The Comprehensive Guide to Electrical Substations: Design, Operation & Maintenance

Get an overview of design specifications & considerations for constructing an electrical substation. Learn about the different components and requirements for efficient, reliable operations.

Basics of an Electrical Substation

​An electrical substation is a vital part of the electrical grid. It is a point where electricity is generated, transformed, or distributed. The substation is the link between the generating plant and the transmission and distribution system.

The substation includes facilities for switching, controlling, and protecting equipment and circuits. The equipment may be installed indoors or outdoors. Indoor equipment is usually housed in air-insulated or gas-insulated switchgear buildings.

The first thing to understand about electrical substations is that they come in a variety of shapes and sizes. There are small substations that may only have a handful of pieces of equipment, while larger substations can have hundreds of pieces of equipment. The size of the substation will be determined by the amount of power that needs to be processed.

Substations can be classified by their function, voltage, and geography. The function of the substation will determine the type of equipment that is installed. For example, a generating station will have different equipment than a substation that is only responsible for distributing power.

The voltage at which the substation operates will also dictate the type of equipment that is used. For example, a high-voltage substation will require different equipment than a low-voltage substation.

Finally, the geography of the substation will also play a role in the type of equipment that is used. For example, a substation that is located in a cold climate will require different equipment than a substation located in a hot climate.

Components of an Electrical Substation

​A substation is part of an electrical power system where voltage is transformed from high to low, or the reverse, using transformers. Substations may also be used for switching purposes, to interconnect sections of a power system, or to isolate parts of it from the rest.

The basic components of a substation are:

-Transformers
-Circuit breakers
-Busbars
-Capacitors
-Isolators
-Lightning arrestors

Transformers are used to change the voltage of an electrical supply. The primary winding of the transformer is connected to the high-voltage supply and the secondary winding is connected to the low-voltage load. The transformer increases or decreases the voltage of the electrical supply according to the ratio of the number of turns on the primary winding to the number of turns on the secondary winding.

Circuit breakers are used to protect electrical equipment from damage caused by overloads or short circuits. They work by breaking the circuit when the current flowing through it exceeds a certain level.

Busbars are used to carry large currents between components in a substation. They are made of copper or aluminum and are usually flat strips with a rectangular cross-section.

Capacitors are used to store electrical energy and to help improve the power factor of an electrical supply. They consist of two metal plates separated by an insulating material called a dielectric.

Isolators are used to disconnect parts of a substation from the rest of the electrical supply. This is done for maintenance or repair work.

Lightning arrestors are used to protect electrical equipment from damage caused by lightning strikes. They work by diverting the lightning strike to the ground where it can be safely discharged.

Functional Design Considerations for Substations

​Functional design considerations for substations are many and varied, but there are some key factors that should be taken into account when designing a substation.

First and foremost, the functional design of a substation must take into account the safety of personnel and equipment. All substation equipment must be properly grounded and bonded to prevent electrical shocks and fires. Access to substation equipment must be limited to authorized personnel only, and all electrical circuits must be properly labeled.

Second, the functional design of a substation must take into account the reliability of power supplies. Substations must be designed to provide a high degree of reliability, meaning that power outages must be kept to a minimum. To this end, substations must be designed with redundancies and backup systems in place.

Third, the functional design of a substation must take into account the efficiency of power distribution. Substations must be designed so that power losses are kept to a minimum. This can be achieved through the use of proper transformer sizing, conductor routing, and other means.

Fourth, the functional design of a substation must take into account the maintenance requirements of the equipment. All substation equipment must be designed for easy maintenance and repair. This includes easy access to all electrical and mechanical components, as well as clear and concise manuals.

Fifth, the functional design of a substation must take into account the costs associated with construction and operation. Substations must be designed to be cost-effective, both in terms of initial construction costs and ongoing operational costs. This includes the use of energy-efficient equipment and materials, as well as careful consideration of long-term costs such as maintenance and repair.

By taking all of these factors into account, it is possible to design a substation that is safe, reliable, efficient, and cost-effective.

Circuit Breakers for Electrical Protection

​Most homes and businesses have circuit breakers as an important part of their electrical system. These devices protect against overloads and shorts, and they're essential for ensuring the safety of your electrical system.

There are different types of circuit breakers, and each has its own advantages and disadvantages. The most common type of circuit breaker is the thermal-magnetic breaker, which uses a thermal element to detect overloads and a magnetic element to detect shorts. These breakers are fast-acting and can be reset easily, but they're not as precise as other types of circuit breakers.

Another type of circuit breaker is the solid-state breaker. These breakers use semiconductor devices to detect overloads and shorts. Solid-state breakers are more precise than thermal-magnetic breakers, but they're not as widely available.

If you're looking for the best protection for your electrical system, you should choose a circuit breaker that's appropriate for the type of system you have. If you have a simple system, a thermal-magnetic breaker may be all you need. But if you have a complex system, you may need a solid-state breaker.

Relays for Automated Operational Control

​Operational control of automated systems is a critical function in many industries. Relays are one of the most commonly used devices for this purpose. A relay is an electrically operated switch that can be used to control circuits with high voltages or currents. When a relay is used to control a circuit, the relay switch is opened or closed by an external voltage or current. This external voltage or current can be generated by a variety of devices, including sensors, timers, and controllers.

Relays are used in a variety of applications, including automotive, industrial, and commercial. In automotive applications, relays are used to control engine timing, lighting, and other electrical functions. Industrial relays are used in a variety of applications, including process control, motor control, and machine safety. Commercial relays are used in security and building automation systems.

Relays can be purchased from a variety of manufacturers. Some of the most popular manufacturers include Omron, Panasonic, and Schneider Electric.

Transformers for Voltage Regulation

​The Transformers are the key component in the Voltage Regulation system. The primary function of a transformer is to transfer electric power from one circuit to another, while at the same time isolating the two circuits. In the case of Voltage Regulation, the transformer serves to maintain a constant voltage level in the system, by either stepping up or stepping down the voltage as necessary.

The basic principle behind transformer action is mutual induction. This is the process whereby an electromotive force is induced in a conductor by a changing magnetic field in the conductor. The changing magnetic field is produced by the flow of current in the primary winding of the transformer. The secondary winding is wound on the same core as the primary, and the changing magnetic field induces a current in the secondary. The changing magnetic field in the primary produces a flux in the secondary, and it is this flux that links the two windings and produces the mutual induction between them.

The primary and secondary windings of a transformer are electrically isolated from each other so that there is no direct electrical connection between them. The only way that power can be transferred between the two windings is by means of the magnetic field. The transformer, therefore, provides a means of transferring power between two circuits without there being any direct electrical connection between them.

The mutual induction between the primary and secondary windings of a transformer is used to transfer electric power from the primary to the secondary. The primary winding is connected to the power supply, and the secondary winding is connected to the load. When current flows in the primary winding, it produces a magnetic field that extends into the secondary winding. This induces a voltage in the secondary winding and current flows in the secondary circuit. The secondary current produces a magnetic field that opposes the field produced by the primary, and this limits the amount of current which can flow in the secondary.

The transformer therefore acts as a voltage regulator, by controlling the amount of current which flows in the secondary circuit. The transformer can be designed to step up or step down the voltage, as required. If the secondary voltage is higher than the primary voltage, the transformer is said to be stepped up. If the secondary voltage is lower than the primary voltage, the transformer is said to be stepped down.

The voltage regulation system comprises a number of transformers connected in series. The first transformer in the series is known as the input transformer, and the last transformer in the series is known as the output transformer. The input transformer steps up the voltage from the power supply to the level required by the system. The output transformer steps down the voltage to the level required by the load.

In between the input and output transformers, there are a number of other transformers, known as tap changers. These are used to maintain the correct voltage in the system by compensating for voltage drops. When the load on the system increases, the tap changers switch to a higher tap, which increases the voltage in the system. When the load on the system decreases, the tap changers switch to a lower tap, which decreases the voltage in the system.

The tap changers are controlled by a voltage regulator, which monitors the voltage in the system and switches the tap changers to the correct position as required. The voltage regulator is usually located at the output of the system so that it can monitor the voltage at the load.

The Voltage Regulation system is a vital part of the electrical power system and ensures that the voltage supplied to the load is kept constant, despite changes in load or power supply.

Busbars for Substation Wiring

​A busbar is an electrical conductor, often made of copper or aluminum, used to carry high currents between different parts of an electrical system. Busbars are used in a wide variety of applications, including substation wiring, switchgear, and battery bank connections.

Busbars can be either bare or insulated. Insulated busbars are used when there is a need to isolate electrical conductors from each other or from the surrounding environment. In substation wiring applications, busbars are often used to connect electrical equipment, such as transformers, circuit breakers, and voltage regulators.

There are a few things to consider when choosing the right busbar for a substation wiring application. The first is the amperage rating of the busbar. The amperage rating is the maximum amount of current that the busbar can safely carry. The second is the voltage rating of the busbar. The voltage rating is the maximum amount of voltage that the busbar can safely handle.

The third and final thing to consider is the material of the busbar. Busbars are typically made of either copper or aluminum. Copper is a more conductive material than aluminum, meaning it can carry more current. However, aluminum is less expensive than copper and is more resistant to corrosion.

When choosing the right busbar for a substation wiring application, it is important to consider the amperage and voltage ratings of the busbar, as well as the material it is made of.

Surge Protectors for Overvoltage Protection

​What are Surge Protectors?
A surge protector is an appliance designed to protect electrical devices from voltage spikes. A surge protector attempts to regulate the voltage supplied to an electrical device by either absorbing or blocking the excess voltage.

How do Surge Protectors Work?
Surge protectors work by connecting an appliance to the electrical device through a conductive metal oxide varistor (MOV). The MOV is designed to have a high impedance until a certain voltage is reached. Once this voltage is reached, the MOV rapidly decreases its impedance, allowing the current to flow through the MOV and into the ground.

Why are Surge Protectors important?
Surge protectors are important because they can help prevent damage to electrical devices from voltage spikes. They can also help prevent fires by absorbing the excess energy from a voltage spike.

How to Choose a Surge Protector?
When choosing a surge protector, it is important to consider the wattage rating, the clamping voltage, the response time, and the let-through voltage. The wattage rating is the maximum amount of power that the surge protector can handle. The clamping voltage is the voltage at which the MOV will start conducting current. The response time is the time it takes for the MOV to start conducting current. The let-through voltage is the voltage that will be allowed to pass through the surge protector after the MOV has started conducting current.

What are the Benefits of Using a Surge Protector?
The benefits of using a surge protector include protection of electrical devices from voltage spikes, prevention of fires, and peace of mind.

Safety Practices for Electrical Substation Installation

​Electrical substations are an integral part of the electrical grid, providing a safe and reliable means of distributing electricity. However, because substations are often located in close proximity to other critical infrastructure, such as gas pipelines and water treatment plants, it is important to follow safety practices to minimize the risk of an accident or explosion.

There are a number of safety practices that should be followed when installing an electrical substation. First, all substation equipment should be properly rated for the voltage and current that it will be handling. Second, all substation equipment should be properly grounded to protect against electrical shock. Third, all substation equipment should be properly bonded to prevent arcing and sparks. Fourth, all substation equipment should be properly ventilated to prevent overheating. Finally, all substation equipment should be regularly inspected and tested to ensure that it is in proper working order.

By following these safety practices, electrical substations can be safely installed and operated, minimizing the risk of accidents or explosions.

Maintenance Requirements for Electrical Substation

​The common checklist of electrical substation maintenance:

General inspection and cleaning of mechanisms (transformers, motors, circuit breakers, batteries, transmission lines, etc)

Measure equipment condition.

Check oil and insulation liquid levels.

Correct torque settings.

Document asset data and record pressure gauges.

Don't make a mistake in carryout the substation maintenance:

Painting – flaky paint and exposed rust cause corrosion. At best this causes damage and downtime to expensive equipment and at worse, renders the power station inoperable.

Cleaning – Keep lines, mechanisms, fences, and gates clear to prevent deterioration build-up. A clean, well-maintained site also helps deter intruders.

Cut the power – Some critical maintenance tests require temporary shutdown to be planned, avoiding disruptions for customers or budgeting surprises.

Use the correct parts – only use equipment supplied by the Original Equipment Manufacturer (OEM). 

Listen for unusual noises –  Anything out of the ordinary should be captured and recorded. Loud or unexpected noises could be signs of malfunction of circuit breakers, transformers, or power lines.

Call a professional – Invest in a knowledgeable workforce of trained technicians, and encourage knowledge transfer and training to ensure correct maintenance operations.

Advantages of Using an Electrical Substation

​(1) All the equipment is within view and therefore fault location is easier. 

(2) The extension of the installation is easier if required. 

(3) The time required for the erection of such substations is lesser. 

(4) The smaller amount of building materials (steel-concrete) is required.

Substations play a critical role in the power industry. They support the transmission grid in moving power from generation sources to customer load, while electrical utilities use them for system protection, switching capabilities, and more importantly, voltage transformations.