blob: 746c48c4226c8aae5a3a9256ba6e8144127778f5 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
|
// A Texbook on POWER SYSTEM ENGINEERING
// A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar
// DHANPAT RAI & Co.
// SECOND EDITION
// PART III : SWITCHGEAR AND PROTECTION
// CHAPTER 1: SYMMETRICAL SHORT CIRCUIT CAPACITY CALCULATIONS
// EXAMPLE : 1.6 :
// Page number 471
clear ; clc ; close ; // Clear the work space and console
// Given data
kVA_gen = 21000.0 // Generator rating(kVA)
kV_gen = 13.8 // Voltage rating of generator(kV)
X_tr_gen = 30.0 // Transient reactance of generator(%)
kVA_trans = 7000.0 // Transformer rating(kVA)
kV_trans_lv = 13.8 // LV voltage rating of transformer(kV)
kV_trans_hv = 66.0 // HV voltage rating of transformer(kV)
X_trans = 8.4 // Reactance of transformer(%)
l = 50.0 // Tie line length(miles)
x = 0.848 // Reactance of tie line(ohm/mile)
l_fault = 20.0 // Location of fault from station A(miles)
// Calculations
kVA_base = kVA_gen // Base rating(kVA)
kV_base_lv = kV_trans_lv // Base voltage on L.V side(kV)
kV_base_hv = kV_trans_hv // Base voltage on H.V side(kV)
Z_gen_pu = %i*X_tr_gen/100 // Impedance of generator(p.u)
Z_trans_pu = %i*X_trans*3/100 // Impedance of transformer(p.u)
Z_F_left = %i*x*l_fault*kVA_base/(kV_base_hv**2*1000) // Impedance of line to left of fault F(p.u)
Z_F_right = Z_F_left*(l-l_fault)/l_fault // Impedance of line to right of fault(p.u)
Z_AF = Z_gen_pu+Z_trans_pu+Z_F_left // Impedance(p.u)
Z_BF = Z_gen_pu+Z_trans_pu+Z_F_right // Impedance(p.u)
Z_eq = Z_AF*Z_BF/(Z_AF+Z_BF) // Equivalent impedance(p.u)
I_F = 1.0/abs(Z_eq) // Fault current(p.u)
I_base = kVA_base/(3**0.5*kV_base_hv) // Base current(A)
I_F_actual = I_F*I_base // Actual fault current(A)
// Results
disp("PART III - EXAMPLE : 1.6 : SOLUTION :-")
printf("\nActual fault current = %.f A \n", I_F_actual)
printf("\nNOTE: Changes in the obtained answer from that of textbook is due to more precision here")
|
