# Battery power conversion system

Canonical URL: https://eloragrid.ai/symbols/battery-power-conversion-system
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: PCS
Drawing use: SLD
Reference families: IEC, IEEE / ANSI, Manufacturer

The bidirectional inverter stage of a battery plant that charges and discharges the DC battery from the AC network.

## In plain English

### What does Battery power conversion system mean?

The power conversion system is the bidirectional converter that sits between the battery DC bus and the AC network in a storage plant. It charges the battery by rectifying AC and discharges it by inverting DC, under the direction of a plant controller that sets active and reactive power or operates in a grid-forming mode.

### A simple example

Drawings show a converter box with both AC and DC marks and a bidirectional energy-flow arrow, a DC breaker or switch on the battery side, and an AC breaker, filter and often a medium-voltage skid transformer on the network side. Several PCS units may share one transformer.

### What the drawings help you do

The symbol does not tell you whether the unit can black-start a dead bus, how much overload it can supply or how it limits fault current. Those features drive protection settings and must be read from the converter specification.

### This particular reference

The bidirectional inverter stage of a battery plant that charges and discharges the DC battery from the AC network. A PCS is a utility or commercial storage converter; an inverter-charger is a smaller low-voltage unit with an integral AC transfer relay.

### 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.

- [Battery energy storage and power conversion](https://www.eaton.com/sg/en-us/products/energy-storage.html)
- [Autodesk IEC-60617 preview: Energy-flow qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-2039C5DD-1C01-4D77-AD97-584052C53D75.htm)


## What it represents

The power conversion system is the bidirectional converter that sits between the battery DC bus and the AC network in a storage plant. It charges the battery by rectifying AC and discharges it by inverting DC, under the direction of a plant controller that sets active and reactive power or operates in a grid-forming mode.
Drawings show a converter box with both AC and DC marks and a bidirectional energy-flow arrow, a DC breaker or switch on the battery side, and an AC breaker, filter and often a medium-voltage skid transformer on the network side. Several PCS units may share one transformer.
The symbol does not tell you whether the unit can black-start a dead bus, how much overload it can supply or how it limits fault current. Those features drive protection settings and must be read from the converter specification.

## How to read it

- Look for the bidirectional energy-flow qualifier to confirm charge and discharge capability.
- Check the transformer and filter on the AC side.

## Information to show or reference

- State kW, kVA and DC voltage window.
- Show DC and AC switching and filters.
- Reference control modes and black-start capability.

## Important distinction

A PCS is a utility or commercial storage converter; an inverter-charger is a smaller low-voltage unit with an integral AC transfer relay.

## Facts

- Energy flow: Bidirectional
- Ratings: kW, kVA and DC voltage window
- Network side: Filter and often a skid transformer
- Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic

## Public references

- [Battery energy storage and power conversion](https://www.eaton.com/sg/en-us/products/energy-storage.html) — Eaton. Public power conversion context for battery storage.
- [Autodesk IEC-60617 preview: Energy-flow qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-2039C5DD-1C01-4D77-AD97-584052C53D75.htm) — Autodesk. Public IEC-context energy-flow qualifier family used for the bidirectional mark.

## 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.