tension controller 3BSE018105R1

tension controller 3BSE018105R1

tension controller 3BSE018105R1

The main purpose of switchgear interlocking is:

• To avoid the dangerous or damaging operation of switchgear

• To enforce restrictions on the operation of the substation for other reasons for example, load configuration. Examples of the latter are to limit the number of parallel transformers to a maximum of two or to ensure that energizing is always from one side, for example, the high voltage side of a transformer. This section only deals with the first point, and only with restrictions caused by switching devices other than the one to be controlled. This means that switch interlock, because of device alarms, is not included in this section. Disconnectors and earthing switches have a limited switching capacity.

Disconnectors may therefore only operate:

• With basically zero current. The circuit is open on one side and has a small extension. The capacitive current is small (for example, < 5A) and power transformers with inrush current are not allowed.

• To connect or disconnect a parallel circuit carrying load current. The switching voltage across the open contacts is thus virtually zero, thanks to the parallel circuit (for example, < 1% of rated voltage). Paralleling of power transformers is not allowed.