Megger NIM 1000, Руководство пользователя

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Technical Description
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2 Technical Description
2.1 System Description
The NIM 1000 serves to measure network impedance in low voltage grids. In this
process, the conductor connections are tested for their current carrying capacity while
subjected to typical operating loads and potential flaws are indicated.
With the help of the following range of preventative applications, a consistently good
supply quality can be guaranteed, outages prevented and adequate network rating
ensured:
• Preventative inspection and uncovering of faults (e.g. neutral conductor fault)
• Determination of the maximum connected / feed-in power
• Monitoring for secure shut-down (rating of fuses)
• Approval of new / modified network sections
Fault detection in low voltage grids is another area of application of the device. For
example, the NIM 1000 can be used to trigger a load-dependent fault which can then be
located either with the help of a simultaneously connected measuring device or by
means of multiple measurements at various connection points.
The device is linked to the low voltage grid to be tested by means of the available
connection cables (four-conductor measurement with Kelvin clips) and also receives its
supply voltage over these wires.
In preparation for a measurement, either a defined measurement period or a target
number of measurements can be specified.
To determine the network impedance, the adjustable load current is generated for a
short period by means of a semi-conductor circuit-breaker with the appropriate load-
resistor. The current and voltage curves are recorded immediately before and while
applying the load by means of A/D converters and then analysed by calculation. The
result is shown on the display.
When taking measurements on more than one phase, there is automatic switching
between the phases.
Intended use
Function