Components of a Padmount Transformer - Part 2 Secondary compartment

February 16, 2024

This article will go over the components found inside a Padmount Transformer compartment. Part 1 we went over the components on the Primary section of the Padmount Transformer compartment and Part 2 will go over the components that make up the Secondary section.

Components of a Padmount Transformer Compartments Diagram
Components of a Padmount Transformer Compartments Diagram

Vacuum Pressure Gauge: A Vacuum Pressure Gauge in a pad-mount transformer plays a crucial role in monitoring the internal pressure levels, ensuring the transformer operates within safe vacuum conditions. It helps detect any pressure changes that could indicate leaks or other issues affecting the transformer’s performance.

Pressure Relief Valve: is a safety device designed to release excess pressure from the transformer’s tank, preventing potential damage from overpressure conditions. It automatically opens at set pressure levels allowing it to effectively manage pressure surges.

Hand Air Valve: This is used for manually releasing air or adjusting pressure inside the transformer. It is crucial to use the hand valve to release air pressure before removing the bayonet fuses to prevent the ejection of hot oil.

Nameplate: The Nameplate provides critical information about the transformer. It includes details such as the transformer type, phase number, kilovolt ampere rating, serial number, impedance percentage at 85°C, liquid insulant and volume, basic impulse level (BIL), total mass, rated voltages, and PCB content. This nameplate remains legible throughout the transformer’s life under normal use, offering key data for operation, maintenance, and safety purposes.

Low Voltage Terminal Supports: are designed to securely hold the low-voltage terminals in place. These supports ensure that the terminals, which connect the transformer to the distribution network, remain stable and correctly aligned, thereby preventing misconnections, and facilitating safe and efficient power distribution.

Oil Level Gauge: in pad-mounted transformers is a vital component that allows for the monitoring of the oil level within the transformer. This magnetic-type liquid-level indicator is designed to ensure that the insulating oil, crucial for cooling and insulation, is maintained at the appropriate level for optimal operation.

Oil Thermometer: The oil thermometer measures temperature of the transformer’s insulating oil and internal components. It ensures the transformer operates within safe temperature ranges, preventing overheating that could lead to insulation damage, decreased efficiency, or catastrophic failure. By providing real-time temperature readings, it helps in the early detection of thermal anomalies and facilitates timely maintenance interventions.

Low Voltage Spade Connections: These serve as serves as the connection point for the secondary side of the transformer, where the transformed, lower voltage electricity is outputted and distributed to various networks or buildings.

XO Connection to Ground Bus: This connection involves linking the transformer’s neutral point, designated as “XO,” directly to the ground bus. This ensures that any fault currents or electrical surges can be safely directed to the ground, reducing the risk of electrical shock and protecting the transformer from damage due to overvoltages. The connection aids in stabilizing the voltage levels at the transformer’s low-voltage side and provides a clear path for fault currents, contributing to the overall safety and reliability of the electrical distribution system.

Ground Bus: The Ground Bus provides a central point for all grounding connections, enhancing safety and protecting equipment by ensuring effective grounding, stabilizing the electrical system, and preventing voltage surges.

Grounding Terminals: These provide connection points for grounding the transformer, ensuring it remains at earth potential and safeguarding both equipment and personnel from electrical faults. These terminals facilitate the dissipation of fault currents and help maintain the stability of the power system by preventing ground potential rise during fault conditions.

Oil Drain Valve: allows for safe and efficient removal of insulating oil from the transformer for maintenance, testing, or replacement purposes. The valve ensures that oil can be drained without contaminating the environment and without the need to disassemble the transformer.

There are other non-standard components of a pad-mounted transformer that are used depending on the requirements of the end-user and the application. We will discuss these in a future article.