Disconnecor Switch 12kv

1.0                       Scope & applications
 
1.1      The  pole-mounted Line Sectionalizer / Disconnector are open type, air insulated switch. The make and Break switching operation are performed at "zero system voltage." in "OFF LOAD"   condition, only for the isolation of the faulty circuits for the protection of 11 KV Distribution lines,   Transformers, Capacitors, Cables,  etc, from high transient lightening and surge Voltages.
 
1.2      The assembly of Gang operated three phase Pole Mounted Line Sectionalizer are supplied as a      single unit with single pole mounting arrangement. The unit are facilitate the installation of the   assembly on both sides (left or right) of the pole to operate and install the operating handle in      accordance with site conditions.    
 
2.0      System / conditions
 
i)                   Nominal system voltage                                    11 KV
ii)                 Highest system voltage                                     12 KV
iii)               Highest voltage for equipment                                 12 KV
iv)               BIL                                                     95 KV
v)                 Phases                                                 3 
vi)               Frequency                                           50 Hz
vii)             Rated Short circuit level of the system                     18 KA (1 second)
viii)           System Earthing: 11 KV Star point / Neutral solidly grounded at Pole / PMT:
 
3.0      Climatic conditions
 
i)                   Maximum ambient air temperature                          50^oC
ii)                 Maximum daily average temperature                   45^oC
iii)               Minimum ambient air temperature                           0^oC
iv)               Maximum sun temperature on exposed Horizontal surface   60^oC
v)                 Highest solar radiation intensity                               1000 W/m²
vi)               Maximum relative humidity                              95 %
vii)             Annual rain fall:                                                              20 to 60 mm in 2 to 4                                                           showers
viii)           Altitude                                                       Sea-level
ix)               Location                                                       Sea Coast (Interior is                                                   Semi-Desert).
x)                 Pollution                                           Severe marine pollution on                                                account of windblown                                                            sand and dust with salt                                                       content and salt laden                                                             spray and mist. Washing                                                 action by rain is negligible,                                                as rainfall is scanty.
 
4.0     Ratings and characteristics for line Sectionalizer
 
4.1      The Gang Operated pole mounted 11 kv Line Sectionalizer have the following ratings and characteristics based on 50 deg. C ambient temperature:
 
i)                               Nominal voltage                                               11 KV
ii)                             Maximum design voltage                                                 12 KV
iii)                           Rated continuous current                                              630  Amps
iv)                           Impulse withstand voltage to ground                              95 KV
v)                             Impulse withstand voltage across gaps                              110 KV
vi)                           Dry one-minute power frequency withstand voltage to ground       35 KV
vii)                         Dry one minute power frequency withstand voltage across gap          45 KV
viii)  Wet one minute power frequency withstand voltage to ground        30 KV
ix)                           Limits of radio interference 10KV  and 1000 K.C/Sec                250  uV
x)                             Temperature rise at rated current (max.)                                      30^oC at 50^oC ambient
 
 
4.2      Polymer insulator
 
The mechanical and electrical characteristics of the Polymeric insulator are as under:
 
 
 
 
 
4.2.1   Dimensions and mechanical values
 
i)                   Leaking distance                                        508 mm  (minimum)
ii)                 Dry arcing distance                                    210 mm  (minimum)
iii)               Cantilever strength                                     400  kg
iv)               Tensile strength                                          1000 kg
v)                 Compressive strength                                        5400 kg
vi)               Tensile proof test load                                      700  kg
                
4.2.2   Electrical values
 
i)                   Dry power frequency flashover                               85  KV
ii)                 Wet power frequency flashover                              55  KV
iii)               Dry one-minute power frequency withstand                   70  KV
iv)               Wet one-minute power frequency withstand                  45  KV
v)                 Impulse flash over positive                                   115  KV
vi)               Impulse flashover negative                               140  KV
vii)             Power frequency puncture voltage                          150  KV
 
 
5.0      Constructional features
The three pole disconnectors are mainly designed for a vertical mounting. The following elements could be changed or incorporated:
– Fuseholder.
– Earthing connection with locking device to prevent the connection to earth when the disconnector is closed or to close the device when the earth is connected.
– The earthing disconnector can be placed in the entrance or exit of the main switch.
– The earth disconnector is operating by means of an independent control.
– The operating axis could be placed at left or  right side.
– The operating axis could be extending until 250, 420,500, 750 or 1000mm, these extensions includes a support to avoid it bend down.
– The outdoor units are provided with different drills to permit the direct fixing to a post or to a frame previously fix to a post.