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What is Substation and How Do They Work?

What is Substation and How Do They Work?

What is Substation and How Do They Work?

The need for electrical power is quickly increasing at the moment, and power generating substations can meet it. Thermal, atomic, and hydro-electric power generating substations are examples of distinct types of power generating substations. Substations are being built in various places based on the availability of various resources, however these locations may not be as near to load centers as they could be. The load center may handle the actual power utilization. As a result, power transmission from the substation to load center locations is important. As a result, this function necessitates the use of high-capacity, long-distance transmission networks.

Power is generated reasonably efficiently at low voltage levels; yet, supplying power at high voltage levels is less expensive. A number of switching and transformation stations must be built between the generating station and the customer ends in order to maintain high and low voltage levels. These two stations are commonly referred to as electrical substations. In this article we will try to discuss types of substations and how they work.

Substations illustrated in a single line diagram:

The substation is illustrated in the picture below as a single line layout. The substation’s connection is segmented as follows:

  • Connection to input or power supply
  • Outgoing feeder for feeding other substations or switchgear in the system.
  • Connection to the power transformer
  • Connection to a voltage transformer for control and metering.

The circuit breaker is connected from the bus bar to each input and output circuit. Every side of the circuit breaker is equipped with an insulator. For measurement and protection, the current transformer is utilized. Both sides of the circuit breaker have current transformers so that the protective area covers the circuit breaker.

The transformer is linked to the bus bar and to the input line. Lightning or surge capturer are phase-by-ground connections at the entrance line as first device as well as the transformer and condenser terminal, the shunt reactor terminal and the generator terminal, and the big motor terminal for diversion of switching.

Substation types:

Step-Up substations:

This kind of substation receives the power from a near-producer plant. It uses a big power transformer to increase the voltage to the remote sites. In the substation, a transmission bus to a transmission line can be used to transmit power. This substation might also be a knock on the incoming electricity the plant receives. The power received can be utilized to power the plant’s apparatus functioning. A substation incorporates switch-generation circuit breakers and, if necessary, transmission circuits in and out of service.

Customer substations:

This kind of substation is the main power supply for a particular corporate customer. Both the business case and technological requirements depend heavily on customers’ needs.

System Substations:

This substation covers the enormous quantity of power transfer across the station and is considered a system. These stations do not give transformers of electricity only when others swap voltage. These stations generally provide the endpoints for the transmission lines created from switchgear and provide the electric power for circuits providing transformer stations. For long-term consistency, it is crucial. These stations are both strategic and costly to install and maintain.

Distribution Type Substation:

Distribution substations are installed where the major voltage distributions are downgraded to provide consumers with voltages through a distribution network. Two phases will have 400 volts of voltage, with a voltage of 230 volts between neutral and either phase.

Step-down Type Substation:

This kind of substation is placed in an electrical network at various points. The network can connect many elements, which are a source of subdivisions or distribution lines. This type of transmission voltage can transform into a subtraction voltage (69kV). A supplier for distribution substations can be the converted voltage lines. In some circumstances, power is taken from the transmission line in order to be used on the road in an industrial capacity. Or else a substation is supplied with power.

Underground Distribution Substation:

Installing an urban substation takes a lot of area, but the substation often does not have a room to install. To solve this problem, the underground sub-station installation reduces the space need and surface area can also be used for other buildings, such as buildings, shopping centres, etc. The fundamental principle of the underground sub-station is to provide the best conventional substation by lowering the area occupied above the ground.


The switchyard is both the mediator and the generator and the switchyard can retain equal voltage. The primary aim is to supply energy generated from the power plant to the neighboring transmission line or power grid at a specific voltage level.

11kv Substation:

The main aim of the 11kv substation is to collect energy from the producer station at high voltage, and to reduce the voltage to a suitable local distribution value and supply switching equipment. This substation comprises insulating, lightning, step-down, CT metering, circuit breaker and condenser bank.

220 kV Substation:

The 220kVA substation is the power capacity of the step-down transformer in the substation, and it represents the maximum apparent power that a step-down transformer can deliver. This substation will receive a voltage level of 220kV.

132 kV Substation:

The 132 kV is the grade of a primary-voltage 132 kV step-down transformer. These transformers are generally used in substations of the transmission type when the voltage has to be downgraded to extra distribution.


Finally, we may assume from the preceding information that a subsystem is a key component of the power grid, forming a substantial connection between transmission, generation, distribution and load points.

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