73 entries.
wrote on June 16, 2020
at
9:09 PM
Hello there!
I am a manufacturing engineer at steel plant in Port Talbot (so mostly hands-on guy), Wales. I am designing (well trying!) a 3 winding step up transformer 33kV (P) /132kV (S) , 90MVA. One the 132kV(S) side, I want to create a two windings. S1 will be 99kV rated and S2 will be 33kV rated. During normal operation, the two S1& S2 will work in series. However, during the start-up, I want only 33kVv(S2) winding to work. This way i can get more current into the electric rods to melt the scrap in an electric arc furnace.
Please can anyone suggest how I can rate the windings resistance and reactance values. I would like to send you an excel document and show some calculated values. It would be kind (and great) if anyone can provide some feedback on my calculations and correct them for the three different scenarios with some comments about pros and cons.I really need to understand if the values make any sense as I have no sounding board here.
many thanks in advance!
I am a manufacturing engineer at steel plant in Port Talbot (so mostly hands-on guy), Wales. I am designing (well trying!) a 3 winding step up transformer 33kV (P) /132kV (S) , 90MVA. One the 132kV(S) side, I want to create a two windings. S1 will be 99kV rated and S2 will be 33kV rated. During normal operation, the two S1& S2 will work in series. However, during the start-up, I want only 33kVv(S2) winding to work. This way i can get more current into the electric rods to melt the scrap in an electric arc furnace.
Please can anyone suggest how I can rate the windings resistance and reactance values. I would like to send you an excel document and show some calculated values. It would be kind (and great) if anyone can provide some feedback on my calculations and correct them for the three different scenarios with some comments about pros and cons.I really need to understand if the values make any sense as I have no sounding board here.
many thanks in advance!
Admin Reply by: Ver Pangonilo
Hi,
The best way to do what you are trying to achieve is to have an autotransformer with 33kV pri / 132KV sec.
During start-up, you can connect directly to the 33KV tap of the transformer which means that your are directly across your supply line. After which, you can switch to the 132KV leg of the transformer during normal operation.
The switching scheme for this is much easier than what you are thinking of. series connected secondary winding. The footprint of the autotransformer will be smaller than a two-winding transformer. This makes your equipment much cheaper.
You need to approach a transformer manufacturing company to help you with the transformer design.
The best way to do what you are trying to achieve is to have an autotransformer with 33kV pri / 132KV sec.
During start-up, you can connect directly to the 33KV tap of the transformer which means that your are directly across your supply line. After which, you can switch to the 132KV leg of the transformer during normal operation.
The switching scheme for this is much easier than what you are thinking of. series connected secondary winding. The footprint of the autotransformer will be smaller than a two-winding transformer. This makes your equipment much cheaper.
You need to approach a transformer manufacturing company to help you with the transformer design.
wrote on February 12, 2020
at
10:01 PM
Hi Sir Ver,
my search for the "FPN or Fine Print Note" led me to your blog..
I didn't expect that the search will lead me to this collection of knowledge..
very nice blog po Sir!
my search for the "FPN or Fine Print Note" led me to your blog..
I didn't expect that the search will lead me to this collection of knowledge..
very nice blog po Sir!
Admin Reply by: Ver Pangonilo
Thank you.
wrote on November 28, 2019
at
10:32 AM
Good day Sir,
In Australia, where I can find in AS/NZS 60079 standard the requirement for hazardous area classification report to approve the drawings? We were challenged by the vendor that HAC report is not required on their drawings.
Many thanks,
Jon
In Australia, where I can find in AS/NZS 60079 standard the requirement for hazardous area classification report to approve the drawings? We were challenged by the vendor that HAC report is not required on their drawings.
Many thanks,
Jon
Admin Reply by: Ver Pangonilo
The standard AS/NZS 60079 is available for purchase at https://bit.ly/33qEDwr
wrote on October 28, 2019
at
5:07 PM
Thank you for having this kind of forum website. As one of the newest Registered Electrical Engineer, I am looking for more knowledge from anyone's experience and I think, I might found it here.
Admin Reply by: Ver Pangonilo
Thank you for the compliment
wrote on September 25, 2019
at
6:18 AM
Thanks for the information regarding access. I have another query if I may - this time asking for "server".
Admin Reply by: Ver Pangonilo
Server is localhost
wrote on September 23, 2019
at
12:31 AM
Hi Sir,
I just want to ask how to solve series open faults.
1. One conductor open fault - Boundary conditions are the same with L-L-G fault. Does it mean that the way to solve one conductor open fault is the same as L-L-G fault?
2. Double conductor open fault - Boundary conditions are the same with L-G fault. Does it mean that the way to solve two conductor open fault is the same as L-G fault?
The source of the formula & conditions which I am referring was posted on below site.
http://www.engineeringenotes.com/electrical-engineering/faults/series-faults-in-3-phase-circuit-power-system-electrical-engineering/24975#targetText=The%20faults%2C%20involve%20power%20conductor,are%20termed%20as%20shunt%20faults.&targetText=Series%20faults%20are%20characterized%20by,current%20in%20the%20faulted%20phases.
I just want to ask how to solve series open faults.
1. One conductor open fault - Boundary conditions are the same with L-L-G fault. Does it mean that the way to solve one conductor open fault is the same as L-L-G fault?
2. Double conductor open fault - Boundary conditions are the same with L-G fault. Does it mean that the way to solve two conductor open fault is the same as L-G fault?
The source of the formula & conditions which I am referring was posted on below site.
http://www.engineeringenotes.com/electrical-engineering/faults/series-faults-in-3-phase-circuit-power-system-electrical-engineering/24975#targetText=The%20faults%2C%20involve%20power%20conductor,are%20termed%20as%20shunt%20faults.&targetText=Series%20faults%20are%20characterized%20by,current%20in%20the%20faulted%20phases.
Admin Reply by: Ver Pangonilo
I have discussed open circuit faults in my article Open Circuit Faults, https://pangonilo.com/2010/01/open-circuit-faults.html
wrote on September 17, 2019
at
9:49 PM
How would you fix or sort an issue to be able to get access back.
Admin Reply by: Ver Pangonilo
Will check and get back asap. All is okay now
wrote on August 27, 2019
at
10:22 PM
Defferentiate the P.E.C to N.E.C
Admin Reply by: Ver Pangonilo
PEC is Philippine Electrical Code, applicable only in the Philippines while NEC is National Electrical Code applicable in the United States. However, PEC was based on NEC but dimensions and sizes were converted into metric.
wrote on August 14, 2019
at
9:23 PM
Hi Sir, student from IIEE TSU Student Council. Just wanna ask kung saan po sa PEC yung plus minus 5% voltage tolerance sa end ng distribution. Thanks!
Admin Reply by: Ver Pangonilo
Your question is a little bit vague but you can check these clauses
For Branch circuits, check FPN 4 under 2.10.2.1 (a)(1)
For Feeders, check FPN 2 under 2.15.1.2 (a) (3)
In design, the voltage tolerance maybe assumed to a certain value which is acceptable to the end user. This are usually stated in specifications and datasheets of electrical equipment. As far as I know (I may be wrong) but PEC does not provide anything about voltage tolerances.
For Branch circuits, check FPN 4 under 2.10.2.1 (a)(1)
For Feeders, check FPN 2 under 2.15.1.2 (a) (3)
In design, the voltage tolerance maybe assumed to a certain value which is acceptable to the end user. This are usually stated in specifications and datasheets of electrical equipment. As far as I know (I may be wrong) but PEC does not provide anything about voltage tolerances.
wrote on July 22, 2019
at
3:03 PM
Good day Sir! The water pump motor in our office needs to be rewinded due to very low insulation resistance of the windings. The three-phase motor is 230 V convertible to 460 V. The motor will be used in our new building with 400 V supply voltage. The motor was used at 230 V. Is it possible to just rewind it at 400 V even though it is designed at 460 V? If not, should we just rewind it at 230 V and buy a 400 V step-up, dry-type transfromer or rewind it to 460 V and buy a 400 V step-down transformer? What is the most cost-effective approach Sir? Thank you very much. Hoping for your response on this matter.
Admin Reply by: Ver Pangonilo
Dear Racquel,
As you have not mentioned the size of your water pump motor, rewinding a 230V to 460V will be the most cost-effective. However, ensure that you choose a COMPETENT rewinding contractor to do the job. But, as the operating voltage (400V) is lower than the rated voltage (460V), efficiency will be lower. Long term, I would suggest buying a 400V, 3 phase motor for the application.
Regards,
Ver
As you have not mentioned the size of your water pump motor, rewinding a 230V to 460V will be the most cost-effective. However, ensure that you choose a COMPETENT rewinding contractor to do the job. But, as the operating voltage (400V) is lower than the rated voltage (460V), efficiency will be lower. Long term, I would suggest buying a 400V, 3 phase motor for the application.
Regards,
Ver
wrote on June 3, 2019
at
3:39 AM
Hello Sir, I’m soon to have a home built in the Philippines. All the power outlets I have observed there are of two pin variety, however , I’m wondering how I can ensure that in fact all the power outlets have all three supply cables - Live - Neutral and an Earth connection.
Looking forward to reply.
Thank you, and regards,
Mr John Cox
Looking forward to reply.
Thank you, and regards,
Mr John Cox
Admin Reply by: Ver Pangonilo
Depending on the location of your house to be built, there power outlet configuration will vary.
In the Meralco franchise area, power will have a 115V-0-115V. In here you can use the NEMA 6-20R outlet. However, if your house is covered by an Electric Cooperative franchise, your power will be supplied at 230V-0 configuration. In this case two pole outlet may be used but you can still use a NEMA 6-20R outlet if you wish.
In the Meralco franchise area, power will have a 115V-0-115V. In here you can use the NEMA 6-20R outlet. However, if your house is covered by an Electric Cooperative franchise, your power will be supplied at 230V-0 configuration. In this case two pole outlet may be used but you can still use a NEMA 6-20R outlet if you wish.
wrote on May 29, 2019
at
5:44 PM
Good day sir, what are the possible reasons for the hard starting of the 3 phase generator?
Admin Reply by: Ver Pangonilo
You need to ask your mechanic about your generator engine.
wrote on May 27, 2019
at
10:23 AM
Good day, Engr. Ver, first of all, thank you for the information and tutorials that you have shared, it has been valuable for furthering my EE knowledge. Do you have any additional book recommendations, websites or articles that can help me deepen my understanding of general EE, and power system design and analysis? Thanks!
Admin Reply by: Ver Pangonilo
There are lots of books out there that I could not say which one is best. Just ask Mr Google.
Thanks for the compliments.
Thanks for the compliments.
wrote on May 14, 2019
at
7:44 PM
Sir, your site is very informative for practicing electrical engineers in the Philippines. Thank you for all the compilations in your site.
Just a query, Part 2 of the Philippine Electrical Code. I've checked with IIEE but it's unavailable. By any chance, do you have an e-copy? Thank you very much
Just a query, Part 2 of the Philippine Electrical Code. I've checked with IIEE but it's unavailable. By any chance, do you have an e-copy? Thank you very much
Admin Reply by: Ver Pangonilo
Thanks for the compliment.
I only have a hard copy of PEC 2.
I only have a hard copy of PEC 2.
wrote on May 10, 2019
at
9:50 PM
I am a plan checker and we have a difference of opinion in my company. My stance is the only one who is allowed to stamp and sign electrical and solar is an electrical engineer or a c-10. can you help me prove my case and help me find where to find that rule or law.
Admin Reply by: Ver Pangonilo
As you have not mentioned your project location, I will not be able to answer your query. Thank you
wrote on May 10, 2019
at
9:45 PM
I need to know who is allowed to sign electrical and solar plans
Admin Reply by: Ver Pangonilo
Only registered professional engineers with a valid license can sign and seal electrical plans.
wrote on May 3, 2019
at
11:47 PM
good day sir! may i know if a Filipino engineer, a civil engineer for example, could work as an engineer in Australia?
Admin Reply by: Ver Pangonilo
If you are a Filipino Engineer and wanted to work in Australia as an Engineer, then your best option is to consult Engineers Australia (https://www.engineersaustralia.org.au/)
wrote on April 9, 2019
at
12:30 PM
I am looking for the excel files of the following:
Creating Coordination Curves with Excel
Time-Current Curves with Excel II
Time-Current Curves with Excel III
Time-Current Curves with Excel IV
Creating Coordination Curves with Excel
Time-Current Curves with Excel II
Time-Current Curves with Excel III
Time-Current Curves with Excel IV
Admin Reply by: Ver Pangonilo
The tutorial is very comprehensive that you will be able to recreate the excel files itself. A sample application can be downloaded in the download section of my blog.
wrote on March 25, 2019
at
11:45 PM
Im a fifth year electrical engineering student from Bulacan, State, University and one of our professor wants us to find a plan, either a commercial or industrial plan with a load rating of 5MVA. Please help me to find a plan. Your response will be greatly appreciated.
Admin Reply by: Ver Pangonilo
Sorry for the late reply. I do not have any industrial plant plans. Thank you
wrote on March 9, 2019
at
7:55 PM
Sir, good day po!
Ask ko lang po, anong provision po sa PEC yung nagsstate ng standards for medium voltage electrical distribution? For example, yung size po ng poles na gagamitin saka po mga wire sizes and other things na need po iconsider para po sa design? marami pong salamat and more power po!
Ask ko lang po, anong provision po sa PEC yung nagsstate ng standards for medium voltage electrical distribution? For example, yung size po ng poles na gagamitin saka po mga wire sizes and other things na need po iconsider para po sa design? marami pong salamat and more power po!
Admin Reply by: Ver Pangonilo
Look at PEC Part II. You may find information in there.
wrote on February 7, 2019
at
7:17 PM
We have some 6.6kv cells which have been dismantled recently from a substation in which the European standard is used i.e.(6.6kv, 50Hz), now we are planning to install them in different plant where the American standard is used (4.16kv, 60Hz), please advice regarding the possibility of this installation.
wrote on January 15, 2019
at
11:43 PM
What is the philippine electrical code to data connection? Thank you
Admin Reply by: Ver Pangonilo
If I understand your question right, you might need to check these clauses
ARTICLE 6.45 — INFORMATION TECHNOLOGY EQUIPMENT
ARTICLE 8.30 — NETWORK-POWERED BROADBAND COMMUNICATIONS SYSTEMS
ARTICLE 6.45 — INFORMATION TECHNOLOGY EQUIPMENT
ARTICLE 8.30 — NETWORK-POWERED BROADBAND COMMUNICATIONS SYSTEMS
wrote on October 28, 2018
at
2:14 PM
Could you assist me in determining if my PV solar panel system has a safety issue involving a potential arc flash problem. I have investigated several papers on this subject and realize this is a complex voltage/current with complicated calculations beyond my complete understanding. My solar panel system design consist of two PV solar panels generating about 75VDC and 5.0ADC total directly connecting to an electric water heaters' 16ohm heating element through a 40 foot 16AWG cable. Again, my concern is do I have a safety issue here?
Any help via referals, informative articles, or experimental testing performed at these low DC voltages and low DC currents would be helpful.
If I get lucky with a response from you I am more than happy to discuss my somewhat original clever design to use existing setup involving minimum cost.
Thank you
David Lopez
[email protected]
808-868-3128
Any help via referals, informative articles, or experimental testing performed at these low DC voltages and low DC currents would be helpful.
If I get lucky with a response from you I am more than happy to discuss my somewhat original clever design to use existing setup involving minimum cost.
Thank you
David Lopez
[email protected]
808-868-3128
Admin Reply by: Ver Pangonilo
Your electric heater will draw a current from your solar panel at its peak of about 4.6A depending on the time of the day. Regarding your concern about possible arc-flash, a fault occurring at the terminal of your water heater will draw about 375A ideally. As you have not provided the technical specification of your panel, and with the minimal data you provided, I can assume that your solar panel will not be able to generate this amount of fault current. The incident energy will not be sufficient to produce an arc-flash.
IEEE 1584 can guide you on calculating arc-flash.
IEEE 1584 can guide you on calculating arc-flash.
wrote on September 11, 2018
at
3:23 PM
Sir Ver,
Thank you for your valuable information and tutorials
Thank you for your valuable information and tutorials
Admin Reply by: Ver Pangonilo
My pleasure. Thank you
wrote on August 1, 2018
at
7:42 PM
hi engr ver,
where can I find IEC 6909 standard for short circuit calculations? I hope I can get a copy. thanks sir
where can I find IEC 6909 standard for short circuit calculations? I hope I can get a copy. thanks sir
Admin Reply by: Ver Pangonilo
The correct number for the standard is IEC 60909. Check IEC web store at https://webstore.iec.ch/publication/24100
wrote on August 1, 2018
at
7:31 PM
hi sir,
can I ask if there is a short circuit calculations under no load condition. thank you sir
can I ask if there is a short circuit calculations under no load condition. thank you sir
Admin Reply by: Ver Pangonilo
Yes there is a no load short circuit calculation. There will be no load contribution to the total short circuit current.
wrote on July 31, 2018
at
3:54 PM
Hye Ver.
Can I habve your email?
Need to attach some examples of source impedance calculation.
Can I habve your email?
Need to attach some examples of source impedance calculation.
Admin Reply by: Ver Pangonilo
Please send queries to this email: admin@pangonilo.com
wrote on June 18, 2018
at
1:29 PM
Dear Engrs,
What is the standard height of switches?
thank you and regards,
What is the standard height of switches?
thank you and regards,
Admin Reply by: Ver Pangonilo
The PEC does not have a provision on the mounting height of switches. This means that it will be all up to the end-user whatever is convenient.
wrote on June 13, 2018
at
10:13 PM
Tanung lang po... pwede po mag tap ng cable sa common busbar ng mvsg (I mean dun talaga mag tap to get power). Sa pagkakaalam ko kasi medyo delikado kasi yun, unang una kaya nga naka enclosed ang busbar compartment is for safety..
Admin Reply by: Ver Pangonilo
It is possible to connect a new feeder on the busbar on the condition that you need to:
Check the fault level on the busbar to ensure that you connect the right protective device and cable
Install a protective device just downstream the busbar
Ensure that you are competent to do the job else ask a competent Electrical practitioner to do the job for you.
Check the fault level on the busbar to ensure that you connect the right protective device and cable
Install a protective device just downstream the busbar
Ensure that you are competent to do the job else ask a competent Electrical practitioner to do the job for you.
wrote on April 5, 2018
at
9:13 AM
Refer to https://pangonilo.com/tutorials/mva-method/short-circuit-study
SC MVA = KV2 / Z
From IEE regulation Table 4D2B (column 3, 4)
Cable 120mm2:
(mV/A/m)r = 0.33mOhm
(mV/A/m)x = 0.135mOhm
Assume:
R = (0.33mOhm x 30m) / (Sqrt 3 x 1000 ) = 0.0057 ohm
X = (0.135mOhm x 30m) / (Sqrt 3 x 1000 ) = 0.0023 ohm
Z= Sqrt (R2 + X2)
SC MVA = KV2 / Z = (0.4 x 0.4) / 0.00614 = 26
Should R and X divided by Sqrt (3) for SC MVA calculation please?
SC MVA = KV2 / Z
From IEE regulation Table 4D2B (column 3, 4)
Cable 120mm2:
(mV/A/m)r = 0.33mOhm
(mV/A/m)x = 0.135mOhm
Assume:
R = (0.33mOhm x 30m) / (Sqrt 3 x 1000 ) = 0.0057 ohm
X = (0.135mOhm x 30m) / (Sqrt 3 x 1000 ) = 0.0023 ohm
Z= Sqrt (R2 + X2)
SC MVA = KV2 / Z = (0.4 x 0.4) / 0.00614 = 26
Should R and X divided by Sqrt (3) for SC MVA calculation please?
Admin Reply by: Ver Pangonilo
Ensure that you are dealing with the correct voltage. Phase voltage is required to solve for the phase cable KVA. For three (3) phase, there are 3 cables so you need to multiply the KVa by 3 to get the total cable KVA.
For single phase, it will be a different calculation.
For single phase, it will be a different calculation.
wrote on March 16, 2018
at
6:45 PM
Hi Good day!
I've been programming some relays, and now i found myself in difficulties understanding my new device. By principle i have an idea how it works but by computation i have some difficulties understanding it. My problem is the Distance Relay . I might understand the principle if i have some illustrations and sample problems with computation.
Hoping for your help and thank you in advance
I've been programming some relays, and now i found myself in difficulties understanding my new device. By principle i have an idea how it works but by computation i have some difficulties understanding it. My problem is the Distance Relay . I might understand the principle if i have some illustrations and sample problems with computation.
Hoping for your help and thank you in advance
Admin Reply by: Ver Pangonilo
The best way to understand how to program your distance relay is to refer to the user's manual. To understand the basics of distance relay, you could refer to the following
Basic_Principles_of_Distance_Protection
Distance_Relays_Fundametals
Basic_Principles_of_Distance_Protection
Distance_Relays_Fundametals
wrote on March 9, 2018
at
1:32 AM
Hi Ver! I would like to verify if I have to size the 200A main switch ampere fuse rating of a transformer at 150KVA, 600V primary and 208V primary with a secondary load of 59kW. Do I have to size the fuse base on the transformer primary overload capacity or the feeder load of 59kW? Thanks.
Admin Reply by: Ver Pangonilo
As per provision of the PEC. This is also similar to NEC provision (450.4 Autotransformers 600 Volts, Nominal, or Less).
4.50.1.4 Autotransformers 600 Volts, Nominal, or Less.
(a) Overcurrent Protection. Each autotransformer 600 volts,
nominal, or less shall be protected by an individual overcurrent device
installed in series with each ungrounded input conductor. Such
overcurrent device shall be rated or set at not more than 125 percent of
the rated full-load input current of the autotransformer. Where this
calculation does not correspond to a standard rating of a fuse or
nonadjustable circuit breaker and the rated input current is 9 amperes
or more, the next higher standard rating shall be permitted.
The load need to be protected separately.
4.50.1.4 Autotransformers 600 Volts, Nominal, or Less.
(a) Overcurrent Protection. Each autotransformer 600 volts,
nominal, or less shall be protected by an individual overcurrent device
installed in series with each ungrounded input conductor. Such
overcurrent device shall be rated or set at not more than 125 percent of
the rated full-load input current of the autotransformer. Where this
calculation does not correspond to a standard rating of a fuse or
nonadjustable circuit breaker and the rated input current is 9 amperes
or more, the next higher standard rating shall be permitted.
The load need to be protected separately.
wrote on March 1, 2018
at
5:51 PM
Hi may question lang po. Anu difference ng. 400v/230v system and 460v/230v syatem
Admin Reply by: Ver Pangonilo
A 400/230V system is 3 phase. This is an IEC standard voltage while a 460/230V system is single phase. This is a NEC & PEC standard voltage
wrote on February 20, 2018
at
11:06 PM
good day po,
Engr. Ver may training pa kayo sa scada? email me po kung meron pa thanks. [email protected]
Engr. Ver may training pa kayo sa scada? email me po kung meron pa thanks. [email protected]
Admin Reply by: Ver Pangonilo
I am sorry to say, pero wala. Thanks for the enquiry
wrote on February 15, 2018
at
2:58 AM
Engr. Ver good morning po. Tanong ko lng po, ilan po ang minimum allowable distance ng poste ng meralco sa property line ay any part ng bahay ko. Salamat po.
Chito Serrano
Chito Serrano
Admin Reply by: Ver Pangonilo
Chito, kung ang pagbabasehan ay ang PEC, sa aking kaalaman ay walang nakasaad na minimum allowable distance from the property line. Pero meron itong provision on horizontal clearances of wires and cables for other structures is 1.5m (ref. PEC 2 - 2008 Clause 3.4.5.2(a)(1)). Kaya nasa sa iyo na yun kung papayag ka na magtayo ang Meralco ng poste sa property mo.
wrote on December 20, 2017
at
1:16 PM
Where to find a book?
Philippine Electrical Codes Volume 1
Thanks,
Philippine Electrical Codes Volume 1
Thanks,
Admin Reply by: Ver Pangonilo
You can buy it from IIEE (http://iiee.org.ph)
wrote on November 23, 2017
at
6:50 PM
tanung lang po
1.0 anu po ang maximum allowable na ampacity sa switchgear (low voltage).
2.0 maximum acb rate is 6300A for low voltage application, anupong susunod na device lets say for 10000A protection, are there any.
maraming salamat po
1.0 anu po ang maximum allowable na ampacity sa switchgear (low voltage).
2.0 maximum acb rate is 6300A for low voltage application, anupong susunod na device lets say for 10000A protection, are there any.
maraming salamat po
Admin Reply by: Ver Pangonilo
It is best to consult Standards (IEEE, IEC, etc) for your question. In my designs, I used a maximum of 3200A ACB rating. Larger than that, there will be lots of issues concerning busbar sizes, temperature rise, etc.
wrote on October 30, 2017
at
10:33 PM
Good day Sir,
I have a problem with VSD failures at one of my sites (a shopping centre). The system consists of an 11kV incomer and many 11kV / 400V distribution transformers.
Power readings indicate an imbalance of voltages on the 11kV incomer terminals.
Where should I start for diagnoses?
I have a problem with VSD failures at one of my sites (a shopping centre). The system consists of an 11kV incomer and many 11kV / 400V distribution transformers.
Power readings indicate an imbalance of voltages on the 11kV incomer terminals.
Where should I start for diagnoses?
Admin Reply by: Ver Pangonilo
The very first thing that you should do is to inform your power provider of the 11KV imbalance. I believe that the culprit is on their side. To protect your VSDs, you should install an undervoltage / single phasing protection relay on the VSD feeder breaker. This protection relay will trip if a voltage imbalance occurs protecting your VSD.
wrote on October 26, 2017
at
2:50 PM
good day sir,
ask ko lang po if pwede po bang pagsamahin ang set of wires from load and line side sa iisang conduit na RSC?
salamat po
ask ko lang po if pwede po bang pagsamahin ang set of wires from load and line side sa iisang conduit na RSC?
salamat po
Admin Reply by: Ver Pangonilo
Using good engineering practice, you should not combine line side conductors and load side conductors in a single conduit.
wrote on October 19, 2017
at
1:58 PM
Good day Engr. Ver!
just passed by to say thank you..i found your site few years ago and your site really help a lot..
God bless..
just passed by to say thank you..i found your site few years ago and your site really help a lot..
God bless..
Admin Reply by: Ver Pangonilo
It's good to know you found my site helpful. Thanks for dropping by.
wrote on August 31, 2017
at
6:05 AM
I am having trouble correlating motor class insulation and its relation to B rise and F rise. For example, can you have a 65 degree ambient with Class F insulation and meet B rise, why or why not?
Admin Reply by: Ver Pangonilo
In IEC 60034-1:2004, Table 10, the maximum ambient temperature for Class B & F is 40 deg.C. The temperature rise are 130degC (Class B) & 155degC (class F). This means that the 65degC is unacceptable based on this IEC std.
wrote on August 30, 2017
at
4:09 PM
Sir Ver
Good day, im working in hospital facility, voltages in our distribution line are L1N=115v, L2N=120v, and L3N=220v, but the line to line voltage is 230v, QUESTION-what do you think is the problem. any suggestion or recommendation please. thanks
Good day, im working in hospital facility, voltages in our distribution line are L1N=115v, L2N=120v, and L3N=220v, but the line to line voltage is 230v, QUESTION-what do you think is the problem. any suggestion or recommendation please. thanks
Admin Reply by: Ver Pangonilo
I reckon that your system is Wye ungrounded with unbalance load. Check the current of each line to verify the load of each line. To solve this problem, ensure that you have asolidly grounded neutral.
wrote on July 26, 2017
at
1:28 AM
Hi Ver,
The book you have titled "Introduction to Power System Protection" is not the "Practical Power Systems Protection".
I suspect its from people from Schweitzer Engineering Laboratory (SEL) but I simply can't find it.
If you have any ideas please let me know.
Thanks and regards
Alex
The book you have titled "Introduction to Power System Protection" is not the "Practical Power Systems Protection".
I suspect its from people from Schweitzer Engineering Laboratory (SEL) but I simply can't find it.
If you have any ideas please let me know.
Thanks and regards
Alex
Admin Reply by: Ver Pangonilo
In my recollection, I believe that this book was given to us as a reference in one of the training I attended but I could not remember which one.
wrote on July 13, 2017
at
12:28 AM
Greetings Ver!
It’s my pleasure to have your contact.
I have query regarding the time-curve characteristics of the circuit breakers.
I prepared a circuit breaker coordination considering LSIG trip unit protection from downstream to upstream.
How to prepare time current curve in excel format? Is there available software for this particular requirement? Please advise.
It’s my pleasure to have your contact.
I have query regarding the time-curve characteristics of the circuit breakers.
I prepared a circuit breaker coordination considering LSIG trip unit protection from downstream to upstream.
How to prepare time current curve in excel format? Is there available software for this particular requirement? Please advise.
Admin Reply by: Ver Pangonilo
Search my site and eeame.com, you will see tutorials on how to do time current curve in excel.
wrote on May 26, 2017
at
10:29 PM
Hi Ver,
The book titled "Introduction to Power System Protection" is of interest to me and I would like to purchase it but I believe that is NOT its title.
Do you by any chance know its official title?
Thanks and regards
Alex
The book titled "Introduction to Power System Protection" is of interest to me and I would like to purchase it but I believe that is NOT its title.
Do you by any chance know its official title?
Thanks and regards
Alex
Admin Reply by: Ver Pangonilo
Try this book
Practical Power Systems Protection
Author: Les Hewitson
Practical Power Systems Protection
Author: Les Hewitson
wrote on May 19, 2017
at
2:27 AM
Sir, I am sorry for not giving all detail about the design of transformer. The detail of transformer are as:
A 2 winding 3 phase transformer of 33kV/440V, 2MVA has short circuit voltage is 6.5%.I have to put the right value of short circuit power in software so that transformer can operate with minimum loss.
I have applied common approach but not getting right value. Please let me know some approach.
A 2 winding 3 phase transformer of 33kV/440V, 2MVA has short circuit voltage is 6.5%.I have to put the right value of short circuit power in software so that transformer can operate with minimum loss.
I have applied common approach but not getting right value. Please let me know some approach.
Admin Reply by: Ver Pangonilo
Are you trying to design a transformer, want to create a transformer specification or doing a fault analysis using the transformer you mentioned? What are you trying to achieve?
wrote on May 18, 2017
at
4:26 AM
I have to know about design of two winding transformer.
SC Voltage
Isc
%imp
SC Voltage
Isc
%imp
Admin Reply by: Ver Pangonilo
With such a little detail, I am sorry but I could not help you.
wrote on May 10, 2017
at
10:36 AM
Sir,
My questions is, if your building has a large load and you are advised by the power provided to have a separate power supply. Who's responsible in providing transformer and KWH meter. Is it the customer or the power provider. Thank you.
My questions is, if your building has a large load and you are advised by the power provided to have a separate power supply. Who's responsible in providing transformer and KWH meter. Is it the customer or the power provider. Thank you.
wrote on May 7, 2017
at
2:27 PM
Hi Sir,
Thanks for the info, but how about cells C10 to C17? Looks like interpolation to me, since values were taken using long time pick-up and instantaneous pick-up, but I think I am missing something. Sorry to bother you, I really wanted to learn this excel stuff. This will be very useful for my PEE TER without using ETAP.
Regards
Thanks for the info, but how about cells C10 to C17? Looks like interpolation to me, since values were taken using long time pick-up and instantaneous pick-up, but I think I am missing something. Sorry to bother you, I really wanted to learn this excel stuff. This will be very useful for my PEE TER without using ETAP.
Regards
Admin Reply by: Ver Pangonilo
You are exactly right. Having known the two extreme points, the middle points are interpolated between them using the values from column A. Again the only reason for this is to have a smooth curve when plotted.
wrote on May 4, 2017
at
6:26 PM
Hi Sir,
It is the one that I downloaded in your website sir.
Here's the path:
https://pangonilo.com/tutorials/time-current-curves/time-current-curve-part-2-discrimination
Regards
It is the one that I downloaded in your website sir.
Here's the path:
https://pangonilo.com/tutorials/time-current-curves/time-current-curve-part-2-discrimination
Regards
Admin Reply by: Ver Pangonilo
The values on Sheet 3 Cells A9 to A18 are arbitrarily selected to provide a smooth curve when plotted. You can select any values you want. All other entries are calculated.
wrote on May 4, 2017
at
12:47 AM
Sir,
I just want to ask something in the attached excel file for Time-current curve, Sheet3, Cells C10 to C17. Are these values interpolated? I also want to know how did you arrive for the values in cells A9 to A18 Sheet3.
Thanks!
I just want to ask something in the attached excel file for Time-current curve, Sheet3, Cells C10 to C17. Are these values interpolated? I also want to know how did you arrive for the values in cells A9 to A18 Sheet3.
Thanks!
Admin Reply by: Ver Pangonilo
Can you provide the link to the article you are referring in your query?
wrote on March 14, 2017
at
12:46 AM
Hello, sir!
I don't know how to modelling autotransformer in ETAP. It's possible to modelling autotransformer?
Thank you!
I don't know how to modelling autotransformer in ETAP. It's possible to modelling autotransformer?
Thank you!
Admin Reply by: Ver Pangonilo
ETAP does not explicitly model auto-transformers.
wrote on March 7, 2017
at
11:02 AM
I'm performing a coordination study on a distribution at my school. I'm not sure how to estimate or calculate the MVAsc or X/R ration of our utility. Please help if possible. Thank you.
Admin Reply by: Ver Pangonilo
The best method is to ask your utility about these parameters.
wrote on January 2, 2017
at
12:04 AM
hi, my sir
iam from iraq electricls eng
i cant understanding the time and current
curve tripping i need pdf examples description prosiduer for the curve if you could help mi
i will be very glad from you and thank to you
iam from iraq electricls eng
i cant understanding the time and current
curve tripping i need pdf examples description prosiduer for the curve if you could help mi
i will be very glad from you and thank to you
wrote on December 17, 2016
at
11:49 AM
It's been a long time sir. Gusto ko lang po malaman kung kamusta na kayo? I hope you remember me. It's about 22 years. Sana po wag niyo naman po baliwalain itong message ko sa inyo. Bilang anak ang tanging gusto ko lang naman ay makilala yung tunay kong ama. Napakaimportanteng tao niyo po sakin. Ikaw yung inspirasyon ko sa mga pag aaral ko, na sana isang araw kapag lumaki na ako't nagkatrabaho , hahanapin ko kayo. Sana po mabasa niyo po itong message ko. I am now a 3rd year college student taking up Bachelors Degree in Computer Network Administration. Hindi lang naman po ako simpleng tao eh. I was part of your past sir. I hope kialla niyo yung mama ko, Jacqueline Simon . She said that I can find you in the internet and this is it. I've finally found you. The first time I saw your picture talagang naramdaman ko na po. Luksong dugo kumbaga. Halos kamukang kamuka ko po kayo. Im happy to see you in the picture but yet I want to talk to you personally. Im now 22 years old. I think my age is enough to know this matter. Alam niyo, bilang anak na gustong gusto ko kayong makilala ng lubusan. Lalo na hindi ko kayo nakita man lang sa paglaki ko. I hope you will see this message. This is the only way to contact you personally. This is my email if ever you want to contact me, [email protected] .Mag iingat po kayo lagi. Thank you.
wrote on December 10, 2016
at
12:06 PM
gud am sir ver
system voltage of utility is 13200V (L-L) primary, 400V(L-L)secondary, so may question is:
where i point my tap changer to come up to 400V system secondary?
can u give me sample how to bank 250kVA XF to attain my secondary voltage.
thank u
system voltage of utility is 13200V (L-L) primary, 400V(L-L)secondary, so may question is:
where i point my tap changer to come up to 400V system secondary?
can u give me sample how to bank 250kVA XF to attain my secondary voltage.
thank u
wrote on December 10, 2016
at
11:57 AM
What is the relation of transformer percent impedance to its reactive power capability?
wrote on December 6, 2016
at
9:03 PM
good day,,,i want to ask that,when we need to put a transformer a building?how much the load limit that we need to put a transformer?
wrote on October 30, 2016
at
7:07 PM
where do i ind the regulations appertaining to solar and the grid as far as connection and fitting
Admin Reply by: Ver Pangonilo
It all depends on the location.
Across Europe, solar panels have to be certified to IEC safety standard IEC 61730 and performance standards IEC 61215 or IEC 61646.
Solar grid-tie inverters have to conform to IEC 62109.
In Germany, grid-tie inverters must have a VDE126 certification,
In the United Kingdom, grid tie inverters that produce fewer than 16 amps of peak power must have G83/1 certification, and larger inverters require the much more complicated G59/1 certification.
In the United States, solar panels, solar cables and inverters have to have UL certification. Solar panels must conform to the UL 1703 standard. Grid-tie inverters must conform to UL 1741 and solar cabling must conform to UL 4703 or UL 854 (USE-2). If you are using batteries in your design, the batteries must conform to either UL 1989, UL 2054, UL-SU 2580 or UL-SU 1973.
In Canada, solar panels must conform to safety standard ULC/ORD-C1703-1 and design standards CAN/CSA C61215-08 or CAN/CSA C61646-2, whilst gridtie inverters must conform to CSA C22.2 No. 107.1. Batteries must conform to CAN/CSA F382-M89 (R2004).
In Australia, solar panels must conform to AS/NZS5033, whilst grid-tie inverters must conform to AS4777. If you are planning a stand-alone system in a building, your system must also conform to AS4509. If you are planning a mobile system, for instance in a caravan or recreational vehicle, your system must conform to AS3001.
Across Europe, solar panels have to be certified to IEC safety standard IEC 61730 and performance standards IEC 61215 or IEC 61646.
Solar grid-tie inverters have to conform to IEC 62109.
In Germany, grid-tie inverters must have a VDE126 certification,
In the United Kingdom, grid tie inverters that produce fewer than 16 amps of peak power must have G83/1 certification, and larger inverters require the much more complicated G59/1 certification.
In the United States, solar panels, solar cables and inverters have to have UL certification. Solar panels must conform to the UL 1703 standard. Grid-tie inverters must conform to UL 1741 and solar cabling must conform to UL 4703 or UL 854 (USE-2). If you are using batteries in your design, the batteries must conform to either UL 1989, UL 2054, UL-SU 2580 or UL-SU 1973.
In Canada, solar panels must conform to safety standard ULC/ORD-C1703-1 and design standards CAN/CSA C61215-08 or CAN/CSA C61646-2, whilst gridtie inverters must conform to CSA C22.2 No. 107.1. Batteries must conform to CAN/CSA F382-M89 (R2004).
In Australia, solar panels must conform to AS/NZS5033, whilst grid-tie inverters must conform to AS4777. If you are planning a stand-alone system in a building, your system must also conform to AS4509. If you are planning a mobile system, for instance in a caravan or recreational vehicle, your system must conform to AS3001.
wrote on October 29, 2016
at
12:51 PM
https://pangonilo.com/earth-fault-loop-impedance-calculation/2
In the link above page 2, earth fault loop. at the bottom you mention is 81 metres. Zs / Z. But Z already have 25 metres. I think you are saying 81 times Z? which is 81 * 25 meters for maximum length?
In the link above page 2, earth fault loop. at the bottom you mention is 81 metres. Zs / Z. But Z already have 25 metres. I think you are saying 81 times Z? which is 81 * 25 meters for maximum length?
Admin Reply by: Ver Pangonilo
The 81m is the maximum allowable length for a 2.5mm2 cable to ensure operation of the upstream protective device. Since 25m is shorter than 81m, the cable size is acceptable.
wrote on October 24, 2016
at
10:59 AM
Hi Sir,
For Earthing Grid installation, NFPA 780 requires minimum of 460mm burial below grade. If the top surface of the massive pile cap concrete, 1200mm thick, is 600mm below grade level, is the installation of lateral earth grid conductor directly above the pile cap concrete allowed?. What Standards can I refer to?
Regards and hope to hear from you on my query.
Armando
For Earthing Grid installation, NFPA 780 requires minimum of 460mm burial below grade. If the top surface of the massive pile cap concrete, 1200mm thick, is 600mm below grade level, is the installation of lateral earth grid conductor directly above the pile cap concrete allowed?. What Standards can I refer to?
Regards and hope to hear from you on my query.
Armando
Admin Reply by: Ver Pangonilo
It all depends on the location of your project. Local regulations / code of practices provide such information. At the end of the day, if you are not violating any statutory laws in your project locations, these details can be incorporated in your project specifications. Previous projects that I worked with was done in this manner as long as safety and physical damage to the installation/equipment are given utmost importance.
wrote on October 21, 2016
at
1:22 PM
Hi Sir,
How can I check the reliability of GFCI/ELCB with a leakage current set at 30mA without the use of the test button?
How can I check the reliability of GFCI/ELCB with a leakage current set at 30mA without the use of the test button?
Admin Reply by: Ver Pangonilo
Use a current injector for your purpose.
wrote on October 18, 2016
at
6:38 PM
hi sir ver
im your avid fan in terms of electrical world. by the way sir, until now di ko maintindihan kung paano ung bank ng transformer kapag 400V system.
im your avid fan in terms of electrical world. by the way sir, until now di ko maintindihan kung paano ung bank ng transformer kapag 400V system.
Admin Reply by: Ver Pangonilo
400V system is not different from 440V or 480V system. Connection is still the same.
wrote on October 12, 2016
at
4:21 AM
Dear Ver
i'm trying to apply MVA method to a very simple circuit located in the following url:
http://electrical-window.blogspot.ae/2014/01/voltage-drop-calculation-with-mva-method.html
can you plz check if his way is correct since he uses mtor MVA same as the MVA for short circuit which is different from using the rated MVA as you have indicated in your article. in etap i tried to follow you method but i cant get it, etap gives 94%. please help. thank you
i'm trying to apply MVA method to a very simple circuit located in the following url:
http://electrical-window.blogspot.ae/2014/01/voltage-drop-calculation-with-mva-method.html
can you plz check if his way is correct since he uses mtor MVA same as the MVA for short circuit which is different from using the rated MVA as you have indicated in your article. in etap i tried to follow you method but i cant get it, etap gives 94%. please help. thank you
Admin Reply by: Ver Pangonilo
For a motor with rating already in MVA with per unit reactance known, the calculation provided in said website is correct.
In the calculation I have provided in my example, the motors are lumped.
In the calculation I have provided in my example, the motors are lumped.
wrote on October 6, 2016
at
7:09 PM
Good morning Sir,
I want just to know, how we protect personel from indirect contact in a TNS system if the main circuit breaker in a distribution panel is a 03 pole circuit breaker?
I want just to know, how we protect personel from indirect contact in a TNS system if the main circuit breaker in a distribution panel is a 03 pole circuit breaker?
wrote on August 2, 2016
at
4:57 PM
Hi Sir,
Is there any Philippine standard as to what should be the rating of electrical plugs on devices?
Is there any Philippine standard as to what should be the rating of electrical plugs on devices?
Admin Reply by: Ver Pangonilo
Check this:
PNS 1572 - Plug and socket-outlets for domestic and similar general use. This is the same version as the IEC 83:1975 (http://www.elibrary.dti.gov.ph//DocumentFolder/pages%20from%201572%201997%20plugs%20&%20socket__00001.pdf)
PNS 1572 - Plug and socket-outlets for domestic and similar general use. This is the same version as the IEC 83:1975 (http://www.elibrary.dti.gov.ph//DocumentFolder/pages%20from%201572%201997%20plugs%20&%20socket__00001.pdf)
wrote on July 26, 2016
at
4:19 AM
Please Sir VER Pangonilo, I have 30,000 Watt Transformer with 220 VAC 3 Phase input to 220 VAC 3 phase output Isolation transformer, I not understand how to size the breaker so it will not occassionaly trip on power fail/restore some times when the power restores the breakertrips, currently it's a 250 amp breaker. - Thanks
Admin Reply by: Ver Pangonilo
A 30,000 watt 3-phase transformer assuming that it is at unity power factor has a full load primary current of 78.7 A or about 98.4 A at 80% PF. If your 250 A breaker is tripping, that is already 5 times the full load current of your transformer. You can do the following:
1) Check your loads when the breaker is tripping. Are you starting a motor load? Or any load that has a high in-rush current?
2). Check the trip setting of your circuit breaker.
3) Hire a competent electrician to do the work for you.
Replacing the circuit breaker with a higher rating is not an option unless there is an audit on your electrical system to determine that cable sizes are suitable for the new size of your circuit breaker.
If you can add more information, I may be able to help you better
1) Check your loads when the breaker is tripping. Are you starting a motor load? Or any load that has a high in-rush current?
2). Check the trip setting of your circuit breaker.
3) Hire a competent electrician to do the work for you.
Replacing the circuit breaker with a higher rating is not an option unless there is an audit on your electrical system to determine that cable sizes are suitable for the new size of your circuit breaker.
If you can add more information, I may be able to help you better
wrote on April 9, 2016
at
4:59 PM
Good day sir,
Familiar po ba kayo sa ANZSCO skill levels in australia and New zealand? since you are registered professional engineer in australia. ano po ba ang mga qualifications? Thanks and God Bless
Familiar po ba kayo sa ANZSCO skill levels in australia and New zealand? since you are registered professional engineer in australia. ano po ba ang mga qualifications? Thanks and God Bless
Admin Reply by: Ver Pangonilo
Sorry, I am not familiar with ANZCO. My qualifications was assessed through Engineers Australia (https://www.engineersaustralia.org.au/). Check their website for details.
wrote on April 9, 2016
at
9:43 AM
Good day sir,
pamilyar po ba kayo sa ANZSCO-Skill levels dyan sa Australia?. Thanks po and God Bless
pamilyar po ba kayo sa ANZSCO-Skill levels dyan sa Australia?. Thanks po and God Bless
wrote on April 5, 2016
at
11:36 AM
Good day sir,isa po akung Assistant Electrician sa cruise ship.gusto ko rin po maging Master Electrician.may suggest po ba kayo na review center o PEC 2009 na nka pdf?thank you sir.
Admin Reply by: Ver Pangonilo
Hi Noel,
Matagal na akong wala sa Pinas, di ko na alam ang kalakalan sa mga review centers.
Meantime, try this [https://filipinoengineer.com/wiki/Main_Page] . Keep in touch, I may be able to help one way or another.
Matagal na akong wala sa Pinas, di ko na alam ang kalakalan sa mga review centers.
Meantime, try this [https://filipinoengineer.com/wiki/Main_Page] . Keep in touch, I may be able to help one way or another.
wrote on March 14, 2016
at
3:06 PM
As per IEC 60445 clause can I use only black color code cable for three phase system.
Kindly suggest.
Kindly suggest.
Admin Reply by: Ver Pangonilo
Please clarify if you are referring to the outer sheath or conductor color?
Thanks
Thanks
wrote on December 10, 2015
at
9:48 AM
Welcome to my guestbook. Feel free to leave a message and I will reply as soon as I can. Thank you!
wrote on December 9, 2015
at
12:38 PM
Hi Sir,
Apologies for posting under the comments as I found that your contact page is not showing your contact form.
Magandang umaga po! Please allow me to introduce myself, I’m Elvis Abilay. I am a mechanical engineer by profession working as a senior mechanical engineer in an upstream oil and gas company in Singapore. I am also the founder of Filipinooilandgas.com.
Filipinooilandgas.com is developed to be an online, multi-discipline
community and resource hub for Filipinos working in the oil and gas
industry. The site offers technical/non-technical articles and essential resources that aim to assist its audience to be more globally competitive. It is designed to connect with all Pinoys around the world, and to help, unite and promote the workforce which we are a part of.
We are aware how helpful and how early you have started on your website. Ours are not even a year old but our aim is to leave this legacy of building camaraderie and being an instrument to connect every Filipino on this industry online. It may sound to be so daunting but at the same time fulfilling.
I am writing to you with the hopes of having a chance to get your support on this endeavour. It will mean a lot to us should you be interested in providing guest article on the site on topics about Electrical or be interviewed on our upcoming educational podcast. I am sure our audience will find your message very helpful. We will make sure you get all the credit on all your messages and link to your site and promote it.
Thank you for your time reading this message. Have a wonderful day ahead and GOD bless.
Regards,
Elvis Abilay
Apologies for posting under the comments as I found that your contact page is not showing your contact form.
Magandang umaga po! Please allow me to introduce myself, I’m Elvis Abilay. I am a mechanical engineer by profession working as a senior mechanical engineer in an upstream oil and gas company in Singapore. I am also the founder of Filipinooilandgas.com.
Filipinooilandgas.com is developed to be an online, multi-discipline
community and resource hub for Filipinos working in the oil and gas
industry. The site offers technical/non-technical articles and essential resources that aim to assist its audience to be more globally competitive. It is designed to connect with all Pinoys around the world, and to help, unite and promote the workforce which we are a part of.
We are aware how helpful and how early you have started on your website. Ours are not even a year old but our aim is to leave this legacy of building camaraderie and being an instrument to connect every Filipino on this industry online. It may sound to be so daunting but at the same time fulfilling.
I am writing to you with the hopes of having a chance to get your support on this endeavour. It will mean a lot to us should you be interested in providing guest article on the site on topics about Electrical or be interviewed on our upcoming educational podcast. I am sure our audience will find your message very helpful. We will make sure you get all the credit on all your messages and link to your site and promote it.
Thank you for your time reading this message. Have a wonderful day ahead and GOD bless.
Regards,
Elvis Abilay
Admin Reply by: Ver Pangonilo
Hi Elvis,
By all means, you have my support. Just let me know.
Thanks
Regards,
Ver
By all means, you have my support. Just let me know.
Thanks
Regards,
Ver