Electrical power distribution is the final stage of an electrical power system, which entails the delivery of electricity to the load. The primary role of this section is to carry the electricity from the transmission lines to the loads in the individual customers to the different strata of society. In the power distribution section of an electrical power system, there are two main subsections: primary distribution and secondary distribution. Before we take a closer look at the nuances of an electric power substation, let’s take a look at its history to have a better understanding and appreciation for how far modern electric power distribution has come.
A distribution system consists of all the facilities and equipment connecting a transmission system to the customer’s equipment.
A typical distribution system can consist of:
- Substations
- Distribution Feeder Circuits
- Switches
- Protective Equipment
- Primary Circuits
- Distribution Transformers
- Secondary’s, and Services
Most industries need 2,400 to 4,160 volts to run heavy machinery and usually their own substation or substations to reduce the voltage from the transmission line to the desired level for distribution throughout the plant area. They usually require 3-phase lines to power 3-phase motors.
Commercial customers are usually served at distribution voltages, ranging from 14.4 kV to 7.2 kV through a service drop line which leads from a transformer on or near the distribution pole to the customer’s end use structure. They may require 3-phase lines to power 3-phase motors.
An electrical substation contains many types of equipment. Substation generally comprises the following equipment:
Power Transformers
Tap Changing Equipment
Circuit Breakers
Bus Bar, Bays and Steel Structures
Lightning Arrester
Circuit Switchers
Disconnect Switch / Isolator
Earth Switches
Current Transformer
Potential Transformer
Neutral Grounding Resistor
High-Voltage Fuses
Metal-Clad Switchgear
Shunt Reactors
Current-Limiting Inductor or Air Core Reactor
Line Trap
Coupling Capacitor Voltage Transformer
Control House
Control Panel
Substation Protective Relays
Supervisory Control
Remote Terminal Unit
Digital Fault Recorder
Capacitor Bank
Voltage Regulator
Power-Line Carrier Equipment
Microwave Equipment
Batteries
