7 Electrical Components used in power sub station │Electronicsinfos

What is an Electrical Substation?

    7 Electrical Components used in power sub station │Electronicsinfos

    An electrical substation system serves as a bridge between the power generation stations and the end consumers. An electrical substation is a key part of the power generation, transmission, and distribution system. It transforms voltage from high to low, or the reverse, depending on the power system's needs.

    Substations are equipped with transformers, circuit breakers, and other necessary equipment to manage the flow and quality of electricity. They serve as nodes where power may be redirected, regulated, or monitored before it continues to its destination.

    Types of Substations 

    There are different types of substations including
    • Step-up Substation 
    • Step-down Substation
    • Primary Substation
    • Secondary Substation
    • Distribution Substation
    • Switching Substation
    • Converter Substation 
    • Collector Substation

    Several components are integral to electrical substations, each playing a critical role in managing voltage levels and ensuring the safe distribution of electricity. Instrument transformers like Current Transformers (CTs) and Potential Transformers (PTs) are employed to accurately measure electrical quantities. 

    Insulators are pivotal as they provide insulation between conductors, ensuring electrical safety. Relays are essential for fault detection and signalling, contributing significantly to the reliability of the substation's operation.

    They are also equipped with circuit breakers to protect the distribution system and can be used to control the flow of current in different directions. we used a Bus bar to distribute electricity in different feeders. lightning Arrester is used to protect the overall system from lightning.

    7 Electrical Components

    1. Electrical transformers
    2. Instrument transformers
    3. Insulators
    4. Relays
    5. Bus bars
    6. Circuit Breakers
    7. Lightning Arrester

    Electrical transformers 

    Electrical transformers are fundamental components in the transmission and distribution of electrical power. They operate on the principles of electromagnetic induction.

    Essentially, transformers can either increase (step up) or decrease (step down) the voltage levels of alternating current (AC) in power systems.

    Types of transformers

    1. step-up transformer
    2. step down transformer

    Step-up Transformer

    A Step-Up Transformer is a type of transformer in which the primary voltages are lower than its Secondary voltage

    7 Electrical Components used in power sub station │Electronicsinfos
    Step up Transformer

    Step down Transformer

    A Step-Down Transformer is a type of transformer in which the primary voltage is more than its Secondary voltage

    7 Electrical Components used in power sub station │Electronicsinfos
    Step down Transformer
    To read More About Transformers 

    Instrument transformers

    Instrument transformers are essential components in the measurement and control of electrical power systems. There are two primary types of instrument transformers: current transformers (CT) and voltage transformers (VT), also known as potential transformers (PT). 

    Current transformers are designed to convert high currents to a lower, standard value that can be easily measured by ammeters, while voltage transformers step down voltage levels for measurement by voltmeters. 

    There are two main types of Instrument Transformer

    1. Current Transformer
    2. Potential Transformer

    Current Transformer

    A current transformer (CT) is a device in the field of electrical engineering, used to measure the current in a conductor without the need to make direct contact with it. This type of transformer produces a secondary current that is proportional to the primary current.

    CTs are commonly used in metering and protective relays in electrical power systems, and they come in various types such as wound, toroidal, and bar.

    7 Electrical Components used in power sub station │Electronicsinfos
    Current Transformer

    Ratings of C.T

    1. The ratings of secondary current are 5 A or  1A  for measurements.
    2. The Primary Current is up to 49000A.

    potential transformer

    A potential transformer, also known as a voltage transformer, is an instrument transformer that steps down high voltages to lower values for measurement, protection, and control in power systems. 

    These transformers are essential for the accurate monitoring of electrical systems, ensuring that voltage levels are within safe operating limits. They operate on the principle of electromagnetic induction.

    Potential transformers are designed with precision to maintain an accurate voltage ratio and phase relationship between the primary and secondary windings, which is crucial for the reliability of the measurements they provide.

    7 Electrical Components used in power sub station │Electronicsinfos
    Potential transformer

    Ratings of P.T

    1. The rating of the Secondary voltage is 120 volts.
    2. The primary ratings are up to 24,000 volts.


    An Electrical insulator is one in which electric current does not flow freely. there are different types of electrical insulators used in power substations. there are many types of insulators such as tension insulators, low-tension insulators, substation insulators, and special types of insulators. insulators are made from different insulating materials just as porcelain, mica, plastics, paper, wood etc. Insulators are also manufactured in different shapes and sizes.

    7 Electrical Components used in power sub station │Electronicsinfos
    Types of Electrical Insulators 


    Relay plays an important role in electrical substations .its used to protect the system. relay is an electrically operated device. there are two contacts of relays one is normally open(NO) contact and the other is normally close(NC) There are different sizes and shapes of relays.

    7 Electrical Components used in power sub station │Electronicsinfos
    Electrical Relays

    Types of Relays

    1. Electromagnetic Relays.
    2. Electronic Relays.
    3. Electromechanical Relays
    4. Reed Relays
    5. Time Delay Relays
    6. High-Voltage Relays
    7. Small Signal Relays

    Bus bars

    A busbar is a metallic bar used for local high-current power distribution. they are used in typically inside switchgear and panel boards. There are many types of busbar schemes used in substations.

    7 Electrical Components used in power sub station │Electronicsinfos
    Bus Bar 

    Sizes of Busbar

    There are different sizes of busbars.
    • 40x4mm
    • 40x5mm
    • 60x8mm 
    • 50x6mm 
    • 80x8mm 

    Materials of busbar

    Circuit Breakers

    A circuit breaker is a device that works in normal and abnormal conditions To secure the electrical system. A circuit breaker is used to make and break the electrical system. There are different sizes, shapes and ratings of Circuit breakers. the circuit breaker categories as Indoor circuit breaker and outdoor circuit breaker w.r.t services.

    Types of Circuit Breakers W.r.t construction

    There are three types of circuit breakers including

    1. Oil circuit breaker
    2. Air circuit breaker
    3. Vacuum circuit breaker
    4. SF6 circuit breaker
    7 Electrical Components used in power sub station │Electronicsinfos
    Types of Circuit Breaker

    Types of Circuit Breakers W.r.t voltages 

    There are three types of circuit breakers regarding voltages including

    1. High voltage circuit breaker(HV)
    2. Medium voltage circuit breaker(MV)
    3. Low voltage circuit breaker(LV)

    Lightning Arrester

    A lightning arrester is a component that protects from the damaging effects of lightning. there are different types of lightning arrestersThey are used in towers, transmission poles, buildings and substations.

    7 Electrical Components used in power sub station │Electronicsinfos
     lightning arrester

    Types of Lightning Arrester

    • Horn Gap Arresters
    • Valve-Type Arresters
    • Pellet-Type Arresters


    These components work together to smooth the operation of power systems, ensuring that electricity is safely and effectively delivered from generation points to end consumers. Each component plays a specific role in maintaining the stability and efficiency of the electrical supply.

    Frequently Asked Questions – FAQs

    What is the role of a circuit breaker in a substation?

    A circuit breaker is a protective device used to interrupt the flow of electricity in case of overloads or faults.

    How do transformers function in substations?

    Transformers are used to step up or step down voltage levels.

    Why are busbars important in substations?

    Busbars provide a low-resistance path for electrical current, enabling the distribution of power to various components within the substation.

    What role do capacitors play in substation equipment?

    Capacitors are used for power factor correction, helping to balance reactive power and improve the overall efficiency of electrical systems.

    How do protection relays contribute to substation safety?

    Protection relays monitor electrical parameters and act as sensors to detect abnormalities or faults.

    Why are voltage regulators necessary in substations?

    Voltage regulators ensure a stable output voltage within specified limits to maintain a reliable power supply.

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