How does the Siemens 8DJH switchgear operate?

The 8DJH control boards are function-related. They integrate operation, mimic diagram and position indication. Further more, indicating, measuring and monitoring equipment as well as locking devices and local-remote switches are arranged according to the panel type and version. The ready for-service indicator and rating plates are fi tted in accor dance with the panel blocks.

Operation is identical for transformer and circuit-breaker feeders. First, the operating mechanism must be charged; then, closing /opening is done through separate pushbut tons. The condition of the energy store is indicated.

All actuating openings are functionally interlocked against each other, and are optionally lockable. Separate operating levers for the disconnecting and earthing function are optionally available.



1 8DJH Manual operation of load-break function

2 Locking function (option for ring-main feeders)

3 Manual operation of earthing function

4 Panel designation label

5 Position indicator for switch-disconnector

6 Position indicator for earthing switch

7 Sockets of capacitive voltage detecting system

8 “Fuse tripped” indicator

9 ON pushbutton for transformer or circuit-breaker function

10 OFF pushbutton for transformer or circuit-breaker function

11 Manual spring charging

12 “Spring charged” indicator

13 Position indicator for circuit-breaker

Features

• Switch positions: CLOSED – OPEN – EARTHED

• Switching functions as general-purpose switch disconnector (class E3) according to– IEC / EN 62271-103/ VDE 0671-103– IEC / EN 62271-102 / VDE 0671-102

• Designed as a three-position switch with the functions – Switch-disconnector and – Make-proof earthing switch

• 8DJH Operation via rotary bushing welded gas-tight into the front of the switchgear vessel

• Climate-independent contact in the gas-fi lled switchgear vessel

• Maintenance-free for indoor installation according to IEC / EN 62271-1 / VDE 0671-1

• Individual secondary equipment.

Mode of operation

The operating shaft forms one unit together with the three contact blades. Due to the arrangement of the fi xed contacts (earth – busbar), it is not necessary to interlock the CLOSE and EARTHING functions.

Closing operation

During the closing operation, the operating shaft with the moving contact blades changes from the “OPEN” to the “CLOSED” position. The force of the spring-operated mechanism ensures a high operator-independent closing speed and a reliable connection of the main circuit.

Opening operation

During the opening 8DJH operation, the arc is caused to rotate by the arc-suppression system. This rotation movement pre vents the development of a fi xed root.

The isolating distance in gas established after breaking fulfi lls the conditions applicable to isolating distances in accordance with– IEC / EN 62271-102 / VDE 0671-102 and – IEC / EN 62271-1 / VDE 0671-1.Due to the arc rotation caused by the arc-suppression system, both load currents and minor no-load currents are safely interrupted.

Earthing operation

The EARTHING operation is implemented by changing from the “OPEN” to the “EARTHED” position.

Features

• Mechanical endurance of more than 1000 operating cycles
• Parts subjected to mechanical stress are highly corrosion-proof

• Manual operation with the help of a slip-on operating lever
• Option: Motor operation
• Control board with accordingly cut-out switching gate prevents the three-position switch disconnector from being switched directly from the “CLOSED” via the

“OPEN” to the “EARTHED” position

• Two separate actuating openings are provided for unambiguous selection of the DISCONNECTING and EARTHING functions
• Operation via rotary movement, operating direction according to IEC / EN 60447 / VDE 0196 (FNN recommen dation, former VDN / VDEW recommendation).

• Spring-operated mechanism

  The switching movements are performed independently of the operating speed.

  Spring-operated/stored-energy mechanism

  The switching movements are performed independently of the operating speed.

  During the charging process, the closing and opening

  springs are charged. This ensures that the switch-discon nector/ fuse combination can switch off all types of faults reliably even during closing.

  8DJH Closing and opening is done via pushbuttons, and is there fore identical with the operation of circuit-breaker operat ing mechanisms.

  An energy store is available for tripping by means of an

  operating HV HRC fuse or via a shunt release (f-release).

  After tripping, a red bar appears on the position indicator.