++++General:
     The  vacuum  circuit-breakers  of  type  VD4/S  are  intended  for  indoor  installation  in  air-insulated switchgear  systems.  They  have  a  switching  capacity  capable  of  handling  the  loads  occurring  at start-up and shutdown of equipment and plant units both in normal and in fault state.Vacuum  circuit-breakers  have  particular  advantages  for  use  in  networks  where  there  is  a  high switching  frequency  in  the  working  current  range  and/or  where  a  certain  number  of  short-circuit breaking  operations  are  expected.  T ype  VD4/S  vacuum  circuit-breakers  are  suitable  for autoreclosing, and have exceptionally high operating reliability and long life. The  vacuum  circuit-breakers  of  type  VD4/S,  designed  in  column  form,  can  be  supplied  both  as individualunits for switchgear T ype SM6, Uniswitch, HXGN, etc.
     Standards and specifications 
     Switchgear manufacture
     The  switchgear  complies  with  the  following  specifications  in  accordance  with  DIN,VDE  and  the relevant IEC publications: 
     • VDE0670, part1000 and IEC60694 
     • VDE0671, part100, and IEC62271-100. 
     • GB1984-2003 
     Installation  and  operation  The  relevant  specifications  are  to  be  taken  into  account  during installation and operation, particularly: 
     • DIN VDE0101, Power installations exceeding  AC1 kV 
     • VDE0105, Operationof electrical installations
     • DIN VDE0141, Earthing systems for special power installations with rated voltages above1 kV 
     •  Accident  prevention  regulations  issued  by  the  appropriate  professional  bodies  or  comparable organizations. 
     Operating conditions 
     Normal  operating  conditions  Design  to  VDE  0670,  part  1000,  “Common  specifications  for high-voltage switchgear and controlgear standards“ and IECpublication60694, with the following limit values: 
     •  Ambient temperature: 
     –Maximum +40℃
     –Maximum24 hour average +35℃
     –Minimum (according to “minus5 indoor class”) –5℃
    • Humidity: 
    –the average value of the relative humidity , measured over a periodof24 h, doesnot exceed95% 
    –the average value of the water vapour pressure, over a period of24 h, does not exceed2,2 kPa 
    –the average value of the relative humidity , over a period of one month, does not exceed90% 
    –the  average  value  of  the  water  vapour  pressure,  over  a  period  of  one  month,  does  not  exceed  1,8 kPa 
   • Maximum site altitude: ≤1000 M above sea level. 
    Specialoperating conditions: 
    Special operating conditions are to be agreed onby the manufacturer and user . The manufacturer must be consulted in advance about each specialoperating condition: 
  • Site altitude over1000 m: 
   –Allow for the reduction in the dielectric strengthof the air . 
  • Increased ambient temperature: 
  –Current carrying capacity is reduced. 
  –Provide additional ventilation for heatdissipation. 
  • Climate: 
  –A void the risk of corrosion or other damage in areas: 
  • with high humidity and/or
  • with major rapid temperature fluctuations. 
   –  Implement preventive measures (e.g. electric heaters) to preclude condensation phenomena 
++++Technical data:

 Guideline values for function times: