his; B.Sc. and M.Sc. in civil/structural engineer-ing from Ain Shams University (EGYPT) in

1983 & 1989; one year Diploma in Hydropower Develop-ment and Management from NTH (Norway) and CSU (USA) in 1990 & 1994; and one year Diploma in ATQM from BEC/ilm (EGYPT) in 2013. He also received several training courses in engineering, power plants and manage-ment in Egypt, USA and Sweden.

competitors in 2013 included: Baiji Simple Cycle Power Plant - by PGESCo Baiji, Iraq

2. King Abdulla Sports City - by Sixco - KSA 3. Central Market Re-Development Towers Project - by

William Hare Abu Dhabi, UAE 4. Salalah Airport, Passenger Terminal Building - by

Eversendai - Salalah, Oman 5. Sadara Hyco Reforming Furnace - by Hidada Co. Lim-

ited Al Jubail, KSA 6. Air Traffic Control Tower - by Hadeed Steel Industries

FZC Salalah, Oman 7. Masdar Headquarters - by Eversendai - Abu Dhabi,

UAE 8. Conrad Hotel, 51 story tower - by Al Nasr Engineering

- Dubai, UAE 9. Dubai Creek Crossing - by Emirates Precast Construc-

tion - Dubai, UAE 10. Safco V Urea Stand Alone Project - by Arabian In-

ternational Company - Al Jubail, KSA 11. Jack Up Crane Barge with Accommodation - by Gulf

Piping Company.

Tekla Global BIM Awards 2013 Since PGESCo project is the winner for the Middle East region, it automatically entered the Tekla Global BIM Awards 2103 competition with another (45) projects cov-ering (18) regions and countries across the globe from Europe in the North to Australia in the South and India in the East to North America in the West to compete for the TEKLA Global BIM Awards-2013 under five (5) categories, as follows:

1. TOTAL BIM Projects (6) 2. ENGINEERING Projects (5) 3. CAST IN PLACE Projects (7) 4. STEEL Projects (21) 5. PRECAST Projects (7)

PGESCo project is competing with six (6) projects under category (3) CAST IN PLACE Projects as follows: 1. Baiji Simple Cycle Power Plant - by PGESCo Baiji,

Iraq 2. BB&T Ballpark, Knights Stadium - by Wayne Broth-

ers Inc. & Harris Steel - Charlotte, USA 3. Espoo Metro - by A-Insinrit Suunnittelu Oy - Hel-

sinki and Espoo, Finland 4. Knislinge Power Plant - by WSP Bridge & Civil Engi-

neering - Skne, Sweden 5. London Bridge Columns - by Midland Steel - London,

UK 6. Op Santfort Apartment Complex - by Bouwmij

Janssen - Grubbenvorst, The Netherlands 7. Pantin-Terralia, residential building - by BET, CBC &

Vinci - Pantin, France

Zero Day Vulnerabilities

What is Zero-Day Attack? Normally Hackers and bad people tend to exploit a vulnera-bility or a hole in your security system to gain unauthorized access to a system and hack it for different purposes. As se-curity professionals we tend all the time to ensure that our systems are fully patched, our devices have the latest firm-ware, Firewalls are in place with the most efficient rules run-ning on them and we are using the latest updated software versions. However just imagine in your house that you have a vulnera-bility or a hole in your system. For example, a broken base-ment window that neither you nor your security guard are aware of. The thief or intruder gained access to this window and was able to access the house. You did not become aware of this vulnerability or broken window until the intruder al-ready exploited it and used it to attack your home. This is Zero-Day attacks and Vulnerabilities. Zero-Day attack is an attack that makes use of an unknown vulnerability in your computer application, software or hard-ware. You and the software vendor are not aware of it. Its

called Zero-Day attack because the attack occurs on Fig 1. Zero-Day attack Life Cycle, Source

http://securityaffairs.co/wordpress/ day Zero of being aware of this vulnerability and attack. The Vendor or the Software developer who created this program or software had zero days to discover, address and fix or patch this security or vulnerability problem.

According to Wikipedia official definition, Zero-day at-tacks occur during the vulnerability window that exists in the time between when the vulnerability is first exploited and when software developers start to develop and publish a counter to that threat.

Zero-Day Attack Lifecycle

The lifecycle of a zero-day attack and Vulnerability ex-ploitation is divided into the following seven phases: 1. The vulnerability is being discovered by the bad

guy/Hacker. 2. The hacker exploits this vulnerability and generates his

code or attack to hack this vulnerable system or sys-tems.

3. The Vulnerability is discovered by the Vendor either by his own team (while testing the software) or from the feedback and problems reported by the customers.

4. The Vulnerability is released for the public and every-one having this software or application should be aware of it.

5. The first action taken by the Security vendor is to re-lease an Antivirus new signature or IDS/IPS (Intrusion Detection/Prevention System) signature to at least stop the at-tack from hitting your application or sys-tem. 6. The Next step done by the Security vendor will be to release a patch or fix to fully close and solve this problem (Root Cause Fix). 7. The Last phase will be the client re-action and time when he received this patch/fix and when its deployed to his applications/systems (Incident Re-sponse). Many Customers will first test this new patch or fix first before deploy-

ing it (Recommended way).

Zero-Day Statistics in 2013 Based on different statistics from different companies, it looks like 2013 was the year of Zero-Day exploits and at-tacks. FireEye has identified seven (7) Zero-Day exploits during the First half of 2013 while Symantec identified

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Introduction Zero day vulnerabilities can be extremely serious security risks. Although there has been a lot of discussion, blogs and warnings about the Zero-Day vulnerabilities, it is still not common and clear for most of security teams. In this article I try to explain what is exactly this zero-day exploits and why is it so dangerous, risky and most importantly I discuss how to protect your assets, systems and data from this kind of attack. I will go through the main Zero-day attacks and Vulnerabilities that occurred in 2013 and the main products and software that was highly affected.

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How to Protect from Such Attack? Protection against Zero-Day attacks is as if you are search-ing for a needle in haystack. There is no way to fully pro-tect against such threats since they are unknown and you are only aware of them when they hit you. We just cannot patch our current software and update our Antivirus to pre-vent them since there are already no patches for them. So how can we mitigate or protect our systems? 1. Common Vulnerable Software (Java): Based on the

statistics from 2013 and the previous five years, we can see that some software has been hit by Zero-Day attacks more than others. This Category includes Java, Flash Player and Internet Explorer. I am not sure if there will be future attacks on these products but based on their back history and number of attacks especially for the Java I would highly recommend to carefully monitor this software. I would recommend not in-stalling Java unless specifically needed. Several Or-ganizations just install Java by default on their base golden image which is distributed to all users. Unin-stall Java (or disable the plug-in if you need Java in-stalled) and youre less at-risk of zero-day attacks. Flash Player and Internet Explorer are less vulnerable than Java, make sure you have the latest versions run-ning and keep an eye on the updates and Patches.

2. Real-Time Protection IPS: Intrusion Prevention Sys-tems are not a luxurious option now but a must, espe-cially for large enterprises or Organizations dealing with sensitive data. The IPS solution should provide full protection that includes network-level protection, application integrity checking, application protocol Request for Comment (RFC) validation, content vali-dation and forensics capability.

3. Advanced Persistent Threats (APT) devices: There are several products on the market that provide compre-hensive protection against APT and Zero-Day attacks as FireEye, Symantec and HP TippingPoint. These devices protect against malicious web based attacks, email based attacks, block call backs from your inter-nal network and any other suspicious behavior.

4. IPSEC and Encryption: Applying IPSEC and ensuring all date is encrypted on transit and when transmitted across the internet. Encryption on rest and Transit should be in place, if possible.

5. Software Restriction Policy: Only needed and required software should be used. The more software and ser-vices you have on your system increase the attack sur-face and increase the opportunities of hidden vulnera-bilities. Systems exposed directly to the internet or on your DMZ should be hardened with minimum number of services running. Software Restriction Policies should be in place to restrict running software against the organization policy as browsers, plugins and un-controlled software.

6. Advanced Antivirus Heuristics: Normal antiviruses based mainly on signatures wont be efficient for such attack since it is not known and there is no publicly available signature for this attack. New Antivirus en-

Fig 2 Volume of Zero-Day Vulnerabilities 2006-2011, Source: http://www.symantec.com/threatreport/topic.jsp?

id=vulnerability_trends&aid=zero_day_vulnerabilities

eleven exploits (11) in the first quarter only of 2013. A full report for 2013 is not yet published. The main concerns by both reports are that these attacks cover a wide range of applications as Oracle Java of course, Microsoft Internet Ex-plorer, Adobe Flash and Adobe PDF. This is large number of attacks/vulnerabilities compared to previous years as shown below. The Most vulnerable and targeted application is Oracle Java. Its widely installed on millions of computers and its not peri-odically or automatically updated on most systems. The below figure from Kaspersky Labs show the percentage of threats on various applications and malware evolution in the first half of 2013.

Fig 3 Malware Evolution in 2013 Zero-Day Attacks, Source:http://www.securelist.com/en/analysis/204792316/

Kaspersky_Security_Bulletin_2013_Malware_Evolution#_Toc373346266

The most interesting part with these numbers is the business done with this Zero-Day vulnerabilities, there are very specif-ic organizations searching and looking for unknown vulnera-bilities to sell them to any willing buyers to use them in any manner. The prices for such vulnerabilities is quite high as per the below table.

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tensive test on new software or application or software ven-dor who discovered a flow or a problem in their software ? I believe there is an ethical social responsibility to disclose this to enable the Vendor to create a fix for it and for the end user. The public need to be aware of such threat. There are several events and conferences that encourage developers, testers or Ethical Hackers to discover and dis-close these vulnerabilities as Pwn2Own or Googles Chrome bug bounty program. They reward hackers for dis-covering and responsibly announcing these threats. If its discovered by the Software vendor or application owner then its his responsibility to patch/fix it as soon as possible and inform the public to patch their systems. During 2013 there has been several blogs and discussions over the internet discussing some NSA (National Security Agency) Servers codenamed FoxAcid. These servers have a wide-ranging menu of software exploits (Not known or publicly disclosed) at its disposal to tailor the right attack to the tar-gets it wants to monitor. These servers traps their targets to connect to them by any mean (Program, website, email linketc.) and then they can know everything about this system software and applications used and pre-pare/Launch the appropriate exploit when needed. For more information you may check this interesting article http://arstechnica.com/security/2013/10/nsa-saves-zero-day-exploits-for-high-value-targets/

This raised the question of how ethically should we do this? Is it something acceptable? Is it allowed for issues related to National Security? Are these Customers or organizations aware that they purchased a software with unknown vulner-abilities?

Conclusion Zero-day attacks have been around for long time and will continue to be there since humans make software and there will always be errors. They are very difficult to prevent be-cause of their nature and being unknown vulnerabilities where there is not any patch or ready-made fix or even anti-virus signature or firewall rule to detect it. However, reputation-based technologies, which assign a score to each le based on its prevalence in the wild and on a number of other inputs can detect events such as zero-day attacks and can reduce the effectiveness of the exploits. Al-so the security professional communities and ethical hacker should collaborate more efficiently to prevent such threats.

Biography:

Ahmed Nabil is an IT professional with more than 14 years of experience, special-ized in IT infrastructure, security, system administration and IT management. Ah-med real passion is Networking and Secu-rity. Ahmed hold a BS, MS, MCITP, MCSE, CCNP, CWSP, CEH, CHFI, ITIL and PMP. Ahmed has been recently

awarded the Microsoft Most Valuable Professional (MVP) award in Enterprise Security You can follow Ahmed on his blog (http://itcalls.blogspot.com)

gines with Heuristics that detects any suspicious activity or behavior can block or warn the administrator for this behavior for further analysis. Most of these Zero-Day attacks will exploit the vulnerability to run a malware or inject a virus and these type of activities can be detected by advanced Antivirus with Heuristics.

7. Keep all Software Updated: Most administrators update the main famous software as Microsoft, Oracle...etc. by following their update Cycle. For Example Microsoft has an update cycle called Patch Tuesday where Mi-crosoft release its updates on the second Tuesday of eve-ry month. Oracle do the same but quarterly. Admins tend to miss other critical software as Adobe, Java, apple, Mozilla...etc. There are different software available in the market to check all software for regular updates as SolarWinds Patch Manager which checks and updates Microsoft Products and other 3rd party products. This will not prevent Zero-Day attacks and that is why it is listed as the last technical protection mechanism. How-ever it will ensure you have the patch as soon as its available from the vendor.

8. Incident Response Plan: With all previous protection measure, there is always a possibility of a Zero-Day at-tack. A well-defined incident response plan with clear responsibilities and team roles with given procedures and policies will ensure fast recovery and problem isolation.

Ethical Responsibility and Disclosure Zero-Day attacks are discovered by either the dark side at-tackers or Hackers. Those are out of our control as their inten-tions are mainly bad and they will intend to exploit these vul-nerabilities to attack and hack systems to gain access for whatever reasons. Sometimes the hackers who discover these vulnerabilities sell it to other companies (This is huge busi-ness running nowadays). I would fully consider this as an or-ganized crime. What about Zero-Day attacks that are discovered by the good and normal guys as the end-users, testing teams running in-

Fig 4: Forbes Sources Price List 0-day vulnerabilities Source:http://resources.infosecinstitute.com/a-world-of-

vulnerabilities/

Modular Switched Mode Power Supplies (Rectifiers), Compared to convention Transformer/rectifiers

AbstractEfficient conversion of electrical power is becom-ing a primary concern to companies and to society as a whole. Switching power supplies offer not only higher efficiencies but also offer greater flexibility to the designer. Recent ad-vances in semiconductor, magnetic and passive technologies make the switching power supply an ever more popular choice in the power conversion arena today.

I. Introduction Historically, the linear regulator provides the desired output voltage by dissipating excess power in ohmic losses (e.g., in a resistor or in the collectoremitter region of a pass transistor in its active mode). A linear regulator regulates either output voltage or current by dissipating the excess electric power in the form of heat, and hence its maximum power efficiency is voltage-out/voltage-in since the volt difference is wasted. In contrast, a switched-mode power supply regulates either output voltage or current by switching ideal storage elements, like inductors and capacitors, into and out of different electri-cal configurations. Ideal switching elements (e.g., transistors operated outside of their active mode) have no resistance when "closed" and carry no current when "open", and so the converters can theoretically operate with 100% efficiency (i.e., all input power is delivered to the load; no power is wast-ed as dissipated heat).[1]

II. Comparison between convention Transformer/ RECTIFIERS AND high frequency power sup-plies (Switch mode power SUPPLIES)

Transformer/Rectifier set T/R In traditional transformer/rectifier sets, the line frequency sig-nal is fed into the high voltage transformer and thereafter rec-

tified before supplied to load If the input line feed is 3 phase 50 Hz, the resulting high voltage signal is a DC superimposed a 300 Hz ripple. This ripple represents one of the main disadvantages with the T/Rs. The list below points out some of the disad-vantages[2]: T/R is large in size and weight and will require special care in plant construction

T/R may contain large dielectric volumes requiring spe-cial precautions against oil spills.

Low power factor (0, 65 - 0, 75) Low power efficiency (0,75 0,85) Even with these significant negative effects, the T/Rs have definitely also positive sides Technology well suited for cost efficient re-

sizing/scaling Simple and well proven technology Well understood technology by relevant user groups High reliability in practical applications Proven to be cost efficient in many applications

Switch mode power supplies - SMPS In a switched mode power supply, the line frequency is rec-tified to a DC before converted to a high frequency AC sig-nal in a power electronic inverter. The AC signal is fed into a high voltage transformer and thereafter rectified be-fore supplied to the load.

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Figure 5: Modular high voltage SMPS basic module with HV cascade

III. Modular Switched Mode Power Supplies The Modular Switched Mode Power Supplies concept is a true modular concept, in that the desired output voltage is achieved by cascading high voltage transformers, and the desired output power is achieved by connecting the re-

quired number of modules in parallel. By connecting high voltage transformers in a cascade con-figuration, it will increase the output voltage to the desired level

The operating frequency of SMPS will normally be in the area 20-50 kHz resulting in a very low ripple in the rectified signal. The relation between ripple amplitude and frequency is de-fined by the following equation:

Equation (1)

Wheref is the switching frequency and C is the capacitance in the load connected to the SMPS. So, the ripple amplitude is inverse proportional with the switching frequency. Compared with a line frequency 3 phase T/R, feeding a 300 Hz ripple into the load, an SMPS with a switching frequency of 30 kHz, feeding a 60 kHz ripple into the load, will according to equa-tion (1) have a ripple voltage amplitude 200 times lower. Again, this will dramatically affect the average voltage level of the load and thereby the potential cleaning efficiency [3]. Since the SMPS operates on high frequencies there is a low requirement for energy storage internally in the transformer. Consequently, the size of the high frequency high voltage transformer may be dramatically reduced compared to the tra-ditional T/R. Hence, the total size and weight of the SMPS will be relatively small and accordingly also with a relatively

small dielectric volume. Based on the above, the main disadvantages with the SMPS technology as follows:

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With SMPS technology, its compact size and lighter weight enable users to make better use of space, which may be limited at remote sites. Switched-mode rectifiers are easier and less costly to install than T/R chargers and enable the consolidation of multiple power conversion products into an integrated dc power system

V. References 1) Pressman, Abraham. Switching power supply design.

McGraw-Hill, Inc., 1997. 2) Billings, Keith H., and Taylor Morey. Switchmode pow-

er supply handbook. Vol. 2. New York: McGraw-Hill, 1999.

3) Full scale test with Switched Mode Power Supplies on an ESP at high resistivity operating conditions, Reyes, Lund, ICESP VIII, 2001

Biography:

Mohamed El-Nady: PGESCo Electrical Engineering Group Leader. He received the B.Sc. degree in Electrical Power Engi-neering from Ain Shams University in 2006.He is interested in DC and UPS sys-tem design.

Once we have established the desired output voltage by adding elements to the high voltage cascade chain, we may introduce the final dimension in the modular concept, de-ciding the output power rating. This is simply achieved by connecting the required number of basic modules in paral-lel feeding the same load [2]

Figure 6: The full modular high voltage SMPS concept with multiple modules in parallel

IV. Summary This article has presented the benefits of SMPS technology for industrial battery chargers (Rectifiers). T/R battery chargers are used extensively for power stations; for oil and gas exploration and distribution; for maritime applications and many others. In each instance, the SMPS alternative offers significant benefits.

The traditional approach of using T/R chargers has worked well for many years. But each opportunity to add or replace a battery charger should be viewed as an opportunity to put in place the infrastructure for the next several decades. SMPS technology improves reliability and allows for re-dundancy where it was previously impractical. It offers sig-nificantly reduced energy consumptiona goal that will likely be important to us well into the future.

FORWARD DYNAMICS MODEL FOR DESIGNING LARGE-SIZE WIND TURBINE BLADES

1- Abstract In this paper, the Blade Element Momentum (BEM) theo-ry is used to design the horizontal wind turbine blades. The design procedure concerns the main parameters of the axial/angular induction factors, chord length, twist/attack angles, and local power/thrust coefficients. These factors in turns affect the blade aerodynamics characteristics and efficiency at the corresponding nominal speed. NACA 4-digits airfoil geometry is obtained, using BEM theory, to achieve the maximum lift to drag ratios. The optimization of the power coefficient and its distribution versus differ-ent speeds is carried out by modifying the twist angle and chord length distribution along the blade span. The dy-namic characteristics of both the original and optimized design are examined through forward dynamic simulation of the blade model. Since large-size wind turbine blade is considered, the dynamic model is established using the Absolute Nodal Coordinate Formulation (ANCF), which is suitable for largerotation large-deformation problems. Fi-nally, in order to verify the dynamic enhancements in the Aerodynamic/Structural properties, the fluid-solid interac-tion simulation for both the original and optimized model is performed using ANSYS code. The obtained results show a good rank of the proposed optimization procedure for a practical case of wind data upon Gulf of Suez-Egypt. Keywords: Absolute Nodal Coordinate Formulation, Mul-ti-body dynamics, Wind Turbine Blade, Optimization.

2- What is the problem? In the case of large-size wind turbine blades, the mass of the blade is said to increase proportionally with the blade size . The gravitational and centrifugal forces become critical due to blade mass. To counteract the weight increase, the de-velopment of blades goes towards long and relatively flexi-ble structures. It is obvious that the design process of such large-size should be based on accurate dynamic modeling of such blades and precise models of aerodynamic loads. Fur-thermore, the dynamic model will be used for analysis, iden-tification and monitoring process. It is found that the incre-mental finite element method can be used in modeling wind turbine blades in case of relatively flexible blades (small deformations), for buckling loads, transversal mode shapes

and frequencies. The main goal of this work is to give the answer of why/why not the ANCF is suited for modeling large-size wind turbine blade application. And how to incorporate it with the wind turbine performance analysis through a for-ward dynamics design process to enhance its structural properties and performance.

3- Why we study this problem? For accurate design process; it must considers:

The blade flexibility. Large-rotations and large deformations load cases. Fluid structure interaction. WT performance calculation.

Combining these factors together through a design process, is a necessary step for :

Selecting appropriate materials which enables the blade to work under many operating and occasional load cases.

Making the WTB aerodynamics, structural and perfor-mance characteristics become more efficient.

Studying more static and dynamic load case combina-tions where the large rotation and large deformation scenarios are considered.

Figure 1: The proposed WTB design work process.

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Figure 4: 12-Elements complete non-uniform WTB [2]

3- ANCF; Plate element It is found in the literature [Shabana et.,al], that the ANCF is very suitable for modeling large-deformation, large-rotation structures, which is the case of large-size wind turbine blades. The real geometry of the wind turbine blade (WTB) is non-uniform and twisted. For 4-noded plate element, 12 nodal coordinates are used/node. The nodal coordinate vector of node 1 is: [1]

Figure 2: Plate Element

The nodal coordinates of an element e is by :

in Bayoumy A. H. et al. 2012, The non-uniform wind tur-bine blade was modeled by ANCF using lofting, and slope discontinuity problem was manipulated successfully.

Figure 3: Thin plate element

T1T 1T 1T

T1 1T 1T 1T 1T 1T

x y zx y z

r r r

r r r r re

T1T 2T 3T 4T e e e e e

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Figure 6: a preliminary and optimized WTB models

5- Forward dynamics model The dynamic modeling of large-size wind turbine blades using the ANCF can improve the design process of such blades. The dynamic characteristics help to predict the dy-namic loading capacity and energy losses. These two fac-tors affect, in turns, on the rotor torque, the output power and consequently the blade efficiency. To optimize the power extracted by the WTB then the power coefficient of the WTB must be optimized to its maximum value to meet the site conditions and achieve a good distribution with different wind speeds. Using the preliminary input data in Table 1 except the chord and twist distribution stated method. The WTB is divided into 30 elements. The objec-tive is to maximize the output power P at a nominal steady wind speed by the variation of the chord length distribu-tion and twist angle along the WTB span elements. As-sume the chord length changes non-linearly in a 2nd order relation with the local Speed ratio [3]

Figure 5: Forward dynamics and optimization process

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Blade [3-4]. The ultimate static test is carried out by pull-ing a blade to failure point.Three static tests will be inves-tigated to express the advantages of use the ANCF in mod-eling large-size wind turbine blades. In ANSYS, the static analysis can be performed by replacing the transient- structural module by statics-structural module.

6- Large-Deformations problem : Static loading test In the static test, which is required as part of blade certifi-cation, the blade is pulled in the horizontal or vertical axis, flap-wise in order to measure blade deflection. Static test-ing will be performed with a combination of computer controlled servo-hydraulic winches and cylinders connect-ed through cables to the

Figure 8: Simulation results of static loading test [4]

Figure 7: Static hydraulic load test

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Author Bibliography

Ahmed H.Bayoumy : He received the B.SC

degree in power Mechanical Engineering

from Benha University in 2008. He is pursu-

ing the M.Sc degree on Modeling, Simula-

tion and optimization of the Large-size Wind

turbine Blade Using ANCF at Cairo University.

1- A Continuum Based Three-Dimensional Modeling of Wind Turbine Blades Ahmed H. Bayoumy, Ayman A. Nada and Said M. Megahed, ASME, J. Comput. Nonlinear Dynam. 8, 031004 (2012) (14 pages); doi:10.1115/1.4007798.

http://computationalnonlinear.asmedigitalcollection.asme.org/article.aspx?articleid=1694110 2- Modeling Slope Discontinuity of Large Size Wind-

Turbine Blade Using Absolute Nodal Coordinate Formu-lation, ASME Proceedings | 1st Biennial International Conference on Dynamics for Design, Paper No. DETC2012-70467, pp. 105-114; 10 pages doi:10.1115/DETC2012-70467.

http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1736660 3- USE OF FORWARD DYNAMICS MODEL FOR DE-

SIGNING LARGE-SIZE WIND TURBINE BLADES Ahmed H. Bayoumy, Ayman A. Nada, Said M. Mega-hed.Proceedings of the ASME 2013 International Mechan-ical Engineering Congress and Exposition IMECE2013 November 15-21, 2013, San Diego, California, USA.

http://asme.pinetec.com/imece2013. 4- Methods of Modeling Slope Discontinuities in Large-

Size Wind Turbine Blades Using Absolute Nodal Coordi-

nate Formulation Bayoumy, Ahmed, Nada, Ay-

man and Megahed, Said. SAGE, Journal of Multi-body Dynamics. Accepted, publication in progress.

Conclusions and discussions WTB main parameters are modeled using BEM theory to meet the site conditions, such parameters are introduced as the main inputs to an efficient forward dynamic modeling procedures . Since the ANCF is suited for large-deformation, large-rotation problems, which is the case of large blades, consequently, the use of ANCF opens oppor-tunities to improve the design process of such blades. The design process of the large size WTB must considers:

Blade flexibility where the large rotations large defor-

mations problem may arise at the large loading scenarios.

the FSI interactions between aerodynamic characteris-tics and the blade flexible structure; which is represented in modeling the aerodynamic forces and study its effect on the blade.

WTB performance which is highly dependant on the site conditions and the blade geometry.

Recommendations It is found that In order to improve the dynamic simulation

results; it is suggested to increase the number of elements

along span length. Wind turbine blade made of composite

materials, making them anisotropic, which increase the in-

ternal elastic coupling effect of blade motion. This cannot be

described by the moving frame of reference, especially with

high rotating speeds. Therefore, ANCF helps in modifying

them. Considering different airfoil families and codes selec-

tion along the wind turbine blade span in the optimization

process to enhance the wind turbine blade performance.

lower tip speed results in higher wake swirl losses, so the

effect of the tip speed on the wakes must be considered in

the design process .

Static load cases Load location from the root (m) Applied load

(KN)

Tip deflection (m)

SAMS2000 ANSYS.

Load case I

5 0.11666

1.358 1.4257 10 0.11666

15 0.11666

Load case II

5 0.33

4.537 Non-convergent solution 10 0.33

15 0.33

Load case III

5 3.33

15.68 Non-convergent solution 10 3.33

15 3.33

HV Shunt Reactor Protection

Abstract- Shunt reactors are applied to long, high-voltage transmission lines to offset the impact of line charging capacitance to prevent high voltage during lightly loaded conditions. Shunt reactors are important assets and demand a robust protection scheme to safeguard them from abnormal operating conditions. The article provides back-ground information on HV shunt reactor applications and types applied on high-voltage transmission systems. It dis-cusses High voltage shunt reactor characteristics that are relevant to protection. Finally it provides a practical exam-ple for protection applied on the EHV (400 KV) Shunt Re-actors of Iraq-Baiji Power Plant.

I. Introduction A. Need for Shunt Reactors HV shunt reactors are the most compact and cost-efficient means to compensate reactive power generation of long-distance, high-voltage power transmission lines, or extend-ed cable systems during light load conditions. Two main application of the reactor can be identified as:

Shunt reactors that are continuously in service, generally used for EHV and long HV lines/cables.

Switched shunt reactors are applied in the underlying system and near load centers.

B. Shunt Reactor Connections to High-Voltage Transmis-sion Systems

High voltage shunt reactors are normally connected to pow-er system in three locations (see Figure 2). They can be connected to Line, Bus or Tertiary winding of the power transformer or auto-transformer. The line connected reactors are normally connected at both ends of the line as each end can be energized or de-energized independently. The shunt reactors can be con-nected directly to HV lines or via circuit switcher or circuit breaker to HV lines or buses depends on the application. The permanently connected reactors are used to prevent overvoltage appear on long lines due to lightly loading or open circuit. The switched reactors are used for voltage control. These reactors are normally grounded, solidly or via a neu-tral reactor. The neutral reactor is used where single pole auto-reclose is applied, to suppress the secondary arc cur-rent.

II. Shunt Reactor Types The two general types of construction used for shunt reac-tors are dry-type and oil-immersed. The following types of shunt reactors are employed for high-voltage transmission line applications:

A. Dry-Type Dry-type shunt reactors are generally limited to voltages through 138 kV and can be directly connected to a trans-mission line or applied on the tertiary of a transformer that is connected to the transmission line being compensated. Dry-type reactors are air cooled and constructed as single-phase units mounted on insulating support structures and sufficiently spaced to prevent the magnetic fields from in-dividual units from interacting with each other. Due to the

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Practical Example on EHV (400 KV) Shunt Reactors

Of Iraq-Baiji Power Plant

absence of an iron core, they are not affected by saturation and inrush.

B. Oil-immersed The two design configurations of oil-immersed shunt reac-tors are coreless type and gapped iron-core type. Both de-signs are subject to low-frequency long time-constant cur-rents during de-energizing, determined by the parallel com-bination of the inductance of the reactor and the line capac-itance. However, the gapped iron-core design is subject to more severe energizing inrush than the coreless type. Most coreless shunt reactor designs have a magnetic circuit (magnetic shield) that surrounds the coil to contain the flux within the reactor tank. The steel core-leg that normally provides a magnetic flux path through the coil of a power transformer is replaced (when constructing coreless reac-tors) by insulating support structures. This type of construc-tion results in an inductor that is linear with respect to volt-age. The magnetic circuit of a gapped iron-core reactor is con-structed in a manner very similar to that used for power transformers with the exception that small gaps are intro-duced in the iron core to improve the linearity of induct-ance of the reactor and to reduce residual or remanent flux when compared to a reactor without a gapped core. Oil-immersed shunt reactors can be constructed as single-phase or three-phase units and are very similar in external appear-ance to that of conventional power transformers. They are designed for either self-cooling or forced-cooling.

III. Reactor Operating Characteristics A. Linearity Fig. 5 shows the magnetizing characteristics of both gapped iron-core and air- core shunt reactor designs. For a gapped iron-core reactor, the current displays a linear rela-

tionship with the applied system voltage until a knee point voltage is reached. Beyond the saturation point, which is determined by the knee-point voltage, the gapped iron core becomes saturated and the current is nonlinear with the operating voltage.

On the other hand, for an air-core reactor of either dry-type or oil-immersed construction, no saturation of the core occurs due to the absence of an iron core, and the cur-rent increases linearly with voltage, as seen in Fig. 5.

B. Shunt Reactor Energization

1. Inrush Phenomena The energizing of a shunt reactor will, to some degree, be-have in the same way as energizing of a power transformer. There will be a transient inrush current. Due to the air gap, the reactor core keeps no remanence. This makes the inrush phenomena smoother. However, the damping of the inrush current is slow due to the low losses in the shunt reactor. Therefore the primary current might have, long lasting dc component. The presence of dc component with long time constant might lead to saturation of the CT some periods after energizing of the reactor.

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2. Shunt Reactor Problem As shown in Fig. 10 the relatively small, but persistent DC currents in primary currents can sooner or later drive the current transformers into saturation. If the current trans-former on the other side of the reactor does not saturate at exactly the same instant, and to the same degree, the false differential currents may be high enough to cause an unwanted disconnection, The problem is that the fundamental frequency currents which flow in-to the reactor after its connection to the voltage source are not much above the normal load cur-rents. The differential protection is thus waiting for any differential currents at its best (highest) sensitivity in section-1 of the operatebias charac-teristic. The danger of an unwanted operation is imminent!

C. Harmonics content Steady state harmonics in reactor current arise from partial saturation in the magnetic circuit. These effects are in fact very small, and without practical importance for relaying and communication interference. Of all harmonics the 3rd harmonic is the dominant harmonic in shunt reactors during normal operating condition, due to asymmetries in the reac-tor windings. The 3rd harmonic can be seen in the neutral point of the shunt reactor or as residual using all phases

D. Shunt Reactor behavior during external and internal faults

Shunt reactors are connected in parallel with the rest of the power network. Shunt reactor can be treated as a device with the fixed impedance value. Therefore the individual phase current is directly proportional to the applied phase voltage (i.e. I=U/Z). Thus during external fault condition, when the faulty phase voltage is lower than the rated volt-age, the current in the faulty phase will actually reduce its

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value from the rated value. Depending on the point on the voltage wave when external fault happens the reduce cur-rent might have superimposed dc component. Such behav-ior is verified by an ATP simulation and it is shown in Fig-ure 6.

As a result, shunt reactor unbalance current will appear in the neutral point as shown in Figure 7. However, this neu-tral point current will typically be less than 1 pu irrespec-tive of the location and fault resistance of the external fault.

Similarly during an internal fault the value of the individual phase currents and neutral point current will depend very much on the position of the internal fault. Assuming that due to the construction details, internal shunt reactor phase-to-phase faults are not very likely, only two extreme cases of internal phase to ground fault scenarios will be presented here. In the first case the Phase A winding to ground fault, 1% from the neutral point has been simulated in ATP. As a re-sult the phase currents on the HV side (i.e. in reactor bush-ings) will be practically the same as before the fault as shown in Figure 8.

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ues somewhere in the range limited by this two extreme cases.

IV. Shunt Reactor Protections A. Typical Protection Configurations Major fault protection for dry-type reactors can be achieved through overcurrent, differential, or negative se-quence relaying schemes, or by a combination of these relaying schemes. Protection for low-level turn to-turn faults can be provided by a voltage-unbalance relay scheme connected at the neutral with compensation for inherent unbalance of system voltages and the tolerances of the reactor.

Major fault protection for oil-immersed reactors can be achieved through overcurrent relaying, differential relay-ing, or a combination of both. Protection for low-level turn-to-turn faults can be provided by impedance, negative or zero-sequence overcurrent, thermal, gas-accumulator, sudden-pressure relays, or by a combination of these re-lays.

B. The survey of the philosophy for shunt reactor differ-ent protection functions can be summarized as follows:

Phase differential function detects all types of shunt faults but has no possibility to detect turn-tum faults. It can be set quite sensitive due to a fact that there is no need for bias-ing. The need for phase differential protection for a given reactor depends on reactor size and importance of the unit. Restricted earth fault protection operates for all types of faults that give zero sequence current. It is used in applica-tions where the star connection is done internally in the reactor. It can be set very low, but consideration of the er-ror in the comparison of the summarized phase currents and the neutral current should be considered. Phase overcurrent protection is used as backup for the phase differential protection or as main protection for phase-phase faults when restricted earth fault protection is only used. Phase overvoltage protection is sometimes used to detect line overvoltage conditions that may cause damage to the reactor when it operates at higher voltage levels than the reactor rated voltage. Consultation with reactor manufac-turer is needed. A more common use is to monitor the volt-age on the system and to energize the reactor at a pre-defined "overvoltage level". If the reactor is already ener-gized at the same time as the overvoltage level is activated, the overvoltage function can be used to protect the system from dangerous overvoltage i.e. disconnect the line and reactor. Zero sequence overcurrent protection that measures the neutral point current can be used as a system backup pro-tection with low setting and longtime delay. If the current is combined with measuring the zero sequence voltage, a sen-sitive backup protection for internal faults can be achieved.

However phase A current at the shunt reactor star point and common neutral point current will have very big value due to so-called transformer effect. These currents can be so high to even cause CT saturation as shown in Figure 9 for the common neutral point current

This type of the internal fault shall be easily detected and cleared by the differential, restricted ground fault or neutral point ground overcurrent protection, but not by reactor HV side overcurrent or HV residual ground fault protections. In the second case the Phase A to ground fault, just be-tween the HV CTs and shunt reactor winding (i.e. shunt reactor bushing failure) has been investigated. In this case the currents have opposite properties. The phase A current on the HV side is very big (limited only by the power sys-tem source impedance and fault resistance), while the phase A current in reactor star point will have very small value due to a fact that phase A winding is practically short-circuited. As a result, shunt reactor unbalance current will appear in the neutral point. However, this neutral point cur-rent will typically have a value around 1 pu (i.e. similar value as during external ground fault). That type of the internal fault (i.e. shunt reactor bushing failure) shall be easily detected and cleared by the differen-tial, restricted ground fault or HV side overcurrent or resid-ual ground fault protections. Neutral point ground overcur-rent protection can operate with the time delay. For internal ground fault in some other location in-between these two positions the shunt reactor currents will have val-

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B. Protection settings calculations philosophy 1. The first step is to ensure that the CTs have been properly

sized. A proper CT is one that is sized to ensure proper operation of the associated relays for faulted conditions and to ensure that the relays do not mal operate for exter-nal faults. The current transformers adequacy will be checked using equation (1) which states that if Vs is less than 20, the CT does not go into saturation.

Where: Is:The current in per unit of the tapped CT primary rating. ZB:The CT burden in per unit of tapped standard burden. X/R: the X/R ratio of the circuit driving the current IS.

Vs: The per-unit saturation voltage. The main factors that affect the evaluation of Vs are Is multiplied by ZB, which is the voltage developed by the CT to drive ratio current through the connected burden circuit, and the X/R ratio, which affects how quickly the dc offset decays and the current becomes symmetrical. In most protection application cases, we use this equation to evaluate the performance of the CT for high-current faults. In the reactor application case, the current of interest is the reactor rated current, so it is relatively low.

2. There is no dedicated numerical relay built to protect a shunt reactor. Because most of the protection functions implemented in shunt reactor protection are readily avail-able in a transformer protection relay. Generally the dif-ferential protection device used for shunt reactor is the same as for power transformer.

No need for vector group correction

No need for zero sequence current elimination

The inrush currents are measured on both sides and should theoretically not be seen by the protection as a differential current.

3. The Shunt Reactor protection scheme uses a low-impedance percentage differential relay. This element operates on a slope characteristic based on the ratio of the operating current to restraint current. In the low imped-ance principle the CTs are of different ratio. Ratio match-ing is performed by numerical relay software.

4. The percent differential pickup is the amount of differen-tial current that might be seen under normal operating conditions to account for CT inaccuracies and current variation due to CT ratio mismatch, CT accuracy error, and Shunt Reactor excitation current.

5. The differential slope setting is to prevent maloperation due to false differential currents on CT saturation during high-grade through faults and during normal operation. A reactor does not experience a high-grade through-fault current because a fault on the line causes voltage depres-sion and the current through the reactor is relatively less than the rated current. So, the slope setting is not as sig-

C. Turn-to-Turn Fault Protection Detecting turn-to-turn faults in a reactor using electrical measurements is extremely difficult. For oil-filled reactors, the sudden pressure (63) and Buchholz (71G) relays pro-vide mechanical protection for these types of faults. Sensi-tive electrical protection for these faults is recommended and is necessary for dry-type reactors.

D. Mechanical Protection Devices Similar to the power transformers, the mechanical protec-tion and monitoring devices available for shunt reactor protection are usually provided as a built-in option in oil-immersed reactors. For instance, sudden pressure relays (63) and gas accumulation relays (71G Buchholz relays) provide sensitive detection of low-grade internal faults, es-pecially turn-to-turn faults, (71Q) low oil level relays can be applied to indicate if the oil level falls below a predeter-mined minimum level. (80Q) indicates a failure of oil cir-culation to cooling circuits. These mechanical relays pro-vide excellent complement to the electrical protection ele-ments previously explained. It is recommended to arrange that these mechanical relays trip reactor circuit breaker independently from electrical relays. However signals from mechanical devices shall be connected to binary inputs of numerical relays in order to get time tagging information, disturbance recording and event reporting in case of their operation.

V. HV Shunt Reactor Protection Example In previous sections we discussed the purpose, use, types, and characteristics of high-voltage shunt reactors. In this section the article describes the protection scheme provided for EHV (400 KV) Shunt Reactors of Iraq-Baiji Power Plant.

A. Iraq-Baiji Power Plant EHV (400 KV) Shunt Reactors In this power plant project, three units of 3-phase shunt re-actors connected at the end of three long overhead trans-mission lines at Baiji power plant 400 KV Switchyard in addition to three 1-phase neutral grounding reactors. For typical connection between one LSR and NGR with OHTL and 400 KV GIS refer to Figure 12. The following table gives technical data for both reactors:

Table I: Iraq-Baiji Power Plant 400KV Shunt Reactor and Neutral Grounding Reactor technical data.

Data Line Shunt Reactor (LSR)

Neutral Grounding Reactor (NGR)

Type 3-Phase oil immersed gapped-iron core

1-Phase oil im-mersed gapped-iron

core Rated Power 50 MVAR 600 KVAR

Rated Frequency 50 Hz 50 Hz

Rated Voltage 400 KV 60 KV Rated Current 72.2 A 300 A /10 sec Vector Group YN ---

Cooling Method ONAN ONAN

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Note: These protection settings shall be revised for solidly grounded oil immersed shunt reactors connected to OHTL through HVCB.

nificant as it is in transformers, and the Slope 1 and Slope 2 settings can be left at the relay default values.

6. Inrush current in a shunt reactor doesnt appear as a differ-ential current like that which appears in a transformer, un-less the CT saturates after some time due to long DC time constant. Though the level of second harmonic in many cases can be relatively high there are many cases with no or very low content of harmonics. The level of 2nd har-monic is small in shunt reactors compared to transformers.

7. In order to avoid unwanted tripping of low impedance dif-ferential protection during Shunt Reactor energization the following methods might be used:

2nd harmonic blocking/restraint feature in combination with cross blocking functionality.

Adaptive DC biasing. The 2nd harmonic restraint feature is often available in low

impedance differential protection applied to shunt reac-tors. This may offer additional protection improvements in some cases. For numerical low impedance differential protection a setting of the 2nd harmonic blocking function as low as 10%, may prevent the restrained differential function from undesired operation during reactor energiz-ing.

8. Multifunctional numerical relays provided with an addi-tional high level unrestrained differential function to offer secure and fast tripping for such internal faults with high magnitude fault currents. The instantaneous differential element acts as an instantaneous overcurrent relay re-sponding to the measured differential current magnitude. It should be used in order to secure a fast fault clearance.

9. Multifunctional numerical relays utilize Digital Fourier Filtering (DFF) technique which effectively suppresses the dc component of the measured input current. Therefore protection functions settings can be set more sensitive.

C. Protection Settings Guidelines Summary Table II provides guidelines for shunt reac tor protection functions set t ings shown in (fig. 11).

TABLE II: Protection Settings Guidelines Summary

Func-tion Description

F87R, Phase Diff.

Diff. restrained pickup 10% of reactor rated current, Diff. pickup delay time setting = 0 sec Slope 1 and 2 = Relay default values Inrush 2nd Harmonic Restraint = 10%

Diff. unrestrained pickup 200% of react.rated cur-rent,

pickup delay time setting = 0 sec

F87N, REF

Pickup 10% of reactor rated current, Time delay 0.1 sec, Slope 20%

F50, Phase

OC

Pickup 150% of reactor rated current, pickup delay time setting = 0 sec,

Inrush 2nd Harmonic Restraint = 10%

F51N, Phase TOC

Pickup 150% of reactor rated current, Time Dial = 1,

IEC curve = Ext. Inverse

F50G, Ground

OC

Pickup 10 % of max. permissible ground current, pickup delay time setting = 2 sec (Definite Time)

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BIOGRAPHY:-

Alaa Abdou; He received the B.Sc. Degree in Electrical Power & Machines Engineer-ing from Cairo University in 2001. He has over 10 years of extensive work experience in various aspects of electrical power engi-

neering in industrial projects. in Egypt and Gulf area. Since he joined PGESCo he worked in Al-Atf, Sidi-Krir, Al-Shabab, Damietta and West Damietta power plants projects. At present he is working as Deputy Electrical Engi-neering Group Supervisor in Iraq-Baiji power plant project. He is interested in High voltage substations, medium and low voltage systems design.

Fig. 12: Real site photo of 400 KV Shunt Reactor of Iraq-Baiji Power Plant Project..

VI. CONCLUSION The article has highlighted some important issues of the applications of shunt reactors and their influence on the reactor protection scheme. Furthermore it provides the protection scheme applied on EHV (400 KV) shunt reac-tors of Iraq-Baiji power plant as a practical application example.

VII. REFERENCES

[1] IEEE Standard C37.109, IEEE Guide for Protection of Shunt Reactors.

[2] Cigre WG Report B5.37, Protection, Monitoring and Control of Shunt Reactors, August 2012.

[3] Carvalho, F., Fabiano L., Lidstrom S., Gajic Z., Saha M.M. Application of Numerical Relays for HV Shunt Reactor Protection , 2004 IEEE PES Transmission & Distribution Conference 8 Exposition Latin America.

[4] ABB Protection Application Handbook, Book No.6, Re-vision 0.

[5] ABB Power Technologies AB, Sweden. HV Shunt Re-actor Secrets for Protective Engineers, proceedings of the 30th Annual Western Protective Relay Conference, Spokane, WA, October 2003.

[6] Faridul Katha Basha and Michael Thompson, Schweitzer Engineering Laboratories, Inc. Practical EHV Reactor Protection.

[7] Ivo Brn i, Zoran Gaji, Stefan Roxenborg, "ADAPTIVE DIFFERENTIAL PROTECTION FOR GENERATORS AND SHUNT REACTORS.

[8] J. H. Harlow (ed.), Electric Power Transformer Engi-neering. CRC Press LLC, Boca Raton, FL, 2004.

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Tekla Engineers in the Civil-Designers Team: Sherif Hewaidy, Mohamed Khalil, Mamdouh Awad (EGS),

Mohamed Hassan & Mamdouh Saleh

Tekla Structures - Winner of Middle East 2013. Page.3

PGESCo Engineering Magazine Issue VIII Feb,2014PGESCo is the TeklaStructures - Winner ofMiddle East 2013Zero Day VulnerabilitiesModular Switched Mode Power Supplies(Rectifiers), Compared to conventionTransformer/rectifiersFORWARD DYNAMICS MODEL FORDESIGNING LARGE-SIZE WINDTURBINE BLADESHV Shunt Reactor Protection

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