5. Mode of Operation
5.1 General
The type SGF two-column rotary disconnector has separate operating mechanisms for the
disconnector and the earthing switch.
Prevention of automatic operating or closing
When the equipments switched on or off, a dead-center position is passed through just before the end
positions are reached. This prevents the automatic opening or closing of the disconnector or earthing
switch as a result of :
l Short-circuit
l External influence : (e.g. storm or earthquake)
5.2 Disconnector
Operating mechanism :-
The operating mechanism (75) of the disconnector transfers the operating energy via the operating rod
(37) to the rotary pedestal (70). The diagonal rod (68) connects the two rotary pedestals of each pole.
Consequently, both pole halves are moved simultaneously.
The support insulators (201) transfer the torque to the two current-path halves (5, contact side) and (6,
0
finger side). These pass through an angle of rotation of 90 during switching.
Current transfer :-
During switching-on, the counter-contact (67) glides between the contact fingers (66). This establishes
the connection between the two current-path halves. The current is transferred via tulip-type contacts
in the rotary heads (284) to the high-voltage terminals (17).
Mechanical coupling inside a disconnector group :-
Via the coupling rods (15), the movement of the operated pole is transferred simultaneously to the other
poles of a disconnector group.
Figure 5 : Mode of operation of type SGF two-column rotary disconnector
(example : 3-pole in parallel arrangement)
6/113
1HDB 050016-YN-A
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