CFE Transformers
- Grupo Edmar
- 6 days ago
- 7 min read
Updated: 6 hours ago
August 20, 2025 - Electrical Transformers Mexico
CFE Transformers
The Federal Electricity Commission (CFE) plays a crucial role in Mexico's energy infrastructure, ensuring a reliable and secure electricity supply throughout the country. CFE transformers are essential components of this infrastructure, facilitating the efficient distribution of energy throughout the national electricity grid. In this article, we will explore the importance of electrical transformers in the context of their use by the CFE, as well as their impact on Mexico's electricity supply.
What is an Electrical Transformer?
An electrical transformer is an electromagnetic device that modifies the voltage levels of alternating current, transforming electrical energy from one voltage level to another. This process is essential for adapting the energy generated in power plants, which generally operate at high voltages, to the voltage levels required for distribution and consumption in end-user electrical installations.
TYPES OF TRANSFORMERS:
Description: A pad-mounted transformer is a type of transformer mounted on a concrete or metal base, installed in the ground and designed to withstand harsh environmental conditions.
Possible Connections: It can be connected to the street electrical distribution network and to the consumer's electrical installation.
Capacities: Capacities can vary from a few kVA to several hundred kVA, depending on the load requirements of the area to be supplied.
Uses: Commonly used in urban and suburban areas to provide power to residential communities, industrial and commercial parks, and public areas.
Examples: Pedestal transformers are used in residential neighborhoods, ranches, shopping malls etc.
Features: ANCE Certification. Delta-Star connection. Standard type with 65°C overheating. Coastal type (warm climate) with 55°C overheating. 5-position tap changer for output voltage adjustment. Carbon steel tank with corrosion-resistant coating.
Description: A pole transformer is a type of transformer mounted on an electrical pole and designed to be installed outdoors.
Possible Connections: Connects to the street electrical distribution network and to the consumer's electrical installation.
Capacities: Capacities can vary from a few kVA to several hundred kVA, depending on the load requirements of the area to be supplied.
Uses: Commonly used in rural and suburban areas to provide power to dispersed communities and areas where it is impractical to install underground transformers.
Examples: Pole transformers are used in rural and suburban areas to power farms, ranches, and small and large communities.
Features: ANCE certification. Standard type with 65°C overheating. Coastal type (warm climate) with 55°C overheating. Corrosion-resistant tank. Tap changer for outdoor operation.
Description: A dry-type transformer is a type of transformer that uses air or gas as a cooling medium instead of oil, making it safe for indoor use.
Possible Connections: It can be connected to the electrical distribution network or used as an isolation transformer in industrial and commercial systems.
Capacities: Capacities can vary from a few kVA to several MVA, depending on the specific application.
Uses: Used in commercial buildings, hospitals, schools, factories and other facilities where the presence of oil could pose a safety risk.
Examples: Dry-type transformers are used in emergency power supply systems in hospitals and in uninterruptible power supplies (UPS) in data centers.
Features: Primary Voltage (V): 12, 24, 48, 55, 110, 120, 220, 240, 440, 480, 575 V, etc. Secondary Voltage (V): 12, 24, 48, 5 5, 110, 120, 220, 240, 440, 480, 575 V, etc. Primary Connection: Single-phase transformers: Single-phase connection for 2 wires. Three-phase transformers: Delta or star connection. Secondary Connection: Single-phase transformers: Parallel or Series of 3 wires. Three-phase transformers: Delta or star connection.
Substation Type Transformer:
Description: A substation electrical transformer is a type of transformer used in electrical substations to step up or down voltage levels between the transmission grid and the distribution grid.
Possible Connections: Connects the high voltage transmission network with the low voltage distribution network.
Capacities: Capacities can vary from a few MVA to several MVA, depending on the substation capacity and load requirements.
Uses: It is used in electrical substations to interconnect transmission and distribution systems and ensure the stability and reliability of the electrical system.
Examples: Substation transformers are used in large industrial facilities, wind farms, power plants, and other high-power consumption sites.
Features: They can operate at 2 different capacities, depending on the type of cooling selected (OA or FA). They include ANCE certification according to current NMX-J-116 standards. Connection versatility Capacity (KVA): 225, 300, 500, 750, 1000, 1250, 1500, 2000, 2500, 3000, etc. Primary Voltage (V): 4160, 13200, 13800, 22860, 23000, 33000, 34500, etc. Secondary Voltage (V): 220/127, 440/254, 460/266, 480/277, 4160/2402, etc.
Types of Transformers Used by the CFE
The CFE uses a variety of electrical transformers for different applications in its distribution network. These include distribution transformers, power transformers, instrumentation transformers, as well as autotransformers and current and voltage transformers. Each type of transformer performs a specific function in the CFE's electrical grid, from voltage reduction at substations to power distribution to end consumers.
Role of Transformers in Power Distribution: Electrical transformers play a crucial role in the distribution of electrical power throughout the country. They act as "control centers" that regulate and manage the flow of electricity throughout the electrical grid, ensuring that energy is delivered efficiently and safely to end users. Without transformers, electrical power distribution would be much more complex and less efficient.
Impact on the Stability of the Electrical System: The presence of electrical transformers in the CFE distribution network contributes significantly to the stability and reliability of the national electrical system. By allowing the regulation of voltages and currents, transformers help prevent unwanted fluctuations in the grid, thus minimizing the risk of power supply interruptions. This is especially important in a country like Mexico, where the demand for electrical energy can vary significantly across regions and times of day.
What regulations apply to electrical transformers in Mexico?
The transformer standards for the Federal Electricity Commission (CFE) in Mexico are essential to ensuring the safety, efficiency, and reliability of the electrical equipment used in its distribution network. These standards establish the technical and quality requirements that electrical transformers must meet to be used by the CFE. Here is a description of some of the most relevant standards:
NOM-002-SEDE: This standard establishes the safety specifications that low-voltage electrical systems in Mexico must meet. It regulates aspects such as protection against overloads, short circuits, ground faults, and others, in order to guarantee the safety of people and the integrity of electrical installations.
NMX-J-116-ANCE: This standard establishes the requirements and testing methods for oil-filled distribution transformers. It defines technical aspects such as nominal capacity, operating voltage, efficiency, losses, insulation testing, among others, to ensure transformer performance and safety.
NMX-J-123-ANCE: This standard specifies the requirements and test methods for dry-type distribution transformers. It defines technical parameters such as rated capacity, operating voltage, efficiency, losses, insulation testing, and others, to ensure the quality and performance of dry-type transformers.
NMX-J-169-ANCE: This standard establishes the requirements and test methods for submersible power transformers. It defines technical aspects such as rated capacity, operating voltage, efficiency, losses, insulation testing, among others, to ensure the safety and efficiency of submersible transformers.
NRF-002-CFE: This standard establishes the technical and quality criteria that electrical transformers must meet to be accepted by the Federal Electricity Commission (CFE) in Mexico. It defines requirements related to capacity, efficiency, reliability, safety, testing, inspections, among others, to ensure the proper functioning of transformers in the CFE distribution network.
NRF-025-CFE: This standard establishes the technical and quality requirements that electrical metering equipment used by the Federal Electricity Commission (CFE) in Mexico must meet. It defines criteria related to accuracy, reliability, safety, installation, maintenance, testing, and other requirements to ensure proper metering and billing of electrical energy.
LFC-GDD-174: This standard establishes the technical and safety requirements that must be met by the electric power distribution equipment used by the Federal Electricity Commission (CFE) in Mexico. It defines criteria related to the design, construction, operation, maintenance, testing, inspections, among others, to ensure the safety and reliability of distribution equipment in the CFE's electrical grid.
When the transformer is to be transferred to CFE, it must comply with NRF-025-CFE standards.
What is the K standard that CFE requests?
The "K standard" in the context of Mexico's Federal Electricity Commission (CFE) refers to a set of standards and technical specifications that electrical equipment must meet to be accepted by the CFE and used in its distribution network.
The technical criteria included in the "K standard" may vary depending on the type of electrical equipment and the specific needs of the CFE distribution network. Some of the aspects typically considered within the "K standard" include:
Load Capacity: Electrical equipment must be capable of handling the expected energy loads according to the demands of the CFE distribution network.
Energy Efficiency: Minimum energy efficiency requirements can be established for equipment such as transformers, electric motors, lighting, among others.
Electrical Safety: Electrical equipment must comply with established safety standards to prevent electrical accidents and ensure the protection of personnel and infrastructure.
Electromagnetic Compatibility: Electrical equipment must be compatible with the electromagnetic environment of the CFE distribution network to avoid interference and operational problems.
Quality and Durability: Quality and durability requirements can be established to ensure the reliability and lifespan of electrical equipment under real-life operating conditions.
It is important to note that the specific details of the K standard may vary and are subject to change over time, as the CFE continues to update and revise its requirements based on the evolving needs of its electrical infrastructure and available technologies. Electrical equipment manufacturers and suppliers typically work closely with the CFE to ensure their products meet the K standard requirements and can be accepted for use on Mexico's electrical distribution grid.
In conclusion, electrical transformers play a fundamental role in Mexico's energy infrastructure, especially in the context of their use by the Federal Electricity Commission (CFE). From their ability to regulate voltage to their contribution to the stability of the electrical system, CFE transformers are essential elements that guarantee a reliable and secure electricity supply throughout the country. As an integral part of the CFE's distribution network, electrical transformers continue to drive the development and growth of Mexico's energy infrastructure into the future.
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