MV design guide - Schneider Electric

Presentation
Metal-enclosed,
factory-built equipment
To start with,
here is some key
information on MV switchboards!
reference is made to the International
Electrotechnical Commission
(IEC).
Introduction
In order to design a medium-voltage cubicle, you need to
know the following basic magnitudes:
c Voltage
c Current
c Frequency
c Short-circuit power.
The voltage, the rated current and the rated frequency are often known or
can easily be defined, but how can we calculate the short-circuit power or
current at a given point in an installation?
Knowing the short-circuit power of the network allows us to choose the
various parts of a switchboard which must withstand significant
temperature rises and electrodynamic constraints. Knowing the voltage
(kV) will allow us to define the dielectric withstand of the components.
E.g.: circuit breakers, insulators, CT.
Disconnection, control and protection of electrical networks
is achieved by using switchgear.
c Metal enclosed switchgear is sub-divided into three types:
v metal-clad
v compartmented
v block.
Schneider Electric
Merlin Gerin MV design guide
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