Substation transformer bushing connections involve linking high-voltage and low-voltage cables to the transformer's bushings, which serve as insulated passageways for electrical conductors. Proper layout and phasing are critical for safe and efficient operation.

Types of Transformer Bushings

• •High-voltage bushings (HV): Connect to the incoming power source, typically marked H1, H2, H3
• •Low-voltage bushings (LV): Connect to the outgoing distribution lines, marked X1, X2, X3
• •Neutral bushings: Sometimes present for grounding or neutral return paths

Bushing Layout and Phasing

Layout varies by transformer type:

• •Padmount transformers: Bushings are usually front-facing, with HV on the left and LV on the right
• •Substation transformers: Bushings may be located on the top, sides, or front, depending on the design and enclosure type

Phasing must be consistent between the transformer and connected equipment to avoid faults. Always verify phase sequence before energizing.

Connection Process

• •Inspect bushings for cleanliness and integrity
• •Route cables to the correct bushing terminals, avoiding sharp bends
• •Terminate cables using appropriate lugs and torque specifications
• •Apply insulation kits (heat shrink or cold shrink) to seal connections
• •Ground the transformer via designated grounding bushings or terminals