Comparison NSV-supply via in-line switch-disconnector-fuse or input isolator::

The following example demonstrates, how the spread of the isolines reacts if the supply takes places over an in-line-switch-disconnector-fuse or a input isolator (Sirco).

Description

Comparison of NS-distribution over in-line-switch-disconnector-fuse and input isolator:
Dimensions:  Width 2000mm, Depth: 400mm, Height: 2000mm
Input:           Center
In:               866A (630kVA transformer)
 ET_Sefag        ET_Sirco
Input with in-line-switch-disconnector-fuse
 
Input with input isolator (Sirco)

Isolines calculation

Isolines calculation with EFC400
Sefag_Sirco_Iso
Input with in-line-switch-disconnector-fuse Input with input isolator (Sirco)

Conclusion: The field propagation, when using an in-line-switch-disconnector-fuse, is much lower than when using an input isolator (Sirco-switch). Because of their construction, such input isolators cause strong stray fields. Isoline calculations of distributions, which have built in separators, therefore have to be calculated WITH the separator, whereby the geometry of the separator has to be exactly reproduced. Such separators can not be neglected in the calculation.


Comparison NSV-center input with lateral input::

In the following example the isolines spread of a NS-distribution with a center input and a lateral input is compared.


Description

Comparison of NS-distribution with center input and lateral input:
Dimensions:   Width: 2500mm, Depth: 400mm, Height: 2000mm
Input:           Center or lateral
In:                866A (630kVA transformer)
 Sirco_mitte        Sirco_links 
Left: Center input with Sirco
 
Right: Einspeisung links mit Sirco

Isolines calculation

Isolines calculations with EFC400
NSV_Mittel_Sirco_VO_Iso
Left: Center input (with Sirco) Right: Input left (with Sirco)

Conclusion: The field propagation is much lower with center input, because the current is divided to the right and to the left. For the lowest possible fields of NS-distributions, the center input should be chosen. In addition, the outlets with the highest currents should be placed right after the input. (Sirco-) Disconnectors should be omitted (see example “Comparison NSV-input”).



Distribution cabin correctly connected?::

Cable distribution cabins, which are found on every roadside, can be connected “right” or “wrong”. By “right” or “wrong” we refer here to the magnetic field strengths, which can vary considerably depending on the connection type. By a “right” connection of the cables, the magnetic field strengths can be reduced to a minimum, without additional effort or costs.

Technology: Place the input or ring in the center of the cabin, place the large consumer directly next to the input and the small consumer on the very outside..

Conclusion: It can be shown, as in the last example with 630A, that a reduction of the 1µT line of 2m, from 3.2m to 1.2m can be reached!

Current load 100A


Cable distributing cabin 9 elements

Charts:
Links: Input outside, right: Center input 
Florida 9 von vorne
Florida 9 von oben
Florida 9 von rechts
Florida 9 von rechts
Front view
left not optimized, right optimized
View from above
left not optimized, right optimized
View from right
not optimized
View from right
optimized


Current load 200A

Cable distributing cabin 9 elements

Charts:
Left: Input outside, right: Center input
Florida 9 vo Florida 9 vo Florida 9 vo Florida 9 vo
Front view
left not optimized, right optimized
View from above
left not optimized, right optimized
View from right
not optimized
View from right
optimized

Cable distributing cabin 13 elements

Charts:
Left: Input outside, right: Center input
Florida 13 vo Florida 13 vo Florida13 200A Florida13 RE 200A opt
Front view
left not optimized, right optimized
View from above
left not optimized, right optimized
View from right
not optimized
View from right
optimized

Cable distributing cabin 17 elements

Charts:
Left: Input outside, right: Center input
Florida 17 vo Florida 17 ob Florida 17 re Florida 17 re
Front view
left not optimized, right optimized
View from above
left not optimized, right optimized
View from right
not optimized
View from right
optimized

 Current load 400A


Cable distributing cabin 9 elements

Charts:
Left: Input outside, right: Center input
Florida 9 vo Florida 9 vo Florida 9 vo Florida 9 vo
Front view
left not optimized, right optimized
View from above
left not optimized, right optimized
View from right
not optimized
View from right
optimized

Current load 630A


Cable distributing cabin 9 elements

Charts:
Left: Input outside, right: Center input
Florida 9 vo Florida 9 vo Florida 9 vo Florida 9 vo
Front view
left not optimized, right optimized
View from above
left not optimized, right optimized
View from right
not optimized
View from right
optimized



NISV optimized NS-cable assembly::

Description

With an optimized layout of the Ns-cable the 1µT-line is significantly reduced. Cables with optimized arrangement and routing on the floor/in the cable cellar do not have to be specially shielded. However, cable routings on the ceiling remain critical. In this case, appropriate shielding measures are often unavoidable.
Comparison of the 1µT isolines at 1460 A:
leiteranordnung1
leiteranordnung
1µT-line at 200cm
Point symmetrical arrangement, conductor aloof
1µT-line at 95cm
Point symmetrical arrangement, conductor bound

Calculations

The following parameters were used for the calculations:
Cable manufacturer: Leoni Studer
Cable type:              Trafoflex Betaflamm
Cable cross section:  1x240mm²
Cable diameter:        31mm
In:                          866A
Comparison of bundled and point symmetric transfer:
866 gebuendelt  866 punktsym
Cable bundled and installed, 4x2x240mm Cable point symmetrically laid, 4x2x240mm

 

 


Comparison house distribution 1-pole or 3-pole protection machines::

 

In the following example, the isoline spread of an apartment distributor is examined.
Left: 1-pole circuit breakers on top of each other wired on top-hat rail
Right: 3-pole circuit breakers
Conclusion: With the best possible equipment and their arrangement, the field can be reduced up to a factor of 2.5.


Calculation

 

Comparison 1-pole machines are arranged on top of each other and 3-pole machines, input 3x25A
Hausverteiler 1p  Hausverteiler 3p
3 1-pole machines arranged below each other
3-pole machines
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