SVC
Static var compensator
A shunt reactive power compensator built from thyristor-controlled reactors, thyristor-switched capacitors and filters.
SLD
Symbols · STATCOM
Static synchronous compensator
A voltage-source converter in shunt that injects or absorbs reactive current to support voltage, independent of system voltage.
In plain English
What does Static synchronous compensator mean?
A static synchronous compensator is a voltage-source converter connected in shunt through a reactor or transformer. By controlling the magnitude of its AC output voltage relative to the network, it supplies or absorbs reactive current. It responds within milliseconds and can maintain close to rated current even when network voltage is low.
A simple example
Drawings show a converter block with a DC capacitor on its DC side, a coupling reactor or transformer, and the connection breaker. Distribution-scale units serving microgrids, wind farms and industrial plants are often drawn as a single converter block labelled STATCOM.
What the drawings help you do
Many STATCOMs can also act as active filters for flicker and harmonics, or be paired with batteries for active power support. The symbol does not show overload capability or which of these functions are enabled.
This particular reference
A voltage-source converter in shunt that injects or absorbs reactive current to support voltage, independent of system voltage. A STATCOM uses a converter and keeps reactive current at low voltage; an SVC uses switched reactances whose output falls with voltage.
- DC
- Direct current: electricity flowing in one direction.
- AC
- Alternating current: electricity whose direction changes periodically.
- Winding
- A coil of conductor inside an electrical machine or transformer.
Read the source: STATCOM: converter-based reactive power compensation · IEC graphical symbols for diagrams
SLD · STATCOM
What it represents
A static synchronous compensator is a voltage-source converter connected in shunt through a reactor or transformer. By controlling the magnitude of its AC output voltage relative to the network, it supplies or absorbs reactive current. It responds within milliseconds and can maintain close to rated current even when network voltage is low.
Drawings show a converter block with a DC capacitor on its DC side, a coupling reactor or transformer, and the connection breaker. Distribution-scale units serving microgrids, wind farms and industrial plants are often drawn as a single converter block labelled STATCOM.
Many STATCOMs can also act as active filters for flicker and harmonics, or be paired with batteries for active power support. The symbol does not show overload capability or which of these functions are enabled.
How to read it
- A DC capacitor rather than a battery on the DC side marks a pure reactive compensator.
- Check whether a battery is shown, which would add active power capability.
Information to show or reference
- State Mvar range and response time.
- Show coupling reactor or transformer.
- Reference control functions enabled.
A distinction that matters
A STATCOM uses a converter and keeps reactive current at low voltage; an SVC uses switched reactances whose output falls with voltage.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
STATCOM: converter-based reactive power compensation
Public STATCOM page describing converter-based reactive power support.
IEC graphical symbols for diagrams
IEC graphical symbol context for converters.
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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