Speedfax 2017

Secondary Unit Substations
Overview
General
14
SWITCHGEAR
Siemens offers a wide variety of unit
substation designs to meet customer
requirements. A unit substation
consists of one or more transformers
mechanically and electrically
connected to and coordinated in
design with one or more switchgear or
switchboard assemblies. A secondary
unit substation is defined as a unit
substation whose outgoing section is
rated below 1000 volts.
A typical secondary unit substation
consists of three sections:
n Primary: an incoming section that
accepts incoming high voltage (2400 to
13,800 volts) line
n Transformer: section that transforms
incoming voltage down to utilization
voltage (600 volts or less)
n Secondary: an outgoing section that
distributes power to outgoing feeders
and provides protection for these
feeders (600 volts and less)
Standard secondary unit substations
consist of:
n Medium-voltage Primary
n Transformer
n Low-voltage Secondary
Siemens also offers low-voltage unit
substations with:
n Low-voltage Primary
n Transformer
n Low-voltage Secondary
The primary reason for using a secondary
unit substation is to bring power as close
as possible to the center of the loads.
Another reason is that it provides a
system design concept incorporating a
wide variety of components that permits
tailoring equipment to the needs of the
application. A secondary unit substation
provides
n Reduced power losses
n Better voltage regulation
n Improved service continuity
n Increased functional flexibility
n Lower installation cost
n Efficient space utilization
Every component and assembly of
secondary unit substations are designed
and engineered as an integral part of a
complete system.
Primary Switch
Liquid Filled Transformer
Switchboard with WL Encased
Systems Breakers
Primary Switch
Dry Type Transformer
Type SB3 Switchboard with
Fusible Switches
Primary Switch
Liquid Filled Transformer
Type WL Low-voltage
Switchgear
For more information, please visit http://automation.usa.siemens.com/consultant/ or contact your local sales office.
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Siemens Industry, Inc. SPEEDFAX Product Catalog