Pressure Relief Ducts - ABB UniGear ZS1 Instruction Manual

2.2
Figure 84: 24 kV panels - Top-mounted box with earthing switch for busbar earthing. The arrangement is the same as
the figure above
2.2 Flat branch conductor for earthing switch
77 Top-mounted box for earthing switch
78 Operating mechanism box
78.1 Hexagonal shaft

5.8 Pressure relief ducts

54
The standard solution provided for the arc-proof version of the UniGear ZS1 consists of a metal sheet
duct for collecting and exhausting the hot gases; this duct is mounted on the upper side of the
switchgear and normally it is extended on both the right and left extremities
This solution is capable to guarantee the safety for the persons that are standing in front of the
switchgear, according to the IEC 62271-200 Standard (criteria 1 to 5).
The recommended solution in order to avoid the exhausting of the gases and the overpressures inside
of the switchgear installation room is to prolong the exhaust duct outside of the substation (from left
and right sides or front and rear sides). In this case, take care of the accessibility of the persons in the
gas-exhausting zone and protect the gas exhaust channel extremity in order to avoid the entrance of
water, dust, small animals and any foreign object.
UniGear ZS1 switchgear is available with the following solution of gad duct:
• Standard duct;
• Compact duct;
• Compact duct with top chimneys.
The pressure relief duct is supplied dismantled in single parts. The rear and front wall correspond, as
far as length is concerned, with the appropriate panel width. They are joined together by means of the
attachment strips.
The screw fixing material is contained in the "pressure relief duct" set of bags. Rivet nuts are already
provided in the metal sheets.
Note
The rear pressure relief flap must be mounted according to figure 85.
Details regarding connection to the wall and a discharge grating for pressure relief outside the
switchroom will be agreed on with the customer.
77
78.1 78