blob: 7f4cc386f98482a2579aa05fa15f35a4831fa68c (
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
|
// 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 7: PROTECTIVE RELAYS
// EXAMPLE : 7.1 :
// Page number 595-596
clear ; clc ; close ; // Clear the work space and console
// Given data
I_setting = 150.0 // Current setting of IDMT(%)
t_mult = 0.5 // Time multiplier setting
ratio_CT = 500.0/5 // CT ratio
CT_sec = 5.0 // Secondary turn
I_f = 6000.0 // Fault current
// Calculations
I_sec_fault = I_f/ratio_CT // Secondary fault current(A)
PSM = I_sec_fault/(CT_sec*I_setting/100) // Plug setting multiplier
t = 3.15 // Time against this PSM(sec). From graph E7.1 in textbook page no 595
time_oper = t*t_mult // Operating time(sec)
// Results
disp("PART III - EXAMPLE : 7.1 : SOLUTION :-")
printf("\nTime of operation of the relay = %.3f sec", time_oper)
|
