# Gas turbine generator

Canonical URL: https://eloragrid.ai/symbols/gas-turbine-generator
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: GTG
Drawing use: SLD
Reference families: IEC, IEEE / ANSI

A combustion gas turbine coupled to a synchronous generator, often through a gearbox, shown as a generating unit.

## In plain English

### What does Gas turbine generator mean?

A gas turbine generator uses a continuous-combustion turbine to drive a synchronous generator, often through a reduction gearbox for smaller industrial machines. Units range from microturbines of tens of kilowatts with high-speed alternators and inverters, up to large industrial turbines feeding a medium-voltage bus.

### A simple example

The drawing usually shows a turbine glyph, a trapezoid widening in the direction of flow, joined by a shaft line to the generator circle. A generator step-up transformer, generator breaker and neutral earthing equipment follow on the single-line diagram.

### What the drawings help you do

Microturbines with high-speed alternators produce high-frequency output that must pass through a rectifier and inverter, so check whether a converter sits between the machine and the bus. The symbol does not state fuel, start method or ambient derating.

### This particular reference

A combustion gas turbine coupled to a synchronous generator, often through a gearbox, shown as a generating unit. A gas turbine is a continuous-combustion rotating prime mover; a gas engine is reciprocating.

### Terms

- Winding: A coil of conductor inside an electrical machine or transformer.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Rating: A value stating the conditions for which equipment is specified.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/)
- [AutoCAD Electrical: Power station and substation concepts](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-74EF80E8-018D-4A57-88BD-FF973F1B8185.htm)


## What it represents

A gas turbine generator uses a continuous-combustion turbine to drive a synchronous generator, often through a reduction gearbox for smaller industrial machines. Units range from microturbines of tens of kilowatts with high-speed alternators and inverters, up to large industrial turbines feeding a medium-voltage bus.
The drawing usually shows a turbine glyph, a trapezoid widening in the direction of flow, joined by a shaft line to the generator circle. A generator step-up transformer, generator breaker and neutral earthing equipment follow on the single-line diagram.
Microturbines with high-speed alternators produce high-frequency output that must pass through a rectifier and inverter, so check whether a converter sits between the machine and the bus. The symbol does not state fuel, start method or ambient derating.

## How to read it

- A trapezoid on the shaft line indicates the turbine; a gearbox may be drawn as a small box between turbine and generator.
- Look for a converter stage on microturbine packages.

## Information to show or reference

- State ISO rating and site derating.
- Show gearbox, generator breaker and earthing.
- Reference start system and black-start capability.

## Important distinction

A gas turbine is a continuous-combustion rotating prime mover; a gas engine is reciprocating.

## Facts

- Prime mover: Combustion turbine
- Coupling: Direct or through gearbox
- Microturbine variant: High-speed alternator with converter
- Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic

## Public references

- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/) — IEEE Standards Association. Graphic-symbol standards context for machines and prime movers.
- [AutoCAD Electrical: Power station and substation concepts](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-74EF80E8-018D-4A57-88BD-FF973F1B8185.htm) — Autodesk. Public power station representation context.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.