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
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| Input with in-line-switch-disconnector-fuse |
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Input with input isolator (Sirco) |
Isolines calculation
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| 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
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Left: Center input with Sirco
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Right: Einspeisung links mit Sirco
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Isolines calculation
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| 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
Current load 200A
Cable distributing cabin 9 elements
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Front view
left not optimized, right optimized
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View from above left not optimized, right optimized |
View from right
not optimized
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View from right
optimized
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Current load 400A
Current load 630A
NISV optimized NS-cable assembly::
Description
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Comparison of the 1µT isolines at 1460 A:
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1µT-line at 200cm
Point symmetrical arrangement, conductor aloof
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1µT-line at 95cm
Point symmetrical arrangement, conductor bound
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Calculations
Cable type: Trafoflex Betaflamm
Cable cross section: 1x240mm²
Cable diameter: 31mm
| Comparison of bundled and point symmetric transfer: | |
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| 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.
