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.
Panel Structure:

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 :

IEC 60265-1
IEC 62271-1
IEC 60282-1

Rated Voltage KV7.51217.524
Rated FrequencyHZ50/60
Rated normal current
Busbars and cubicle interconnectionA630
Output to transformer 200
Rated short-time withstand current
With tk = 1 s – 3 sKA20 / 25
Peak valueKA50 / 63
Rated insulation level
Rated power-frequency withstand voltage (1 min)KV20283850
Rated lightning impulse withstand voltage KV607595125
Internal arc classification according to IEC 62271-200AFLAFL 20 KA 1 s
Degree of protectionIP65 (Gas tank) IP3XD / IP44 (Enclosure)
ColorGrey 7035