44 entries.

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?

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

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.

Hi may question lang po. Anu difference ng. 400v/230v system and 460v/230v syatem

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]

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

Where to find a book?

Philippine Electrical Codes Volume 1

Thanks,

Philippine Electrical Codes Volume 1

Thanks,

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

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?

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

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..

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?

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

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

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.

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

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.

I have to know about design of two winding transformer.

SC Voltage

Isc

%imp

SC Voltage

Isc

%imp

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.

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