The mechanical effects of short-circuit currents in - Montefiore

8.6.1.2 Without calculation of the relevant
frequencies
Without consideration of the relevant frequencies, the
calculation is carried out using the maximum possible
values according to Table 2 of the standard.
a) Calculation of the short-circuit current forces
between the main conductors and between the
sub-conductors:
Y
a
F
Start
m (5,6)
m (2,3)
n = 1
a
F
N
s (7,8)
s (4)
b) Make available the factors α, β, and q:
α T3
β T3
q T4
137
c) Calculation of the stresses due to the forces
between the main conductors and due to the forces
between the sub-conductors; check of the shortcircuit
withstand of main conductors and subconductors:
Stop 2
Y
N σm ≤ qRp0,2
(11)
V σ V r = 1 T2
σ m (9)
n = 1
N
Y Y
V σs V rs = 1 T2
σ s (10)
σ s
σ tot (12)
σ tot
≤ Rp0,2 (14)
Y
N
≤ qR
N
p0,2
(13)
Stop 1
Stop 2