Type IST off-load switchs are suitable for use in tropical zone, with a maximum ambient temperature of approximately 40
degrees Centigrade and an average temperature of approximately 28 degrees Centigrade with high humidity and heavy rainfall.
The preferred operational altitude is up to 1800 m above sea level.
|S.No ||DESCRIPTION ||UNITS ||BIDDER OFFERED VALUE |
|1. ||Rated Voltage ||KV ||12 KV |
|2. ||Frequency ||Hz ||50 Hz |
|3 ||Rated continuous current ||A ||630 |
|4 ||Impulse withstand voltage to ground ||KV ||95 |
|5 ||Impulse withstand voltage across gaps ||KV ||110 |
|6 ||Dry one-minute power frequency withstand voltage to ground ||KV ||35 |
|7 ||Dry one minute power frequency withstand voltage across gap ||KV ||45 |
|8 ||Wet one minute power frequency withstand voltage to ground ||KV ||30 |
|9 ||Limits of radio interference 10KV and 1000 K.C/Sec || ||250 uV |
|10 ||Temperature rise at rated current (max.) || ||30oC at 50oC ambient |
|11 ||Dimensions and mechanical ,Electrical |
values Of Polymer Insulator
| || |
|12 ||Leaking distance ||mm || 508 (minimum) |
|13 ||Dry arcing distance ||mm ||210 (minimum) |
|14 ||Cantilever strength ||kg ||400 |
|15 ||Tensile strength ||kg ||1000 |
|16 ||Compressive strength ||kg ||5400 |
|17 ||Tensile proof test load ||kg ||700 |
|18 ||Dry power frequency flashover ||KV ||85 |
|19 ||Wet power frequency flashover ||KV ||55 |
|20 ||Dry one-minute power frequency withstand ||KV ||70 |
|21 ||Wet one-minute power frequency withstand ||KV ||45 |
|22 ||Impulse flash over positive ||KV ||115 |
|23 ||Impulse flashover negative ||KV ||140 |
|24 ||Power frequency puncture voltage ||KV ||150 |
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 50oC
ii) Maximum daily average temperature 45oC
iii) Minimum ambient air temperature 0oC
iv) Maximum sun temperature on exposed Horizontal surface 60oC
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.) 30oC at 50oC 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:
- 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.