Substation Role in the Power System
An electrical substation is a part of an electricity generation, transmission and distribution system where voltage is transformed from high to low or in reverse using transformers. It also serves as a point of connection between various power system elements such as transmission lines, transformers, generators and loads.
!!! To allow for flexibility in connecting the elements, circuit breakers are used as high power switches.
Electric power may flow through several substations between generating plant and the consumer and may be changed in voltage in several steps.
There are different kinds of substations such as Transmission substations, distribution substations, collector substations, switching substations and some other types of substations.
The general functions of a substation may include:
Connection point for transmission lines
Switchyard for network configuration
Monitoring point for control centre
Protection of power lines and apparatus
Communication with other substations and regional control centre
General Criteria for Substation Design
For the substation development to reach its technical and economical potential, the focus has moved now to studying how substations may enable more intelligence in the network, which is labelled the “smart grid” development.
It has been concluded that the 21st-century substation design should meet the following improved criteria: reliability, security, interoperability, reconfigurability, controllability, maintainability, flexibility, reduced cost and environmental impact. An estimate of the importance of the different criteria is shown in Figure 1.
The four major criteria commonly emphasized by substation designers are: reliability, cost, operational flexibility and environmental impact.