Description
Composition
Structurally , the NKU can consist of:
introductory cabinet;
sectional cabinet;
шкафа отходящих линий;
condenser unit cabinet (KRM cabinet);
soft starter cabinet (UPP cabinet);
cabinet of frequency-controlled drive (cabinet of CRP).
The number of cabinets can be any and in any configuration, there can be one cabinet from the above listed. The composition may vary depending on the terms of reference. Cabinets can be arranged in one line (one-way arrangement), or in two lines with a connection between them using a cable or a bus bridge (two-way arrangement). Busbars are laid inside the cabinet along the back wall.
CABINET COMPOSITION NKU
INTRODUCTORY CABINET
The input can be carried out both by cable (top and bottom) and by tires on top. For switching primary
following standard circuits can be used combinations of switching devices:
- automatic switch of stationary design;
- disconnector and automatic switch of stationary design;
- automatic switch of pull-out or plug-in design;
-load switch and fuses.
Current transformers, ammeters, voltmeters, counters can be installed to organize the accounting and display of parameters.
SECTIONAL CABINET
the following standard switching combinations can be used for switching primary circuits
devices:
- automatic switch of stationary design;
- disconnector, stationary circuit breaker and disconnector;
- automatic switch of pull-out or plug-in design;
- disconnector;
- load switch.
To implement the possibility of automatic input of a reserve in case of voltage loss at one of the inputs (if there are more than one), it is possible to install an AVR unit and motor drives on circuit breakers.
CABINET OF OUTGOING LINES
depending on the required current, it is possible to install one or more switching devices according to the following combinations.
- automatic switch of stationary design;
- disconnector and automatic switch of stationary design;
- automatic switch of pull-out or plug-in versions;
- load switch;
- disconnector with fuses.
For each line, it is possible to display current, voltage and keep electricity records.
KRM CABINET
designed to increase the power factor in the network. This event is required for industrial enterprises whose main electrical receivers are asynchronous motors. Circuit breaker, capacitors, contactors, etc. The result of these actions is:
- reducing the load on transformers, and consequently increasing their service life;
- reducing the load on wires, cables, tires, which reduces active heating losses and allows for-
change them with a smaller cross section;
- reducing the load on the switching equipment;
- exclusion of penalties for reduced power factor;
- reduction of electricity costs;
- voltage drop reduction.
To compensate for the reactive power in the NKU, there are KRM cells. Their use is due to such positive qualities as: minimum maintenance during the entire service life, small own active losses, a wide range of denominations and the possibility of automatic regulation.
When using the KRM cell as part of the NKU will RETURN or connecting to the busbars of an existing RUN, it is mandatory to install an automatic switch and a load switch in the cell. If the cell is connected to a free outgoing line of an existing RUNN, then the switching device can be excluded. All capacitors are protected by fusible inserts and have built-in protection against overpressure (by disconnection method).