COMB
Photovoltaic string combiner
A string combiner brings identified solar DC circuits together at a defined connection arrangement.
Schematic
Symbols · INV CTR
PV central inverter
A large solar inverter fed from DC combiner boxes, usually paired with its own medium-voltage transformer.
In plain English
What does PV central inverter mean?
A central inverter converts the combined output of many PV strings at a single location. Strings are first paralleled in DC combiner boxes, which feed DC recombiners and then the inverter. Ratings run from several hundred kilowatts to several megawatts, and the inverter usually sits in a skid with a medium-voltage step-up transformer and switchgear.
A simple example
Single-line diagrams show the DC combiner network converging on one inverter block, the inverter output to a low-voltage winding of the skid transformer, and the medium-voltage ring main unit. Dual inverters sharing one three-winding transformer are also common.
What the drawings help you do
A central inverter fault takes a large part of the plant offline, and the DC cabling distances are long. The symbol does not show DC earthing arrangement or insulation monitoring, which differ between plants and must be stated separately.
This particular reference
A large solar inverter fed from DC combiner boxes, usually paired with its own medium-voltage transformer. A central inverter collects many combined strings; a string inverter connects a few strings directly.
- DC
- Direct current: electricity flowing in one direction.
- Winding
- A coil of conductor inside an electrical machine or transformer.
- Signal
- Electrical information passed between devices, rather than necessarily the main power supply.
Read the source: Photovoltaic technology and inverter functions · Solar string combiner functions
SLD · INV CTR
What it represents
A central inverter converts the combined output of many PV strings at a single location. Strings are first paralleled in DC combiner boxes, which feed DC recombiners and then the inverter. Ratings run from several hundred kilowatts to several megawatts, and the inverter usually sits in a skid with a medium-voltage step-up transformer and switchgear.
Single-line diagrams show the DC combiner network converging on one inverter block, the inverter output to a low-voltage winding of the skid transformer, and the medium-voltage ring main unit. Dual inverters sharing one three-winding transformer are also common.
A central inverter fault takes a large part of the plant offline, and the DC cabling distances are long. The symbol does not show DC earthing arrangement or insulation monitoring, which differ between plants and must be stated separately.
How to read it
- Trace DC combiner and recombiner levels back to the strings.
- Check whether two inverters share one transformer.
Information to show or reference
- State inverter rating and DC voltage range.
- Show combiner hierarchy and skid transformer.
- Reference DC earthing and insulation monitoring.
A distinction that matters
A central inverter collects many combined strings; a string inverter connects a few strings directly.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Photovoltaic technology and inverter functions
Public photovoltaic inverter function context.
Solar string combiner functions
Public solar string combiner function context.
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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