TCR
Thyristor-controlled reactor
A shunt reactor in series with anti-parallel thyristors whose firing angle sets the reactive power absorbed.
SLD / Schematic
Symbols · SVC
Static var compensator
A shunt reactive power compensator built from thyristor-controlled reactors, thyristor-switched capacitors and filters.
In plain English
What does Static var compensator mean?
A static var compensator is a shunt-connected installation that controls voltage by rapidly varying the reactive power it exchanges with the network. Its branches are typically a thyristor-controlled reactor, one or more thyristor-switched capacitors and harmonic filters, all connected to the secondary of a dedicated step-down transformer.
A simple example
Single-line diagrams show the compensator transformer feeding a medium-voltage bus with each branch drawn separately, or a summary block labelled SVC with a variable capacitor-reactor symbol. It is used at transmission substations, at large industrial loads such as arc furnaces and at some renewable connection points.
What the drawings help you do
Because its output is based on switched reactances, available reactive current falls with voltage, so it gives less support during deep voltage dips than a STATCOM. The symbol does not show the control slope, the branch ratings or the harmonic performance.
This particular reference
A shunt reactive power compensator built from thyristor-controlled reactors, thyristor-switched capacitors and filters. An SVC varies switched reactances; a STATCOM uses a voltage-source converter and holds output current better at low voltage.
- Winding
- A coil of conductor inside an electrical machine or transformer.
- Terminal
- An identified point where a conductor connects.
- Signal
- Electrical information passed between devices, rather than necessarily the main power supply.
Read the source: Static Var Compensators (SVC) · IEC graphical symbols for diagrams
SLD · SVC
What it represents
A static var compensator is a shunt-connected installation that controls voltage by rapidly varying the reactive power it exchanges with the network. Its branches are typically a thyristor-controlled reactor, one or more thyristor-switched capacitors and harmonic filters, all connected to the secondary of a dedicated step-down transformer.
Single-line diagrams show the compensator transformer feeding a medium-voltage bus with each branch drawn separately, or a summary block labelled SVC with a variable capacitor-reactor symbol. It is used at transmission substations, at large industrial loads such as arc furnaces and at some renewable connection points.
Because its output is based on switched reactances, available reactive current falls with voltage, so it gives less support during deep voltage dips than a STATCOM. The symbol does not show the control slope, the branch ratings or the harmonic performance.
How to read it
- Read each branch rating to find the inductive and capacitive range.
- Filters in an SVC usually also supply part of the capacitive output.
Information to show or reference
- State capacitive and inductive range in Mvar.
- Show transformer and branches.
- Reference voltage control slope.
A distinction that matters
An SVC varies switched reactances; a STATCOM uses a voltage-source converter and holds output current better at low voltage.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Static Var Compensators (SVC)
Public SVC page describing TCR, TSC and harmonic filter branches.
IEC graphical symbols for diagrams
IEC graphical symbol context for reactors and capacitors.
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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