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Electrical & Electronics Engineering vocabulary · Standards and Documentation

Single-line diagram

Meaning in electrical & electronics engineering, with examples

nounCommon term

In electrical & electronics engineering, single-line diagram means: A simplified drawing of a power system in which one line represents all the conductors of a circuit. It shows sources, transformers, breakers, busbars and loads, and how they are connected.

In Turkish: tek hat şeması, tek hat diyagramı

How it is used

Used in power design, substations, data centres and industrial plants. Often shortened to SLD, and called a one-line diagram in the US. Engineers review the single-line diagram before any design change, and it is the starting point for short-circuit and protection studies.

Example sentences

  1. Check the single-line diagram to see which breaker feeds the chiller.

  2. The single-line diagram shows two transformers feeding the main busbar.

Common collocations

  • one-line diagram
  • update the SLD
  • SLD review
  • as-built drawings
  • schematicA drawing that shows how the components of a circuit are connected, using standard symbols instead of their real shape or position on the board.
  • wiring diagramA drawing that shows the physical connections of an installation or machine: which wire goes to which terminal, with wire numbers, colors and connector pins.
  • substationA facility in the power network where transformers step the voltage up or down, and where circuits are switched and protected with breakers, disconnectors and protection relays.
  • transformerA device that transfers AC power from one winding to another through a shared magnetic core, usually to step the voltage up or down. It does not work with DC.
  • distribution boardAn enclosure that divides an incoming supply into separate circuits, each protected by its own breaker or fuse. In North America it is usually called a panelboard or breaker panel.

More terms: Standards and Documentation

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