# Static synchronous compensator

Canonical URL: https://eloragrid.ai/symbols/statcom
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: STATCOM
Drawing use: SLD
Reference families: IEC, IEEE / ANSI

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.

### Terms

- 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.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [STATCOM: converter-based reactive power compensation](https://www.hitachienergy.com/products-and-solutions/facts/statcom)
- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/)


## 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.

## Important distinction

A STATCOM uses a converter and keeps reactive current at low voltage; an SVC uses switched reactances whose output falls with voltage.

## Facts

- Core element: Voltage-source converter
- DC side: Capacitor
- Response: Milliseconds
- Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic

## Public references

- [STATCOM: converter-based reactive power compensation](https://www.hitachienergy.com/products-and-solutions/facts/statcom) — Hitachi Energy. Public STATCOM page describing converter-based reactive power support.
- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) — IEC. IEC graphical symbol context for converters.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.