Short circuit calculation using MVA method (manual), [ diktrus ] - Hallo sobat blogger Pendidikan, Posting yang saya unggah pada kali ini dengan judul Short circuit calculation using MVA method (manual), [ diktrus ] , Artikel ini bertujuan untuk memudahkan kalian mencari apa yang kalian inginkan, kami telah mempersiapkan artikel ini dengan baik untuk kalian baca dan ambil informasi didalamnya. mudah-mudahan isi postingan Artikel Analisa Sistem Tenaga Listrik, Artikel Sistem Proteksi dan Pentanahan, Artikel Sistem Transmisi dan Distribusi, yang kami tulis ini dapat kalian pahami dengan baik, semoga artikel ini berguna untuk kalian, jika ada kesalahan penulisan yang dilakukan oleh penulis mohon dimaafkan karena penulis masih newbie. baiklah, selamat membaca.

Judul : Short circuit calculation using MVA method (manual), [ diktrus ]
link : Short circuit calculation using MVA method (manual), [ diktrus ]

Short circuit calculation using MVA method (manual), [ diktrus ]

By : Gusti  Anggara,

Maaf saya  tulis dalam bahasa inggris, karena ini saya belajar dari literatur berbahasa inggris.

Utility: 150KV, 1000 MVAsc

Transformer 1: 170 MVA, 150/13.8KV, 15% Z

13.8KV Bus

Generator: 100MVA, X"d = 0.2

Transformer 2: 30 MVA, 13.8/6.6KV, 15% Z

6.6KV Bus

Transformer 3: 2MVA, 6.6KV/400V, 10% Z

Motor 1: 10 MVA (Lumped), 20% Z

400V Bus

Motor2: 1000 KVA (Lumped), 20% Z

Motor 3: 600 KVA (Lumped), 10% Z

In the event of ashort circuit, thesources of short circuit current are

1. Utility

2. Generators

3. Motors

 Static loads such as heaters and lighting do not contributeto short circuit.

"EquivalentMVA" are:

Transformers and Motors

 Generators

 Cables and Reactors

So, here are the results of MVAsc:

Utility: MVAsc = 1000MVA

Transformer 1: MVAsc = 170 / 0.15 = 1133.33 MVA

13.8KV Bus

Generator: MVAsc = 100 / 0.2 = 500 MVA

Transnformer 2: MVAsc = 30 / 0.15 = 200 MVA

6.6KV Bus

Transformer 3: MVAsc = 2 / 0.1 = 20 MVA

Motor 1: MVAsc = 10 / 0.2 = 50 MVA

400V Bus

Motor 2: MVAsc = 1 / 0.2 = 5 MVA

Motor 3: MVAsc = 0.6 / 0.1 = 6 MVA

Now we calculate the upstream contribution :

At Transformer 1:

MVAsc @ 150KV = 1000 MVA

MVAsc @ 13.8KV = 1/ (1 / 1000 + 1 /1133.33) = 531.25 MVA

At Transformer 2:

MVAsc @ 13.8KV = 531.25 + 500 = 1031.25 MVA

MVAsc @ 6.6KV = 1/ (1 / 1031.25 + 1 / 200) = 167.51 MVA

At Transformer 3:

MVAsc @ 6.6KV = 167.51 + 50 = 217.51 MVA

MVAsc @ 400V = 1/ (1 / 217.51 + 1 / 20) = 18.31 MVA

At 400V Motors

Motor 3: MVAsc = 18.31 x 5 / ( 5 + 6 ) = 8.3 MVA

Motor 4: MVAsc = 18.31 x 6 / ( 5 + 6 ) = 9.98 MVA

The fault MVAsc @bus 400V = 18.31 + 5 + 6 = 29.31MVAsc

The three phase  I_f = 29.31/(1.732*(0.4)) = 42.3 kA.

Now we come to fault single phase to ground :

For single phase faults, positive sequence, negative sequence and zero sequence

impedances need to be calculated.

I_f = 3 (I1 + I2 + I0)

Examining the circuit in above, at the 400V Bus, on Transformer 3 contributes to the

zero sequence current.

For transformers, the negative sequence and zero sequence impedance are equal to the positive sequence impedance.

Z1 = Z2 = Z0 or

MVA1 = MVA2 = MVA0

@bus 400V;

1 / MVAsc =1/3 (1 / MVAsc1 + 1 / MVAsc2 + 1 / MVAsc0)

1 / MVAsc = 1/3 (1 / 29.31 + 1 / 29.31 + 1 / 20 )

1/ MVAsc = 

MVAsc = 1/   = 25.4 MVAsc

If= 25.4 / (1.732 x 0.4) = 36.6 kA

Demikianlah Artikel Short circuit calculation using MVA method (manual), [ diktrus ]

Sekianlah artikel Short circuit calculation using MVA method (manual), [ diktrus ] kali ini, mudah-mudahan bisa memberi manfaat untuk anda semua. baiklah, sampai jumpa di postingan artikel lainnya.

Anda sekarang membaca artikel Short circuit calculation using MVA method (manual), [ diktrus ] dengan alamat link http://diktrus.blogspot.com/2013/04/short-circuit-calculation-using-mva.html

Tweet