Transformers and substations are critical components of the electrical power system. They are responsible for the safe and reliable transmission and distribution of electricity.
Transformers play a vital role in the power grid, from stepping up voltage for long-distance transmission to stepping down voltage for local distribution.
Substations, on the other hand, are the nodes that connect different parts of the power system, providing the necessary infrastructure for the transformation, switching, and protection of electrical power.
In this blog, we will delve deeper into the world of transformers and substations, exploring how they work, the standards and regulations that govern them, and how they are maintained.
By the end of this blog, you will better understand the critical role transformers and substations play in the electrical power system. So, let’s dive in!
What Is a Power Transformer?
To get started, we should explain what a power transformer is: an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction. Power transformers are typically used to change the voltage level of an alternating current (AC) power supply. The transformer is made up of two or more coils of wire that are wound around a magnetic core.
When an AC voltage is applied to one coil (otherwise known as the primary coil), it creates a magnetic field that induces a voltage in the other coil, called the secondary coil. The ratio of the number of turns in the primary coil to the number of turns in the secondary coil determines the voltage transformation ratio.
Power transformers are used in a wide range of applications, including power generation, transmission, and distribution, in industrial and commercial settings. Pad-mounted transformers, pole-mounted transformers, and substation transformers are the most popular kinds of transformers.
What Is a Substation?
Of course, the title of this blog talks about a power transformer in a substation. So, what exactly is a substation?
A substation is part of an electrical generation, transmission, and distribution system used to transform voltage levels, regulate power flow, and switch circuits. It is a facility that connects power generators, transmission lines, and distribution lines to supply power to homes, businesses, and other consumers.
Substations are typically located near power plants or along transmission lines and are designed to protect equipment and maintain a stable power supply. They also provide a point where power can be switched from one circuit to another and where voltage can be stepped up or down depending on the requirements of the electrical grid system.
Substations can vary in size and complexity, from small distribution substations that serve local communities to large transmission substations that serve entire regions.
The Function of a Power Transformer in a Substation
A power transformer in a substation changes the voltage level of the electrical power being transmitted from the power plant to the distribution system or from the distribution system to the end users. Power transformers are designed to step up or step down the voltage levels of the electrical power depending on the requirements of the electrical grid system.
The generator produces electrical power at a low voltage level at the power plant, typically 10 kV to 30 kV. This voltage is then stepped up to a higher voltage, typically 220 kV to 765 kV, by a power transformer before it is transmitted over long distances through transmission lines. This high voltage is necessary to reduce the power losses that occur during transmission.
At the substation, the high-voltage power is stepped down to a lower voltage level, typically 35 kV to 15 kV, by another power transformer before it is distributed to the local distribution system. The distribution system is responsible for delivering the power to homes, businesses, and other consumers at a voltage level that is safe and appropriate for their use, typically 5 kV to 240/120 V.
The power transformer plays a crucial role in the electrical grid system by enabling the efficient transmission and distribution of electrical power over long distances while ensuring that the voltage levels are appropriate for the end users.
For how powerful substation transformers are, it’s important to have standards and regulations to ensure they function properly and do their job without causing harm. Now that we know how power transformers work in a substation, let’s look at how they’re kept up and running for safe electrical power distribution.
Transformer Standards and Regulations
Transformers are critical components of the electrical power system, and several standards and regulations govern their design, construction, and operation.
The Institute of Electrical and Electronics Engineers, the International Electrotechnical Commission, the National Electrical Manufacturers Association, and the National Electrical Code all govern how power transformers must be maintained for safe, correct use.
- IEEE Standards: The Institute of Electrical and Electronics Engineers (IEEE) has developed several standards related to transformers, including IEEE C57.12.00, which provides general requirements for liquid-immersed distribution, power, and regulation transformers, and IEEE C57.12.90, which provides specific requirements for dry-type transformers.
- IEC Standards: The International Electrotechnical Commission (IEC) has developed several standards related to transformers, including IEC 60076, which provides general requirements for power transformers, and IEC 60076-11, which provides specific requirements for dry-type transformers.
- NEMA Standards: The National Electrical Manufacturers Association (NEMA) has developed several standards related to transformers, including NEMA TR 1, which provides general requirements for transformers, and NEMA ST 20, which provides specific requirements for dry-type transformers.
- Regulatory Agencies: In addition to standards organizations, several regulatory agencies govern the design, construction, and operation of transformers.
For example, the U.S. Environmental Protection Agency (EPA) regulates the use of polychlorinated biphenyls (PCBs) in transformers, and the Occupational Safety and Health Administration (OSHA) regulates the safety of workers who operate and maintain transformers. - National Codes: Many countries have national codes that govern transformers’ design, construction, and operation. For example, the National Electrical Code (NEC) in the United States provides requirements for installing and maintaining transformers.
As you can see, transformers are subject to several standards and regulations that govern their design, construction, and operation. Compliance with these standards and regulations is essential to ensure the transformers’ safe and reliable operation in the electrical power system.
How Power Transformers Are Maintained
Just like standards and regulations matter, so does the day-to-day operation of power transformers. This typically involves maintenance to ensure everything runs as smoothly as possible. Here are some of the maintenance procedures that are typically performed on power transformers in substations:
- Visual Inspection: A visual inspection is performed to check for any signs of damage or corrosion on the transformer’s exterior. This includes checking for oil leaks, rust, or damage to the bushings, tap changers, or cooling system.
- Oil Sampling and Analysis: Transformer oil is analyzed to determine its condition. The analysis can reveal the presence of contaminants, moisture, or other impurities that can affect the transformer’s performance. The oil is also tested for its dielectric strength, acidity, and viscosity.
- Electrical Testing: Electrical testing is performed to check the transformer’s insulation resistance, winding resistance, and turns ratio. These tests can help detect any signs of insulation breakdown or winding faults.
- Cooling System Maintenance: The cooling system, which includes fans, radiators, or heat exchangers, is inspected and cleaned to ensure that it is functioning properly. Any blockages or obstructions are removed to ensure proper cooling.
- Tap Changer Maintenance: Tap changers are inspected and tested to ensure they function properly. Any signs of wear or damage are addressed, and the contacts are cleaned and lubricated.
- Bushing Maintenance: Bushings provide the electrical connection between the transformer and the outside world and are inspected and tested to ensure they function properly. Any signs of damage or wear are addressed, and the bushings are cleaned and lubricated.
- Transformer Overhaul: In some cases, a transformer may need to be overhauled to replace worn or damaged components. This may involve replacing the winding, core, or insulation, or repairing any damage to the tank or other components.
By performing these maintenance procedures regularly, power transformers can be kept in good working condition, and their lifespan can be extended. It is important to follow the manufacturer’s guidelines and industry standards when performing maintenance on power transformers to ensure their safe and reliable operation.
Transformer Testing
In addition to regular maintenance, testing the transformers to ensure they are working properly and safely is very important. Routine, type, and special tests are the most commonly performed tests.
Routine Tests
Routine tests are performed on every transformer to ensure it meets the specified requirements. These tests include the measurement of winding resistance, measurement of voltage ratio and vector relationship, measurement of impedance voltage, and measurement of no-load loss and current.
These tests verify that the transformer has been manufactured according to the design specifications and that it is ready for installation in the power system.
Type Tests
Type tests are performed on a sample transformer to verify that it meets the requirements of the relevant standards.
Type tests include the measurement of power frequency voltage withstand, measurement of lightning impulse voltage withstand, measurement of sound level, measurement of temperature rise, and measurement of short-circuit withstand.
The purpose of these tests is to verify that the transformer will perform safely and reliably under extreme conditions.
Special Tests
Special tests are performed on transformers with unique design features or those intended for special applications. These tests may include measurement of partial discharge, measurement of harmonic distortion, measurement of zero-sequence impedance, and measurement of transient response. The purpose of these tests is to verify that the transformer will perform as intended in the specific application.
Continual testing and maintenance ensure that substation power transformers work the way they’re supposed to so power can be properly distributed.
Let UTB Transformers Fill All Your Transformer Needs
Transformers and substations are critical components of the electrical power system, and their proper design, construction, and maintenance are essential to ensure the safe and reliable operation of the power grid.
UTB Transformers is a leading provider of high-quality transformers and substations, with a proven track record of delivering customized solutions to meet the unique needs of our customers.
Whether you need a transformer or substation for a new project or an upgrade to an existing system, UTB Transformers has the expertise and experience to deliver a solution that meets your requirements. Our team of experts will work with you every step of the way, from initial design to final installation and commissioning, to ensure your project succeeds.
So, if you need a transformer or substation, look no further than UTB Transformers. Contact UTB Transformers today to learn more about our products and services and how we can help you meet your power system needs.
