DG
Diesel generator set
A compression-ignition engine coupled to an alternator, shown as a source on microgrid and standby power single-line diagrams.
SLD
Symbols · GG
Gas engine generator set
A spark-ignited reciprocating engine on natural gas, biogas or LPG driving an alternator, shown as a generating source.
In plain English
What does Gas engine generator set mean?
A gas engine generator set uses a spark-ignited reciprocating engine running on natural gas, biogas, landfill gas or LPG. These sets are common in combined heat and power plants, prime power microgrids and sites with a reliable gas supply, and they are often run continuously rather than only as backup.
A simple example
Single-line diagrams draw the alternator circle with an engine block marked G or GAS, the generator breaker, and sometimes heat recovery references. When several sets run in parallel, a common synchronising bus and a load-sharing controller appear alongside.
What the drawings help you do
Gas engines usually accept large load steps less readily than diesel engines, which affects how a microgrid sequences load after a blackout. The symbol does not express block-load acceptance, gas pressure requirements or emissions limits.
This particular reference
A spark-ignited reciprocating engine on natural gas, biogas or LPG driving an alternator, shown as a generating source. A gas engine set uses spark ignition and gaseous fuel; a gas turbine generator uses a continuous-combustion turbine.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: Generator switchgear and paralleling controls · Reliable hybrid power and microgrid solutions
SLD · GG
What it represents
A gas engine generator set uses a spark-ignited reciprocating engine running on natural gas, biogas, landfill gas or LPG. These sets are common in combined heat and power plants, prime power microgrids and sites with a reliable gas supply, and they are often run continuously rather than only as backup.
Single-line diagrams draw the alternator circle with an engine block marked G or GAS, the generator breaker, and sometimes heat recovery references. When several sets run in parallel, a common synchronising bus and a load-sharing controller appear alongside.
Gas engines usually accept large load steps less readily than diesel engines, which affects how a microgrid sequences load after a blackout. The symbol does not express block-load acceptance, gas pressure requirements or emissions limits.
How to read it
- Check the load-step limits in the controller documents before assuming the set can pick up a whole bus at once.
- Heat recovery or CHP notes indicate continuous running.
Information to show or reference
- State fuel type and rating basis.
- Show breaker and synchronising arrangement.
- Reference load acceptance and start sequence.
A distinction that matters
A gas engine set uses spark ignition and gaseous fuel; a gas turbine generator uses a continuous-combustion turbine.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Generator switchgear and paralleling controls
Public generator paralleling and switchgear context.
Reliable hybrid power and microgrid solutions
Public hybrid microgrid context combining gensets, solar, storage and mains.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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Synchronism check
Checks documented synchronising conditions before a permitted connection.
Protection functions
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