Page 109 - Decision Making Applications in Modern Power Systems

Uncertainty analysis and risk assessment Chapter | 3 75

Start
Y
MT = 2E+8; λ;
μ; N = 1000; j = 1
Yes
is TTF 2
> (MT–CT)? X
V Yes
is j > N ? W
No
No No
is TTF 2 CT = CT+TTF 2 ;
CT = 0; OFF = 0; DT = 0; X < TTR 1 ? Generate TTR 2 and TTF 1
TTF 1= TTF 2 =TTR 1 = TTR 2= 0
Yes
Z
Failures j = OFF; CT = CT+TTF 2 ; OFF = OFF+1;
Generate TTF 1 DT = TTR 1 – TTF 2 + DT;
DownTime j = DT;
U j = DT/OFF; TTR 1= TTR 1 – TTF 2
Z A j = 1 –U j; Generate TTR 2
MTTF j = (MT – DT)/OFF; CTT = min (TTR 1 , TTR 2)
Z MTTR j = (DT)/OFF; j = j+1; DT = DT+CTT;
TTR 1= TTR 1 – CTT;
TTR 2= TTR 2 – CTT;
Yes V
is CT > MT ? X
No
No is TTR 2 = 0 ? Generate TTF 1
Yes
is TTF 1 X Yes
> (MT–CT)?
Z
Generate TTF 2
No
No
is TTF 1 CT = CT+TTF 1 ;
Z
< TTR 2 ? Generate TTR 1 and TTF 2
Yes
Y
CT = CT+TTF 1 ; OFF = OFF+1; W
DT = TTR 2 – TTF 1 + DT;
TTR 2= TTR 2 –TTF 1
Generate TTR 1
CTT = min (TTR 1 , TTR 2) U = mean (U j);
A = 1 – U;
DT = DT+CTT;
TTR 1= TTR 1 – CTT; MTTF s = mean (MTTF j );
TTR 2= TTR 2 – CTT; MTTR s = mean (MTTR j );
λ s=1/MTTF s ;
μ s= 1/MTTR s ;
No
is TTR 1 = 0 ? Generate TTF 2
Stop
Yes
Y
Generate TTF 1
Y
FIGURE 3.10 Flowchart for generating the failure rates and repair rates of the various modules
using MCS. MCS, Monte Carlo simulation.
TTF hw TTR hw TTF hw
TTF sw TTR sw
Module
failure
TTF hw : Time to failure for hardware
TTR hw : Time to repair for hardware
TTF sw : Time to failure for software
TTR sw : Time to repair for software
FIGURE 3.11 Monte Carlo model for the CPU module of the PMU. CPU, Central processing
unit; PMU, phasor measurement unit.