Fully gas insulated compact Ring Main Unit (GA)
- In the GA Ring Main Unit the primary switchgear and busbar are installed in a common gas tank.
- SF6 is used as insulation and extinguishing medium.
- The GA Ring Main Unit is designed with two cable panels and one transformer panel as standard.
- Connection to the distribution network is accomplished via load-break switches in the cable panels.
- Connection to the consumer is accomplished via the transformer panel to the main transformer.
- The GA Ring Main Unit has 2 to 4 panels and can be delivered in one of the following panel combinations.
The SF6 panels have four system elements
1) Electrical switching compartment
2) Drives mechanisms
3) Fuse compartment
4) Cable connection compartment
Fully Gas Insulated (GIS) Ring Main Unit passed all necessary tests carried out in The Egyptian
Electricity Authority Pyramids High Voltage Research Center and approved from The Egyptian
Electricity Holding Company.
The SF6 Ring Main Unit is designed, manufactured and tested in conformity
to the latest standards :
|Rated normal current|
|Busbars and cubicle interconnection||A||630|
|Output to transformer||200|
|Rated short-time withstand current|
|With tk = 1 s – 3 s||KA||20 / 25|
|Peak value||KA||50 / 63|
|Rated insulation level|
|Rated power-frequency withstand voltage (1 min)||KV||20||28||38||50|
|Rated lightning impulse withstand voltage||KV||60||75||95||125|
|Internal arc classification according to IEC 62271-200||AFL||AFL 20 KA 1 s|
|Degree of protection||IP65 (Gas tank) IP3XD / IP44 (Enclosure)|