O-Engineers Jan 2018

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O-Engineers

6th issue, Jan 2018 6th issue, Jan 2018 Learning and Guiding Learning and Guiding

DISTANCE RELAY INTERVIEW DISTANCE RELAY INTERVIEW

QUESTIONS QUESTIONS

(Page-15)

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CONENS

PAGE E

LET'S TALK

PAGE 1

FEEDBACK FEEDBACK

PAGE 2

FIELD DRYING OF OIL FILLED

FIELD DRYING OF OIL FILLED TRANSFORMERTRANSFORMER

PAGE 8

RESTRICTED EARTH FAULT RELAY

PAGE 15

DISTANCE RELAY INTERVIEW QUESTIONS

PAGE 23

BREAD WITHOUT BUTTER

PAGE 28

_E-_E-QUOTES QUOTES

PAGE 31

FINAL SEMESTER FINAL SEMESTER

PAGE 35

BOOK FOR THIS MONTH

PAGE 34

ENGINEER ENGINEER MAKING MAKING DIFFERENCE DIFFERENCE

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CONENS

PAGE E

LET'S TALK

PAGE 1

FEEDBACK FEEDBACK

PAGE 2

FIELD DRYING OF OIL FILLED

FIELD DRYING OF OIL FILLED TRANSFORMERTRANSFORMER

PAGE 8

RESTRICTED EARTH FAULT RELAY

PAGE 15

DISTANCE RELAY INTERVIEW QUESTIONS

PAGE 23

BREAD WITHOUT BUTTER

PAGE 28

_E-_E-QUOTES QUOTES

PAGE 31

FINAL SEMESTER FINAL SEMESTER

PAGE 35

BOOK FOR THIS MONTH

PAGE 34

ENGINEER ENGINEER MAKING MAKING DIFFERENCE DIFFERENCE

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Editorial

Let's talk

Te year 2017, what a year? we

did a lot, we got a lot, we lost a

lot, we moved ahead a lot, we

read a lot, we araid a lot, we

eel job insecurity a lot, we did

everything a lot,but the but the

journey still no

journey still not ends ant ends and stilld still

a lot is ahead o us. Te world

is changing in seconds, not in

hours or days, daily new android

apps are amazing us, Artiﬁcial

sofwares are playing with our mind in hidden robes, the terminology o

the Sof-knowledge worker is at the mirage o all time, everywhere there

is the race o knowledge gaining, one laptop with good wiﬁ connection

can make you the brilliant online consultant, tutor, engineer, manager

etc. old technologies are replaced by new technologies, Universities are

upgrading their educational system and companies are upgrading their

expectations rom degree holders. we Engineers need to be prepared or

this up-gradation i we are on another side(which is still stuck up with old

thoughts and technologies) then we Engineers will lose this race, ﬁnal year

students need to be more brilliant in simulation sofware i they want to be

an integral part o uture Sof-Knowledge based Organizations.

E E

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Feedback

Add mechanical

engineering topics also in coming editions.

(Engr. Naja ali)

Improvement is there, but need more eﬀorts in

developing a trend in engineering

(Engr. Sumaiyya Wajih) I liked the article "I Quit", yes it is quite an issue

nowadays, lot o consultants and individuals are making money rom Jobless and On-job

proessionals, and in many countries, there is no such law to grab such raudulent companies, good work team O Engineer, keep it up

(Engr. Mukesh Narayan) It is great to see Engr. Irn Akhter's

article about guideline or Chinese EPC in Dec edition, a good learning

(Engr. Fatah Ali Pasha)

Going good (Engr. Zain Noor)

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Field Drying of Oil Filled

Transformers

Engr. Iran Akhter

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H

aven’t written anything in a while. In this short

article, I have chosen an

important subject or clarity or my ellow engineers

esp in Pakistan. Why this subject now? Well, part o the reason is that we

bought a new oil treatment machine and the other

part is our interaction with clients during the marketing o our service. Tere are ew things which are not normally clear

to people working at the plants. I will address those issues here.

Question: Should I do dehydration at

an interval or on the need basis?

Well, you have to consider your maintenance strategy

or your transormers. I your oil breakdown voltage and moisture

contents are within

limits, you may not need dehydration o your

transormer or a while. Some people don't like doing it or the ear o

losing DGA history. Tey are not wrong.

You need a resh sample aferward to establish a baseline.

Te presence o moisture in a transormer

deteriorates transormer insulation by decreasing both the electrical and mechanical strength. In general, the

mechanical lie o the insulation is reduced by hal or each doubling in water content.

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Remember the main insulation and one that deﬁnes the lie o a transormer is its solid insulation: mostly paper and some wood. So you don't want to operate

your transormer near limits o moisture content. Limits are deﬁned in IEC 60422 or both moisture content and relative saturation (or the degree o wetness or oil and paper). Water saturation o insulating oil is also very useul or trending. Saturation is the ratio o the water content present in a mineral oil at a certain temperature to the solubility o water in mineral oil at the same

temperature, expressed in percent. It can be calculated rom known values, obtained by Karl Fischer titration or by on-line moisture sensors.

Water saturation

o insulating oil is

also very useul or

addition to BDV and calculate relative saturation and bring it below 5% as mentioned in the above table. It requires more time and good vacuum with heating o oil in the machine. A newer machine with no leaks and presence o a moisture sensor helps. As it takes more time, hence it is expensive as compared to usual 2 or 3 passes based on improvement in BDV alone.

Te eﬃciency o dehydration regardless o method depends on a number o actors, including the oil temperature and the degree o vacuum pulled. Te

challenge is to use a system that avoids use o excessive temperature, which promotes degradation o the

cellulose, yet brings about the removal o the maximum

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a degree o moisture rom the insulation. For eﬃcient dry out, a vacuum in excess o the equilibrium values is required. Te drying operation occurs when the oil-cellulose equilibrium condition is disturbed avorably. Other actors that determine the eﬃciency o water

removal include, an initial water content in the oil and in the cellulose, oil ﬁlm thickness, time o exposure to vacuum and accelerators, such as agitation. In the case

o just wet oil, or wet oil and wet windings, a couple o recirculations o the oil through a vacuum dehydration system will dry the oil. Te dry oil will be contaminated by the wet windings as they seek equilibrium condition, repeating this cycle many times can correct the

situation.

Question: Can an old, leaking and

contaminated machine poses a risk to my ransormer?

It surely poses a big risk. You can aerate your

transormer which will be cause o oxidation and hence reduce the lie o your transormer. A poorly maintained machine might introduce contaminants carried rom

other jobs like PCB or as worse as traces o Cu2S.

Question: I there is no leakage rom my transormer, where does the water come rom?

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Well, water in the transormer can come rom outside which remains the biggest source. It enters during

transormer manuacturing and transportation. In ree breathing transormer, a small amount o water enters into the transormer during breathing. But once you take a transormer in service, water is created

as transormer ages as a by-product. Presence o

high amount o water (moisture) accelerates urther production. It is a result o Pyrolysis, Hydrolysis, and Oxidation going on the oil/paper o transormer.

Question: Will the dehydration process

improve out o limit Oil power actor, IF and Acid Number?

End o lie (EOL) or transormer oil is based on the

limits o Oil Power Factor, Interacial ension and Acid Number. Once these values crossed the ﬁnal limits, no amount o dehydration can help restore oil insulation properties. One may consider regenerating oil or

replacing it altogether.

Question: I have a leakage where oil is

seeping out o transormer body, outside moisture cannot go in?

Tis is a wrong concept. I you have leaked rom

where oil comes out, moisture has a path to enter the transormer. So attend a leak as soon as possible.

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Restricted Earth

Fault Relay

Engr. Qazi Arsalan Hamid

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9

Objective: o understand the working principle o REF Relay

Power Equipment to be Protected: Power ransormer

Relay Used: 7PG23

Discussion: REF is employed basically on

transormer with vector group delta star, it is usually like Diﬀerential Protection o ransormer

In this we employed 1 Current transormer at star point o star-secondary point o ransormer, three current transormers with ring type connection is employed

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as per ﬁgure below.

In Ring Connection, the Principle o Current circulation is applied

Ia+Ib+Ic=0

and in star point o ransormer will be zero.

Te concept o high impedance and low impedance:

in high impedance REF relay, the star point o the

transormer must be equipped with internal or external resistor, the internal resistor must be located in high

impedance relay and external resistor will be

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provided outside relay.

in high impedance REF relay the ratio o Phase and neutral Cs must be same, but in low impedance REF relay it is not necessary, knee point voltage o high

impedance REF relay Cs must be same, stabilization the voltage o high impedance relay is another deciding actor in relay operation when a setting voltage is

equal to stabilization voltage relay not operate, but when stabilization voltage will higher than setting

voltage the relay operates.

in high impedance REF relay, we must provide Metal oxide varistor(MOV) or protection rom high

voltages surges, and i C ratios are diﬀerent then we employees the interposing Cs(auxiliary Cs) to

prevent spill current, in low impedance no such thing as interposing Cs required.

stabilization voltage=(Maximum ault current relay*Ct secondary resistance * lead resistance)/C urn

ratio

saety actor recommended is 2, Vk=2*Vsetting

Minimum primary operating current o Relay=C turn ratio*(Relay operating current*no: o

Cs*magnetization current o Cs*Varistor Current at Setting voltage)

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when the ault occurs outside the restricted area, the zero sequence o Red phase to earth still ﬂows through

Red and neutral Ct so new Relay not operates.

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in case o the internal ault, the equilibrium disturbed, and abnormal current o red to earth ﬂows through

C-neutral also, this result in relay operation.

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Example Working:

8 MVA transormer with Z=0.0835p.u,ap=+/-10%,CR=800/1 Location: Conﬁdential

Solution:

Fault MVA=8MVA/0.0835=95.8084 Fault Current Primary=(Fault MVA/ (1.732*6.6KV))*1000=8281.06A

in secondary, CR=800/1 and Fault Secondary Current=Fault maximum/C

Ratio=8281.06/800=10.4763A

Vs=Fault Secondary current*(Rct+RL)

since Rl we consider 1 ohm with two leads, Rct is usually 4ohms

Vs=10.4763*(4+2)=65.8579V

Relay will be set 0.1In or maximum sensitivity

Stabilizing Resistor=Rs =(Vs/0.1)-(AC burden/0.1 sqr) AC burden setting in 7PG23 relay is given as

Vs*20mA=65.8579*20mA=1.317158VA

Rs=(65.8579/0.1)-(1.317158/0.01)=526.8632ohms

Cs must have Knee point voltage = 2*Vs=131.7158( i.e. saety actor=2)

Operating time o Relay= 45ms at 3*Vs

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Distance Relay interview

Questions?

Engr. Qazi Arsalan Hamid

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1. Te high-voltage power transmission line protection. ypically which type o relay

protection used?

Answer 1: Voltage Relay

Answer 2: Overcurrent Relay Answer 3: Diﬀerential Relay Answer 4: Distance Relay

Answer is 4; Distance relay is continuously

measuri-Distance relay is

continuously measuring the impedance o line -ng. the impedance o line

by taking current and

voltage line in the account. As Warrington stated in

his book “Protection relays Teir Teory and Practical”

i we use the diﬀerential relay or Voltage relay on transmission line it is principally

uneconomical. Distance relay works on very simple law, that at any point in line when ault occurs

the Voltage drop at ault will be V=IZ,it Follows that Voltage to current ratio will be Impedance,

When ault occurs inside the designated relay

ransmission line the V/I<Z, and Designated Relay operates but i ault occurs outside the Designated

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Relay operates but i the ault occurs outside the Designated Relay ransmission line the V/I>Z and Designated relay will not Operate.

2. Input signals are ed to the distance relay (Distance Relay) rom any o the ollowing devices.

Answer 1: C Answer 2: V

Answer 3: Instrument Answer 4: C and V.

Answer is 4; as we stated in Distance relay

description given above, Distance relay will measure the Voltage to current ratio, so We must give Voltage via V and Current via C in Distance Relays.

3. Analysis o the perormance o the

distance relay is generally used to analyze the diagram (Diagram) ormat.

Answer 1: R-X Diagram. Answer 2: V-I Diagram. Answer 3: P.F. Diagram Answer 4: I- Diagram

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Answer is 1; Distance relay is dealing with

Impedance, impedance is the vector sum o Resistance and Reactance o Line. R-X Diagram is the good tool or setting Fault Zone Limits, in any distance relay, three

actors are important Current, Voltage and the Phase angle between Current and Voltage.

From Voltage and current we can race Impedance, angle between voltage and angle is, or

plotting it on R-X diagram, remember R= Z cos(angle) , X=Z sin(angle) .

4. Setting the Ground Fault Distance Relay or protection when used in Single Line to Ground Fault

(SLG), we have to take into account include any parameters.

Answer 1: Power Factor

Answer 2: Compensation Factor Answer 3: Full Load Current.

Answer 4: Frequency Factor

Answer is 2; For Ground, Fault Distance relays, the aulty phase Voltage and compensated aulted

current must be used i.e

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here m is the constant , I0 is Zero sequence Current

5. Set a distance relay Step Distance

Protection Relay Zone 1, we will have to adjust working time as any.

Answer one: a 0.3-second delay. Answer two: a 0.5-second delay. Answer 3: a 1.0-second delay.

Answer 4: Adjust to work immediately. (Instantaneous)

Answer is 4.

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6. Setting a distance relay Step, Distance Protection Relay Zone 1 should be set to prevent transmission

distance estimation.

Answer 1: 40-50% o the length o the transmission line that needs protection.

Answer 4: 120% o the length o the transmission line that needs protection.

Answer is 3; Alstom book “Network Protection and automation guide “stated that 85% o

ransmission line must be set to protect in Zone 1, we kept our distance relay under reach in 1st

Zone to kept Saety margin, C Errors must be kept in View.

7. Te relay suitable or protection o long power transmission lines is

Answer 1: Te Impedance Relay.

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Answer 2: Lenticular Relay.

Answer 3: Te Quadrilateral Relay Answer 4: Te Mho Relay.

Answer is 4; the long transmission lines are reactive in nature , that is why we can use mho relay in

ransmission relay , but i arcing ault occurs at transmission line then we can implement

Quadrilateral Relay on transmission line

8. Review Below Mention Distance relay

(Distance Relays) o any type. Which type's property eatures a direction on its own.

Answer 1: Mho Relay

Answer 2: Impedance Relay Answer 3: Reactance Relay Answer 4: 1 and 2 are correct.

Answer is 4; MHO relay is Directional in nature

9. Reactance relay (Reactance Relay) is the distance relay to work on.

Answer 1: Relay or the impedance box below the set

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value.

Answer 2: Relay or the impedance room above a preset value.

Answer 3: Relay sees an instance under the tree conﬁguration.

Answer 4: Relay sees an instance higher than the pre-set value.

Answer is 2:Relay or the impedance room above a preset value.

10. Te high-voltage power lines with

impedance per phase is 1 + j10 ohm Max / Phase Determine the size and angle o impedance respectively are.

Answer 1: 10.00 ohm, 90-degree phase angle/phase. Answer 2: 10.05 ohms, 84.29 ° phase angle/phase. Answer 3: 1.00 ohm, 10-degree phase angle/phase. Answer 4: 10.00 ohm, 10-degree phase angle/phase.

Answer is 2; Z per phase= Sqrt((Sqr o 1)+(Sqr o 10))=10.05 ohm, and Phase angle per phase is

atan(10/1)= 84.29 ° phase angle

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Momtaz Alsolh

Writer, Philanthropist and

Consultant

Saudi Arabian

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O

ver the past year, I have been sharing with everyone my memoir called “Bread without Butter.” My memoir is mainly about my experiences in the construction

industry in the GCC region and this afer having

worked or the Private sector. I have done my best to highlight crucial matters that are aﬀecting employees and laborers and I have written about what should be the rights o GCC national employees, expatriate employees & oreign laborers and I have done my best to dissect sections o the Labor Law in the GCC region as well so that there is more awareness. I have also oﬀered corrective actions on all the matters that required improvement or corrections and this to any

employer or to any party that cared to read what I wrote. I have also shared my memoir with several inﬂuential

individuals and I are hoping that positive changes shall see the light very soon.

Other than the above, I have also shared several articles to promote peace in the Arab world. I am praying every single day or all the wars all around the world to end on urgent basis. I am one who believes that peace on earth is achievable shall we all believe that we are one big

amily.

o date, I have only shared 50 % o what I need to share. Tere are still several crucial matters that I need to

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Initially, I thought that it would be best to remain silent. Ten I thought again and again. Ten I realized that i I kept silent the GCC region would remain in the dark and that it was wrong not to voice out.

In the coming articles, I shall be dissecting construction contracts in a way that was never done beore. I shall

be revealing the darkest secrets o the construction

industry.I shall be dissecting the complete construction contract awarding process, the construction contract preparation, the Bill o Quantities,the Contract

Speciﬁcations and much more. I shall be writing mainly

I shall be revealing the

darkest secrets o the

construction industry

about the misuse and abuse o the FIDIC orm o construction contracts.

FIDIC stands or the International Federati--on o Consulting Engineers.

Te biggest mistake in the GCC construction industry was to depend on a oreign orm o contract that only a ew knew the secrets.

Te FIDIC orm o contracts have done the GCC region very wrong due to the individuals that knew the secrets

and that took advantage o those that didn’t know the

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the secrets. What a great world that we live in!

Te strict majority o those that knew the secrets o the FIDIC orm o contracts and that have abused and misused such contracts are not GCC nationals. Our dependence on expatriates to handle construction contracts and to ﬁnalize mega deals was our biggest mistake which has led to several raudulent practices and several malpractices as well.

Te reality is that there is more money that can be saved out o managing correctly the construction contract

than the actual savings that can be done through the procurement process or through the savings on proper project management.

Once again, I shall be discussing the absence o honest and appropriate internal and external auditing in the

construction industry. I believe that auditors themselves need to be audited and they also need to be certiﬁed

by local GCC governments as many are not qualiﬁed enough to conduct their jobs and this in an ethical,

proessional or correct manner. Mainly, auditors lack the investigative sense.

Auditing is a skill that is innate and it is an art that not many possess.

Ten comes the quality management system certiying bodies who certiy construction companies blindly.

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I shall be explaining everything in detail.

I shall also be discussing the importance o having a localized orm o the construction contract that I have called “Te Uniﬁed GCC Form o Construction Contract.”

“Te Uniﬁed GCC Form o Construction Contract” shall be what the GCC region actually requires to be

protected against those that have outsmarted the FIDIC orm o contracts and that have done the FIDIC orm o contracts very wrong.

I personally believe that FIDIC is not suitable any longer or the GCC region and I shall, later on, explain why.

I am one who shall always believe in honesty and justice. I am also one who shall always believe in innovation

and continuous improvement and or these reasons, the time has come to make drastic changes. I have always believed that what is wrong will never be right.

Tat is all that I am willing to share or now.

Important hope: I am still praying to Almighty Allah (God) to see the light o the air and just 2016 Labor Law in all GCC countries.

Important reminder:

Tere is a saying that goes like this: “Forgiven is the one that has warned!”

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E-QUOES

"Quotes Wall For

Engineers"

Carpediem

Research Desk

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“But remember this,

Japanese boy... airplanes are not tools or war.

Tey are not or making money. Airplanes

are beautiul dreams. Engineers turn dreams into reality.”

Hayao Miyazaki

“Engineers like to solve problems. I there are no

problems handily available, they will create their own problems.”

Scott Adams

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“One man’s “magic” is another man’s engineering. “Supernatural” is a null word.” Robert A. Heinlein 30

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Final Semester

Engr. Qazi Arsalan Hamid

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L

ast month I was in Pakistan, I arranged sittings with diﬀerent universities students to dig out that what are they thinking about Post degree scenario or uture, Hammed rom UI told me “I am exciting about the

ascination o my education curriculum, but most o the proessor style o delivering lectures are boring and they always paint any o our requirement in terms o exams marks”. anveer rom Mehran university told, “ most o the lecturers are threatened us in the classroom while we asked questions that i you want to knew it read it by yoursel, we are bound to deliver as per curriculum”. Ms. Anum rom Mehran University inormed that afer degree program she wants to do masters and Ph.D., but the issue is that most o the scholarships are reserved or University lecturers, these lecturers take lion share rom the allotted scholarships and other deserving candidates are out o the picture due to other commitments.

Hassan rom Nust told “We are araid afer aizaz’s

suicide, 1st we have thoughts that we will be engineers we will be ﬁxed anywhere, but due to aizaz’s death now we have parallel thoughts, in our universities there is no career consultation group or advisor, senior engineers are busy in their work they are even not ready to come to our university or ready to allow us in their oﬃces or

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career advice”, usee rom Ned university told “ 1st I am planning to launch my ﬁnal year project in the market with a bank loan, but on peers pressure I am dropping this idea as no one is ready to buy my idea, everyone in my group and my internal advisor is

advising me that it is not possible” , Raheel rom Quaid e Awam told “ I am ed up with LinkedIn and Facebook job groups, most o the posted jobs are raud and

most o the overseas recruiters asked money or visa processing and job allotment”.

I talked with One university Proessor, I promised to not disclose his name in this article, he inormed” look we are tasked to deliver lecture as per the

approved curriculum, we also try to give some extra inormation but tight schedule and limited resources are not permitting us to go beyond our aligned virtual boundaries”

One oversea recruiter inormed me “look Arsalan,

most o these resh graduates are willing to pay money and they offered us first, and rom us some recruiters accepted their offers, but most o us denied these offers, because we have to deliver best human resource to our client else they will not come to us again, or us our

client is main source o business not applicant”

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Engineer Making

diﬀerence

Edvard Csanyi, he is ounder and electrical engineer at EEP. Love in electrical engineering moved and motivated him to create all-in-one handy place like

EEP and to share all his knowledge and experience, as well as to attract other electrical engineers to do the same.

He is highly specialized or design o low voltage high power busbar trunking (<6300A) in power substations, buildings and industry ascilities as well as designing o low voltage and medium voltage switchgears.

Weblink: http://electrical-engineering-portal.com/

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Book For this

month

High-Voltage Engineering by Mazen Abdel-Salam.

Preview:

"Bridges the gap between laboratory research and practical applications in

industry and power utilities-clearly organized into three distinct sections that cover basic theories and concepts, execution o principles,and innovative new techniques.

Includes new chapters detailing industrial uses and isues o hazard and saety, and review excercises to accompany each chpter."