Wednesday, November 23, 2011
Tuesday, November 22, 2011
When it comes to Electrical..
Voltage is always about insulation and Current is always about ratings...
Thursday, November 17, 2011
Which One is more dangerous: Voltage or Current?
Here is the analogy:-
" Imagine yourself fall down from a very high level of waterfall land then carried away by a very rapid water flows" aren't both situation are dangerous?
The same case as voltage and current. Voltage is dangerous when it is high coz it generates potential. In an open space you cannot go to near to a high voltage installation as you could get a flash over.
As for current even though it is low, it is still dangerous if you come in contact with the conductor coz you will become a pathway for the current to flow through to the earth.
" Imagine yourself fall down from a very high level of waterfall land then carried away by a very rapid water flows" aren't both situation are dangerous?
The same case as voltage and current. Voltage is dangerous when it is high coz it generates potential. In an open space you cannot go to near to a high voltage installation as you could get a flash over.
As for current even though it is low, it is still dangerous if you come in contact with the conductor coz you will become a pathway for the current to flow through to the earth.
Pencawang Pembahagian
Definisi:
Pencawang Pembahagian adalah penempatan dan pemasangan beberapa perkakasan atau radas elektrik seperti
1. pensuisan voltan tinggi
2. pengubah 3 fasa
3. kabel voltan tinggi
4. kabel voltan rendah dan
5. pengagihan voltan rendah, pengecas bateri dll
yang digunakan utk mengarahkan pengaliran tenaga elektrik dalam sistem kuasa dan memastikan keselamatan sistem dengan menggunakan satu skim perlindunga.
Kategori Pencawang Pembahagian:
1. Pencawang Masuk Utama: tempat dimana voltan tinggi direndahkan ke voltan pembahagian
2. Pencawang Pembahagian Utama: tempat dimanak voltan tinggi pembahagian 33kV atau 22kV diturunkan kepada rangkaian 11kV
3. Stesen Suis Utama: tempat dimana pengumpulan dan pemasangan voltan tinggi 33kV, 22kV atau 11kV sahaja dan tanpa alatubah
4. Pencawang Elektrik: tempat dimana voltan tinggi pembahagian 33kV/22kV/11kV diturunkan ke voltan yang lebih rendah iaitu 433 Volt bagi membekalkan tenaga elektrik ke pengguna.
5 jenis PE
1. Pencawang Berbangunan - biasanya di kawasan perumahan atau kilang
2. Pencawang Luar Bangunan berpagar - biasanya di kawasan kilang atau luar bandar
3. Pencawang Atas Tiang - biasanya untuk kawasan luar bandardimana beban setempat tdk terlalu tinggi
4. Pencawang Padat -
5. Pencawang Dalam Tanah
Komponen Asas Pencawang Elektrik
1. Kepungan - Bangunan, Pagar, Kiosk Tertutup Logam atau Tiang
2. Alat Pensuisan Voltan Tinggi & Voltan rendah - Pemutus Litar, RMU, Isolator, LV Dist Board, Fuse
3. ALatubah - 3 Fasa
4. Kabel - Voltan tinggi & Rendah
5. Sistem Perlindunga - Relay & Fuse
6. Sistem Pembumian - Letrod bumi, Penangkap Kilat
7. ALat Pemadam Api - CO2 dry powder
8. Cap Bank - memperbaiki faktor kuasa
9. DC system - 110V for 33kV and 30V for 11kV
10. Arahan pertolongan cemas
11. Tikar Getah - for indoor substation
Peralatan Utama Pencawang Elektrik
1. Alatsuis - circuit breaker or RMU
2. Alatubah - to step down voltage
3. LV Dist Board - mempunyai busbar, link, fius dan juga alat pengukuran. Dua kategori: feeder pillar dan LV Board
Perbezaan antara Circuit breaker dan RMU adalah CB mempunyai sistem perlindungan pada outgoing feeder yang menggunakan DC. Manakala, RMU hanya pada litar Tee Off untuk alatubah sahaja yang mempunyai sistem perlindungan menggunakan fius voltan tinggi tanpa memerlukan DC.
Sistem Sokongan Pencawang Elektrik
1. Sistem Pembumian
2. Sistem Bekalan arus terus (DC)
Pencawang Pembahagian adalah penempatan dan pemasangan beberapa perkakasan atau radas elektrik seperti
1. pensuisan voltan tinggi
2. pengubah 3 fasa
3. kabel voltan tinggi
4. kabel voltan rendah dan
5. pengagihan voltan rendah, pengecas bateri dll
yang digunakan utk mengarahkan pengaliran tenaga elektrik dalam sistem kuasa dan memastikan keselamatan sistem dengan menggunakan satu skim perlindunga.
Kategori Pencawang Pembahagian:
1. Pencawang Masuk Utama: tempat dimana voltan tinggi direndahkan ke voltan pembahagian
2. Pencawang Pembahagian Utama: tempat dimanak voltan tinggi pembahagian 33kV atau 22kV diturunkan kepada rangkaian 11kV
3. Stesen Suis Utama: tempat dimana pengumpulan dan pemasangan voltan tinggi 33kV, 22kV atau 11kV sahaja dan tanpa alatubah
4. Pencawang Elektrik: tempat dimana voltan tinggi pembahagian 33kV/22kV/11kV diturunkan ke voltan yang lebih rendah iaitu 433 Volt bagi membekalkan tenaga elektrik ke pengguna.
5 jenis PE
1. Pencawang Berbangunan - biasanya di kawasan perumahan atau kilang
2. Pencawang Luar Bangunan berpagar - biasanya di kawasan kilang atau luar bandar
3. Pencawang Atas Tiang - biasanya untuk kawasan luar bandardimana beban setempat tdk terlalu tinggi
4. Pencawang Padat -
5. Pencawang Dalam Tanah
Komponen Asas Pencawang Elektrik
1. Kepungan - Bangunan, Pagar, Kiosk Tertutup Logam atau Tiang
2. Alat Pensuisan Voltan Tinggi & Voltan rendah - Pemutus Litar, RMU, Isolator, LV Dist Board, Fuse
3. ALatubah - 3 Fasa
4. Kabel - Voltan tinggi & Rendah
5. Sistem Perlindunga - Relay & Fuse
6. Sistem Pembumian - Letrod bumi, Penangkap Kilat
7. ALat Pemadam Api - CO2 dry powder
8. Cap Bank - memperbaiki faktor kuasa
9. DC system - 110V for 33kV and 30V for 11kV
10. Arahan pertolongan cemas
11. Tikar Getah - for indoor substation
Peralatan Utama Pencawang Elektrik
1. Alatsuis - circuit breaker or RMU
2. Alatubah - to step down voltage
3. LV Dist Board - mempunyai busbar, link, fius dan juga alat pengukuran. Dua kategori: feeder pillar dan LV Board
Perbezaan antara Circuit breaker dan RMU adalah CB mempunyai sistem perlindungan pada outgoing feeder yang menggunakan DC. Manakala, RMU hanya pada litar Tee Off untuk alatubah sahaja yang mempunyai sistem perlindungan menggunakan fius voltan tinggi tanpa memerlukan DC.
Sistem Sokongan Pencawang Elektrik
1. Sistem Pembumian
2. Sistem Bekalan arus terus (DC)
Sunday, October 23, 2011
Monday, September 5, 2011
Are you a Competent Person??
Are you a Competent Person?? what would you think if somebody ask you this question? what do you understand with the word competent? Yess...anything can be interpreted right.. Anyway, I'm just asking coz at the moment I'm in d midst of applying for competent engineer interview and examination. This was the question that i asked myself: Am I competent enough to go for the interview? After a few moments of thoughts I finally say Yes. haha yes I did say that.
Think about this...competent is defined as having the necessary ability, knowledge or skill to do something successfully. And you can be considered competent if have enough experience the field where you have been working on. so In short, I'm eligible to go for the competency interview, since i have years of working experience + knowledge in this field.
So friends, if you think you are competent enough already to go for the next level, never hesitate to go forward. Just ask your self a simple question and answer it honestly. you will find the answer.
till then...bla bla bla.. lol (just want to update this site since it was abandoned sometime ago.. ^^
Think about this...competent is defined as having the necessary ability, knowledge or skill to do something successfully. And you can be considered competent if have enough experience the field where you have been working on. so In short, I'm eligible to go for the competency interview, since i have years of working experience + knowledge in this field.
So friends, if you think you are competent enough already to go for the next level, never hesitate to go forward. Just ask your self a simple question and answer it honestly. you will find the answer.
till then...bla bla bla.. lol (just want to update this site since it was abandoned sometime ago.. ^^
Sunday, May 9, 2010
Sunday, April 25, 2010
Insulation Resistance Test
What is insulation resistance testing?
- Basically, you're applying a voltage (specifically a highly regulated, stabilized DC voltage) across a dielectric, measuring the amount of current flowing through that dielectric, and then calculating (using Ohm's Law) a resistance measurement.
- Let's clarify our use of the term "current." We're talking about leakage current. The resistance measurement is in megohms. You use this resistance measurement to evaluate insulation integrity.
What affects insulation resistance readings?
- Insulation resistance is temperature-sensitive. When temperature increases, insulation resistance decreases, and vice versa.
- A common rule of thumb is insulation resistance changes by a factor of two for each 10 DegrC change. So, to compare new readings with previous ones, you'll have to correct your readings to some base temperature.
- For example, suppose you measured 100 megohms with an insulation temperature of 30 DegrC. A corrected measurement at 20 DegrC would be 200 megohms (100 megohms times two).
Wednesday, April 21, 2010
Why Tangent Delta Test is important?
Electrical properties of the insulating system change due to age and continuous electrical street. The principal contributor to the unexpected breakdown of the high voltage equipment is the insulation failure.
As compared to the magnetic, conducting & insulating materials which form the basics of any electrical equipment, the insulating material is more prone to service stresses like thermal stress, electrical stress, mechanicals stress, environment stress etc.
By measuring the electrical properties such as capacitance and Tan-Delta regularly on periodical basis, it is possible to ensure the operational unexpected breakdown.
Dissipation factor (Tan-Delta) is one of the most powerful off-line nondestructive diagnostic tool to monitor the condition of solid insulation of various high voltage equipment. Capacitance and Tan-Delta values obtained on new insulation are treated as benchmark readings. Then by measuring and comparing the periodical readings of the capacitance and Tan-Delta of the insulating material with the benchmark readings, one can know the rate of deterioration of the health of the insulation.
Knowing the rate of deterioration, we can be able to Predict the future unexpected breakdown of the insulation of HV equipment. Plan the maintenance schedule. Repair the insulation before actual flashover, saving high cost of replacement of material which will reduce the inventory well as delay in procurement at the last minute.
After repair, quality of insulation can be checked before returning the equipment to service. When to check capacitance & Tan-Delta During manufacturing process preferably at each stage. In service & will be depend on rate of change of Tan-Delta Vs Voltage Vs Time (Month/Year).
Frequency of testing depends on history of past failures on same machine. Frequency of testing depends on environmental conditions. More humidity, temperature, pollution would require frequency measurement of Tan-Delta.
Wednesday, March 24, 2010
How to Calculate the Short Circuit Current rating Capacity for Cables??
Just recently i learnt something new..the basic concept of engineering..once again almost forgotten until I was asked this question..."Do you know how to calculate short circuit current rating capacity for cables?", for a moment i stop and think.. i didnt know what is the answer...
*(^-^)* - (embarrased)
From there, i didn't stop but I started checking through my text books, surf internets, discuss with my collegues who in charge with planning, protection schemes and etc..
I finally found the answer..it is just a very simple formula..
Isc = VLN/Sqr. Z^2 ; VLN = Line to Neutral Voltage
Z = Positive sequence impedance of the cable (u can get from the
technical particular of the cable)
Very simple right...wait a minute, don't be mistaken with the other formula where u need to add in the impedance of the transformerr and generators. U need this data when u want to know what would be the the short circuit current when fault occurs on any part of the system..
*(^-^)* - (embarrased)
From there, i didn't stop but I started checking through my text books, surf internets, discuss with my collegues who in charge with planning, protection schemes and etc..
I finally found the answer..it is just a very simple formula..
Isc = VLN/Sqr. Z^2 ; VLN = Line to Neutral Voltage
Z = Positive sequence impedance of the cable (u can get from the
technical particular of the cable)
Very simple right...wait a minute, don't be mistaken with the other formula where u need to add in the impedance of the transformerr and generators. U need this data when u want to know what would be the the short circuit current when fault occurs on any part of the system..
Monday, March 8, 2010
Authorised Person
Yesterday was the 1st time ever that I take charged for switching off bay in order to carry out works in the switchyard. Luckily everything went smoothly.
This time, we had requested outage for a 132/33kV transformer bay in order to replace the Neutral Earthing Resistor (NER) by the contractor. The work started at 7:00 am and completed at 4:00pm.
So as an Authorised Person in charged, I have to make sure that all safety precaution for the works are in place. So, after the switching whereby the Tx bay was off, isolated, I have to make sure that it was discharged and earthed and remain dead during the entire work. Portable Earthing were installed at both HV and LV side of the transformer.
Confirmed that the bay is safe for working, I gave safety briefing to the workers. Informed them on the coverage of area that was safe for work and are that is Live an dangerous. I also ensure that all workers were wearing Personal Protective Equipment (PPE) such as safety helmet and safet shoes.
This time, we had requested outage for a 132/33kV transformer bay in order to replace the Neutral Earthing Resistor (NER) by the contractor. The work started at 7:00 am and completed at 4:00pm.
So as an Authorised Person in charged, I have to make sure that all safety precaution for the works are in place. So, after the switching whereby the Tx bay was off, isolated, I have to make sure that it was discharged and earthed and remain dead during the entire work. Portable Earthing were installed at both HV and LV side of the transformer.
Confirmed that the bay is safe for working, I gave safety briefing to the workers. Informed them on the coverage of area that was safe for work and are that is Live an dangerous. I also ensure that all workers were wearing Personal Protective Equipment (PPE) such as safety helmet and safet shoes.
Sunday, March 7, 2010
Professional Engineer Part 3
Finally the day for the P.I had over. However, I still got few more works to do in order to be a
P.Eng. as i need to submit a clearer schematic drawing to my interviewer. This is because the drawing in my submission earlier was not clear and the fonts are small. So I have to enlarge and make another copy of drawings.
Another things, I have to put more spice into my essays..hehe so needless to say much..just re-do it. At least my interviewer is very sporting and considerate as He gives chance for me to re do and improve. So lucky me! *(^_^)* (Thanking God for that)
Now, I just need a little bit more time to complete my essays and get my mentor to sign new copy enlarged drawing....hopefully i can get it done fast..(too many works to do in the office...duiiigiiiaa I'm so overwhelmed now)
P.Eng. as i need to submit a clearer schematic drawing to my interviewer. This is because the drawing in my submission earlier was not clear and the fonts are small. So I have to enlarge and make another copy of drawings.
Another things, I have to put more spice into my essays..hehe so needless to say much..just re-do it. At least my interviewer is very sporting and considerate as He gives chance for me to re do and improve. So lucky me! *(^_^)* (Thanking God for that)
Now, I just need a little bit more time to complete my essays and get my mentor to sign new copy enlarged drawing....hopefully i can get it done fast..(too many works to do in the office...duiiigiiiaa I'm so overwhelmed now)
Tuesday, January 12, 2010
Professional Engineer Part 2
1. Training reports submitted to IEM? - Checked..
2. Going for Professional Interview - Checked.. what to prepare??
a. IEM committee will appoint a principal interviewer, and the selected Ir. will appoint second
interviewer. So in total there will be 2 interviewers.
b. There will be 2 sections of essay to answer during the interview
Section A : Question regarding all your working/training experience or general knowlegde
Section B: 2 questions of code of ethics selected from the 15 nos. questions given.
during the interview, interviewer will select 1 Q out of the 2 Qs for you to
answer..
PI has to be conducted within 3 months from the notification letter issued by IEM.
Good Luck....
2. Going for Professional Interview - Checked.. what to prepare??
a. IEM committee will appoint a principal interviewer, and the selected Ir. will appoint second
interviewer. So in total there will be 2 interviewers.
b. There will be 2 sections of essay to answer during the interview
Section A : Question regarding all your working/training experience or general knowlegde
Section B: 2 questions of code of ethics selected from the 15 nos. questions given.
during the interview, interviewer will select 1 Q out of the 2 Qs for you to
answer..
PI has to be conducted within 3 months from the notification letter issued by IEM.
Good Luck....
Wednesday, August 12, 2009
Wanna Be A Professional Engineer??
It is well known that every engineering students who will work as an engineer when they graduate has to be registered with the Borad of Engineer (BEM) before they can practise their engineering knowledge..this is the LAW in our country..
Currently the pathway to be a professional engineer is as follows:
1. Register with BEM
2. Register with IEM as Grad. Member
3. Prepare Log Book or Practical work report
4. Go for the Prof. Interview with IEM
5. Approved as IEM Corporate Member
6. Get Endorsement to BEM
7. Certified Professional Engineer and Get the Title as Ir.
phew...what a long list... ;-)
Anyway, Good luck to all future PE okay...
Currently the pathway to be a professional engineer is as follows:
1. Register with BEM
2. Register with IEM as Grad. Member
3. Prepare Log Book or Practical work report
4. Go for the Prof. Interview with IEM
5. Approved as IEM Corporate Member
6. Get Endorsement to BEM
7. Certified Professional Engineer and Get the Title as Ir.
phew...what a long list... ;-)
Anyway, Good luck to all future PE okay...
Monday, July 27, 2009
Things you should know as a maintenance engineer
Hello All...Ok here is the list that i think essential for all maintenance engineer in the power utility....
1. Must know the basic of P=IV haha V=IR and etc....wajib ni...
2. Must be able to differentiate what is Switching Single Line Diagram and Protection Single Line Diagram
3. Must know Basic of Troubleshooting...
4. Must know what is NOMENCLATURE...
5. Must be able to define Routine Maintenance, Preventive Maintenance & Corrective Maintenance
6. Must know the purpose of condition monitoring such as infrared thermography...
7. A little bit of chemist...this will be needed when you do DGA for power transformer
8. Know how many types of primary equipment in the switchyard, their functions and etc.
9. Know a bit of Protection...c'mon..u gonna be on standby..
10. know to find where is the O&M Manuals...aha..
1. Must know the basic of P=IV haha V=IR and etc....wajib ni...
2. Must be able to differentiate what is Switching Single Line Diagram and Protection Single Line Diagram
3. Must know Basic of Troubleshooting...
4. Must know what is NOMENCLATURE...
5. Must be able to define Routine Maintenance, Preventive Maintenance & Corrective Maintenance
6. Must know the purpose of condition monitoring such as infrared thermography...
7. A little bit of chemist...this will be needed when you do DGA for power transformer
8. Know how many types of primary equipment in the switchyard, their functions and etc.
9. Know a bit of Protection...c'mon..u gonna be on standby..
10. know to find where is the O&M Manuals...aha..
Subscribe to:
Posts (Atom)