STATCOM
Static synchronous compensator
A voltage-source converter in shunt that injects or absorbs reactive current to support voltage, independent of system voltage.
SLD
Symbols · DVR
Dynamic voltage restorer
A series converter that injects a corrective voltage through a transformer to ride a sensitive load through voltage sags.
In plain English
What does Dynamic voltage restorer mean?
A dynamic voltage restorer is connected in series between the supply and a sensitive load through an injection transformer. When the supply voltage sags, a converter fed from a DC store or from the supply itself injects the missing voltage so the load sees an almost constant voltage, typically for sags lasting up to a few seconds.
A simple example
Single-line diagrams show an injection transformer with its primary in series with the feeder, its secondary connected to a converter, and a DC capacitor or storage element. A bypass switch around the injection transformer allows the device to be taken out of service.
What the drawings help you do
A DVR corrects sags but does not supply the load during a full outage, unlike a UPS. The symbol does not show the maximum sag depth or duration it can correct, which depends on the stored energy and converter rating.
This particular reference
A series converter that injects a corrective voltage through a transformer to ride a sensitive load through voltage sags. A DVR injects series voltage for sags; a STATCOM injects shunt current to support bus voltage.
- DC
- Direct current: electricity flowing in one direction.
- Winding
- A coil of conductor inside an electrical machine or transformer.
- Rating
- A value stating the conditions for which equipment is specified.
Read the source: IEC graphical symbols for diagrams · Bidirectional three-/single-phase AC/DC PFC and inverter application note
SLD · DVR
What it represents
A dynamic voltage restorer is connected in series between the supply and a sensitive load through an injection transformer. When the supply voltage sags, a converter fed from a DC store or from the supply itself injects the missing voltage so the load sees an almost constant voltage, typically for sags lasting up to a few seconds.
Single-line diagrams show an injection transformer with its primary in series with the feeder, its secondary connected to a converter, and a DC capacitor or storage element. A bypass switch around the injection transformer allows the device to be taken out of service.
A DVR corrects sags but does not supply the load during a full outage, unlike a UPS. The symbol does not show the maximum sag depth or duration it can correct, which depends on the stored energy and converter rating.
How to read it
- The series transformer, not a shunt connection, identifies a DVR.
- Check the bypass arrangement for maintenance.
Information to show or reference
- State load rating, sag depth and duration corrected.
- Show injection transformer and bypass.
- Reference energy store.
A distinction that matters
A DVR injects series voltage for sags; a STATCOM injects shunt current to support bus voltage.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
IEC graphical symbols for diagrams
IEC graphical symbol context for transformers and converters.
Bidirectional three-/single-phase AC/DC PFC and inverter application note
Public converter stage 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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