NOPOWSR 5976 GB
13
ABB / PTMV
SafeRing / SafePlus
SF6 insulated ring main unit and compact switchgear
Installation and operating instructions
4.4 GAS PRESSURE
SafeRing / SafePlus contains SF
6
gas with a nominal pressure
of
1.4
bar at 20
o
C.
SafeRing/ SafePlus is «sealed for life» and is fitted with a
temperature-compensated pressure indicator.
A temperature-compensated device that emits an electrical signal
to indicate lower pressure can be supplied on request.
Pointer in green area
- unit has correct pressure
Pointer in red area
- pressure is too low
5. OPERATION
5.1 OPERATING CONDITIONS
Normal ambient conditions
SafeRing / SafePlus is generally equipped for operation/service
in normal indoor conditions in accordance with IEC 60694.
The following limitations apply:
Ambient temperature
Max. temperature
+40°C
Max. temperature (24-hour average)
+35°C
Min. temperature
- 25°C
Humidity
Max. average relative humidity
measured over 24 hours
95%
Max. average relative humidity
measured over 1 month
90%
Max height above sea level for
installation without reducing gas pressure
1,000 metres
Special conditions
In accordance with IEC 60694, the manufacturer and end-user
must agree about special operating conditions which deviate
from operation under normal conditions.
The manufacturer/supplier must be consulted in advance if
especially difficult operating conditions are involved. When
electrical equipment is installed at more than 1,000 metres
above sea level, for example, the atmospheric pressure will be
lower and the overpressure in the tank will have to be reduced.
Airfreight
Units / modules delivered with redused overpressure - see
procedure for refilling.
NHP 408025
NOTE! Screw/unscrew
on this hexagonal nut only
Filling
pressure
mbar
SF
6
Air
1500
1400
1300
900
925
950
975 1000 1025 1050 1075 1100
Atm.
pressure
mbar
30°
25°
20°
15°
10°
ambient
temp.
Refilling of SF
6
gas in SafeRing/SafePlus
Following equipment is needed gas bottle with manometer and reduction
valve adapter pressure measuring device
1. Remove front cover and unscrew manometer as shown.
2. Screw (tightening the torque.45 Nm) the adapter to the valve.
3. Before connecting the hose from the gas bottle to the adapter, the air in
the hose must be removed by running SF
6
gas through the hose.
4. When gas is flowing into the RMU/switchgear, the manometer on the
gas bottle has to be observed. When it shows 0.4 bar at ambient
temperature 20° Celsius, (1,4 bar absolute) the gas filling must be
stopped. See table for filling pressure above.
5. Remove the filling hose and connect the pressure device to check the
pressure inside the RMU/switchgear.
6. When the correct pressure of 0.4 bar (1,4 bar absolute) is obtained,
remove the adapter and screw with tightening torque 45 Nm the
manometer to the RMU/switchgear as shown above.
Observe that the sealing between the manometer and the valve is
smooth and clean.
Valve
