METREL EurotestXC MI 3152, Instruction Manual

Page: 122 / 203

MI 3152(H) Eurotest XC (2,5 kV) Tests and measurements
121
The prospective short-circuit currents I
Min
, I
Min2p
, I
Min3p
and I
Max
, I
Max2p
, I
Max3p
are calculated as
follows:
𝐼
𝑀𝑖𝑛
=
𝐶
𝑚𝑖𝑛
𝑈
𝑁(𝐿−𝑁)
𝑍
(𝐿−𝑁)ℎ𝑜𝑡
where
𝑍
(𝐿−𝑁)ℎ𝑜𝑡
= √(1.5 × 𝑅
(𝐿−𝑁)
) 2 + 𝑋
(𝐿−𝑁)
2
𝐶
𝑚𝑖𝑛
= {
0.95; 𝑈
𝑁(𝐿−𝑁)
= 230 𝑉 ± 10 %
1.00; 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝐼
𝑀𝑎𝑥
=
𝐶
𝑚𝑎𝑥
𝑈
𝑁(𝐿−𝑁)
𝑍
(𝐿−𝑁)
where
𝑍
(𝐿−𝑁)
= √𝑅
(𝐿−𝑁)
2
+ 𝑋
(𝐿−𝑁)
2
𝐶
𝑚𝑎𝑥
= {
1.05; 𝑈
𝑁(𝐿−𝑁)
= 230 𝑉 ± 10 %
1.10; 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝐼
𝑀𝑖𝑛2𝑝
=
𝐶
𝑚𝑖𝑛
𝑈
𝑁(𝐿−𝐿)
𝑍
(𝐿−𝐿)ℎ𝑜𝑡
where
𝑍
(𝐿−𝐿)ℎ𝑜𝑡
= √(1.5 × 𝑅
(𝐿−𝐿)
)
2
+ 𝑋
(𝐿−𝐿)
2
𝐶
𝑚𝑖𝑛
= {
0.95; 𝑈
𝑁(𝐿−𝐿)
= 400 𝑉 ± 10 %
1.00; 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝐼
𝑀𝑎𝑥2𝑝
=
𝐶
𝑚𝑎𝑥
𝑈
𝑁(𝐿−𝐿)
𝑍
(𝐿−𝐿)
where
𝑍
(𝐿−𝐿)
= √𝑅
(𝐿−𝐿)
2
+ 𝑋
(𝐿−𝐿)
2
𝐶
𝑚𝑎𝑥
= {
1.05; 𝑈
𝑁(𝐿−𝐿)
= 400 𝑉 ± 10 %
1.10; 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝐼
𝑀𝑖𝑛3𝑝
=
𝐶
𝑚𝑖𝑛
× 𝑈
𝑁(𝐿−𝐿)
√3
2
𝑍
(𝐿−𝐿)ℎ𝑜𝑡
where
𝑍
(𝐿−𝐿)ℎ𝑜𝑡
= √(1.5 × 𝑅
(𝐿−𝐿)
)
2
+ 𝑋
(𝐿−𝐿)
2
𝐶
𝑚𝑖𝑛
= {
0.95; 𝑈
𝑁(𝐿−𝐿)
= 400 𝑉 ± 10 %
1.00; 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒
𝐼
𝑀𝑎𝑥3𝑝
=
𝐶
𝑚𝑎𝑥
× 𝑈
𝑁(𝐿−𝐿)
√3
2
𝑍
(𝐿−𝐿)
where
𝑍
(𝐿−𝐿)
= √𝑅
(𝐿−𝐿)
2
+ 𝑋
(𝐿−𝐿)
2
𝐶
𝑚𝑎𝑥
= {
1.05; 𝑈
𝑁(𝐿−𝐿)
= 400 𝑉 ± 10 %
1.10; 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒