SecoGear 24kV-27kV Air Insulation Switchgear
11
Enclosure design and equipment
Typical modules (Figures 3/1)
With withdrawable type SecoVac VB2 Plus Vacuum
Circuit Breaker installed, SecoGear panels are used for
incoming or outgoing feeder. Each unit consists of three
high voltage compartments; Main bus bar, Circuit breaker,
Cable compartment and one Low voltage compartment for
instruments and auxiliary circuits.
For busbar sectionalizing, two panels are necessary, the
coupling panel with the withdrawable circuit breaker part and
a bus riser panel (available with busbar metering and earthing).
In equipment without busbar sectionalizing, a direct bar
connection between the individual panels will be provided.
Figure 3/1: Typical modules
Enclosure and partitioning
High quality 2mm thick Alu-Zinc steel sheets is used for the
external enclosure and internal partitions. Pressure relief
flaps are provided on the top of the panel for all high voltage
compartments. In case of overpressure due to internal arc
inside any of the compartments, these pressure relief flaps are
designed to open quickly to release the pressure. The pressure-
relief flaps are secured with steel screws on one side and
with plastic screws on the other side. In the case of internal
overpressure, the plastic screws are the point of rupture caused
by arc conditions. The top mounted pressure relief flaps on the
enclosure are made from mesh metal.
All compartments are accessible from the front, with their
own independent doors. The front doors can be opened up to
an angle of 130
°
and they are arc resistant. An inspection
window made of security glass is provided on circuit breaker
compartment door. The panel design provides an air gap
between two adjacent panels after panels are joined together.
•
Figures of the panel (Refer to figure 3/2), the floor of the cable
compartment is fitted with removable non-magnetic metal
(13).
•
The rear wall of the busbar compartment (3), intermediate
wall (14), mounting plate with shutters (16) and horizontal
partition (20) form part of the internal partitioning.
•
The earthed internal partitioning ensures safe access to the
circuit breaker and cable compartment (C) even when the
busbars are energized.
•
The low voltage compartment (D) is fully protected from the
high voltage area with the earthed steel-sheet casing.
•
On the end sides of the switchgear, end cover plates are
provided for consistent appearance, as well as mechanical
and thermal strength in case of internal arc fault in the end
panel.
•
Doors, rear walls and cover plates are treated against
corrosion and then coated with high quality paint. The doors
for circuit breaker and cable compartment are arc resistant
with a mechanical interlock.
