Unit substations are factory-assembled integrated units that include the transformer, primary switch or circuit breaker, and the secondary switchgear. When they are installed indoors, the transformer is usually a dry-type. It may be oil-filled if used outdoors or placed in an appropriate vault.
Unit substations are divided into primary and secondary types. Primary unit substations have a secondary voltage of 1,500 Volts or higher. Secondary unit substations have low voltage ratings of 600 Volts or less, and usually have a primary voltage rating of less than 15,000 Volts.
Advantages
Metal-Clad Switchgear
Lightning Protection & Over-Voltage
