The power topology of your distribution system.
Turn your equipment and cable schedule into an editable single line diagram. Import an .xlsx or .csv, check the topology it builds, adjust it on the sheet, and export PDF, PNG, SVG or a workbook.
Free while it is early. No account, nothing uploaded.
From schedule to single line
Reduce drafting from days to hours. Import the schedule you already keep and the studio draws the diagram from it. When the schedule changes, merge the new one into the same drawing instead of redrawing it.
| Asset Tag | Type | Rating | Voltage | Level |
|---|---|---|---|---|
| GEN-A | Generator | 2000 kW | 11 kV | 1 |
| GEN-B | Generator | 2000 kW | 11 kV | 1 |
| INC-A | Utility Source | 4000 kVA | 11 kV | 1 |
| INC-B | Utility Source | 4000 kVA | 11 kV | 1 |
| RMU-A | RMU | 630 A | 11 kV | 2 |
| RMU-B | RMU | 630 A | 11 kV | 2 |
| TX-A | Transformer | 2500 kVA | 11 kV / 400 V | 3 |
| TX-B | Transformer | 2500 kVA | 11 kV / 400 V | 3 |
| MSB-A | Switchgear | 4000 A | 400 V | 4 |
| MSB-B | Switchgear | 4000 A | 400 V | 4 |
| CH-A | Chiller | 400 kW | 400 V | 5 |
| CH-B | Chiller | 400 kW | 400 V | 5 |
| EF-A | Exhaust Fan | 15 kW | 400 V | 5 |
| EF-B | Exhaust Fan | 15 kW | 400 V | 5 |
| UPS-A | UPS | 1250 kVA | 400 V | 6 |
| UPS-B | UPS | 1250 kVA | 400 V | 6 |
| BAT-A | Batteries | 600 kW | 480 V DC | 6 |
| BAT-B | Batteries | 600 kW | 480 V DC | 6 |
| RACK-01 | Telecom Rack | 150 kW | 400 V | 7 |
| RACK-02 | Telecom Rack | 150 kW | 400 V | 7 |
| RACK-03 | Telecom Rack | 150 kW | 400 V | 7 |
| RACK-04 | Telecom Rack | 150 kW | 400 V | 7 |
| From | To | Supply | Protection | Breaker | Cable |
|---|---|---|---|---|---|
| INC-A | RMU-A | 1st source | VCB | 250 A | 3c x 185 mm² XLPE |
| INC-B | RMU-B | 2nd source | VCB | 250 A | 3c x 185 mm² XLPE |
| GEN-A | RMU-A | Emergency / standby | VCB | 250 A | 3c x 185 mm² XLPE |
| GEN-B | RMU-B | Emergency / standby | VCB | 250 A | 3c x 185 mm² XLPE |
| RMU-A | RMU-B | — | Bus tie | 250 A | 3c x 185 mm² XLPE |
| RMU-A | TX-A | 1st source | VCB | 250 A | 3c x 95 mm² XLPE |
| RMU-B | TX-B | 2nd source | VCB | 250 A | 3c x 95 mm² XLPE |
| TX-A | MSB-A | 1st source | ACB | 4000 A | Busduct 4000 A |
| TX-B | MSB-B | 2nd source | ACB | 4000 A | Busduct 4000 A |
| MSB-A | MSB-B | — | Bus tie | 4000 A | Busduct 4000 A |
| MSB-A | CH-A | 1st source | MCCB | 800 A | 2 × 4c x 300 mm² XLPE |
| MSB-B | CH-B | 2nd source | MCCB | 800 A | 2 × 4c x 300 mm² XLPE |
| MSB-A | EF-A | 1st source | MCB | 63 A | 4c x 25 mm² XLPE |
| MSB-B | EF-B | 2nd source | MCB | 63 A | 4c x 25 mm² XLPE |
| MSB-A | UPS-A | 1st source | ACB | 1600 A | 4 × 4c x 400 mm² XLPE |
| MSB-B | UPS-B | 2nd source | ACB | 1600 A | 4 × 4c x 400 mm² XLPE |
| BAT-A | UPS-A | Emergency / standby | Fuse | 1250 A | DC 8 × 1c x 300 mm² |
| BAT-B | UPS-B | Emergency / standby | Fuse | 1250 A | DC 8 × 1c x 300 mm² |
| UPS-A | RACK-01 | 1st source | ACB | 400 A | 2 × 4c x 185 mm² XLPE |
| UPS-B | RACK-01 | 2nd source | ACB | 400 A | 2 × 4c x 185 mm² XLPE |
| UPS-A | RACK-02 | 1st source | ACB | 400 A | 2 × 4c x 185 mm² XLPE |
| UPS-B | RACK-02 | 2nd source | ACB | 400 A | 2 × 4c x 185 mm² XLPE |
| UPS-A | RACK-03 | 1st source | ACB | 400 A | 2 × 4c x 185 mm² XLPE |
| UPS-B | RACK-03 | 2nd source | ACB | 400 A | 2 × 4c x 185 mm² XLPE |
| UPS-A | RACK-04 | 1st source | ACB | 400 A | 2 × 4c x 185 mm² XLPE |
| UPS-B | RACK-04 | 2nd source | ACB | 400 A | 2 × 4c x 185 mm² XLPE |
Made up to show the idea: ratings and cable sizes are illustrative, not a design.
The same 22 items, drawn two ways. Drag across the drawing, or use the arrow keys.
- ImportAn .xlsx with an Equipment and a Cable schedule sheet, or a cable schedule alone as .csv. Your own column headings are matched by name; where the studio cannot tell, it asks.
- GenerateItems land on their levels, feeders are routed, and the checks run. Nothing is placed by hand unless you want it there.
- Refine and exportMove, rename, reconnect, annotate. Then PDF, PNG, SVG, or the workbook with the positions in it.
What it does, specifically
Reads your schedules
.xlsx workbooks with Equipment, Cable schedule, Busbars, Tap-offs, Groups and Levels sheets. A .csv cable schedule alone is enough: the From and To tags become the equipment. Project .json files open too, and so do the .svg and .png exports that carry their project. Someone else's headings go through a column mapping step.
Draws the sheet
Levels and rows, busbars with tap-offs, ties and normally-open links, enclosures such as E-houses and skids, cable labels with leaders. Legend and title block go on A-series paper or true size.
Checks the model
No live supply, duplicate tags, items past their rating or above 80 per cent, critical items on one feed, upward feeders, missing ratings, voltage changes with no transformer, feeders with no cable size. Then a source-loss study: remove each source in turn and read what goes dead.
Keeps revisions
An issue register with revision, status from work in progress to as-built, date and note, stamped on the sheet. Title block fields for drawing number, client, drawn, checked and approved. Restore points saved in the browser and as a file. No side-by-side revision comparison yet.
Gets it out
PDF, PNG, SVG, JSON, a project workbook and a cable schedule CSV, for the whole drawing or a selection. SVG and PNG can carry the project, so the picture you send opens again as a drawing.
Shares without a server
One self-contained viewer file that opens in any browser, by download or email, or a picture copied to the clipboard. A revised schedule merges into an existing drawing. There is no live co-editing; shared cloud projects are planned, not built.
- Industrial plant
- Production hall drives
- MV ring main
- N+1 UPS block
- Small factory
- Data hall, 2N
- Commercial building
- Solar and battery site
- Overhead busway
- Rising busbar
What it is, and what it is not
A single line diagram at board level: sources, switchboards, transformers, transfer switches, busbars and their tap-offs, down to distribution boards and panels. It holds the connectivity as a model, so the drawing can answer questions about supply rather than only show lines.
It is not a study package. If you need fault levels, grading curves or an arc flash label, that work happens somewhere else and always will.
- Drawn toBoard and feeder level — not individual breakers, relays or CT circuits
- SymbolsBoxes and glyphs drawn for readability on A3 and A1 sheets. Not an IEC 60617 symbol library, and not a CAD drawing
- VoltageLV and MV distribution, from the incomer down
- RecordsRatings, cable sizes, protection and load kW as data on each item
- Does not doLoad flow, short-circuit, arc flash, protection grading, cable sizing
Your drawings stay yours
It runs entirely in the browser. No server holds your drawing, because no server is involved.
Which cuts both ways, so it is worth saying plainly: the browser copy is a convenience, not a backup. Safari clears a site's local storage after seven days without a visit, and "clear browsing data" removes it in any browser. Save the JSON file. That is the copy that survives a cleared browser, a new laptop and a colleague who needs it.
- The real saveA JSON file you keep, on your own disk
- Working copyThis browser, on this machine — cleared if the browser is
- What is uploadedNothing
- OfflineWorks after the first visit
- AccountNot required
- ExportsSVG, PNG, PDF, XLSX, CSV, JSON
Free, with Pro planned
No trial, no card, no account.
- No limit on equipment, levels or rows
- Schedule import, drawing and the electrical checks
- Export to PDF, PNG, SVG, JSON and the workbook
- Works offline, nothing uploaded
Pro, planned
For engineers who use it every day: energise and de-energise equipment, more sources and feeder colours, equipment colours, power outage simulation, focus, switching off with downstream impact, rapid status assignment, drawing-quality marks, sorting the sheet, exports that reopen as the project, and continuous autosave. Free saves the first time and whenever you press Ctrl + S. These controls are in the studio now, marked Pro. Pro is not on sale yet.
Cloud projects and Team, planned
A place to keep a company project in the cloud: one editor, any number of viewers, then comments, review and shared templates for a team. Not built yet, and nothing you draw now depends on it.
Questions
What is a power topology diagram?
A power topology diagram shows how electrical distribution equipment is connected: which source feeds which board, where the ties are, and what depends on what. It is the connectivity behind a single line diagram, held as a model so the drawing can answer questions about supply.
Can I import a cable schedule?
Yes. Import an .xlsx workbook with an Equipment sheet and a Cable schedule sheet, or a cable schedule on its own as .xlsx or .csv: the tags in the From and To columns become the equipment, and an equipment register adds types, ratings and levels. Your own column headings are matched by name, and the studio asks which column is which when it cannot tell. A template workbook and a sample schedule are available.
What can I export?
PDF (one page per sheet, in any A size or true size), PNG, SVG, the drawing as JSON, the project as an .xlsx workbook with equipment and cable schedules, a cable schedule as CSV, and a one-file viewer that opens in any browser. An exported SVG or PNG can carry the project inside it, so the picture you send can be opened again as a drawing.
What does it check?
Equipment with no live supply, duplicate tags, items loaded past their rating or above 80 per cent, critical items fed from one source only, feeders that run upward, supply items with no rating, feeders that cross a voltage change with no transformer, and feeders with no breaker or cable size. It also runs a source-loss (N-1) study that removes each source in turn and lists what goes dead.
Does it keep revisions?
It keeps an issue register: revision, status (work in progress, for review, for tender, for construction, as-built, superseded), date and note, stamped on the sheet with a title block that carries drawing number, client, project and drawn, checked and approved by. Restore points are kept in the browser and can also be saved as a JSON file, and undo goes back through every edit. It does not yet compare two revisions side by side.
Can several people work on one drawing?
Not at the same time. A drawing can be sent as one self-contained viewer file or as JSON, and a revised schedule can be merged back into an existing drawing. Shared projects kept in the cloud are planned, not built.
Is it free?
The studio is free to use: no trial, no account, and no limit on equipment, levels or rows. Importing a schedule, drawing and editing, the electrical checks and every export are free. Pro is planned and is not on sale yet. It will add energise and de-energise, more sources and feeder colours, equipment colours, power outage simulation, focus, and switching off with its impact. Those controls are marked Pro in the studio. Cloud projects and Team are planned after that.
Does PowerTopology do load flow or short-circuit calculations?
No. PowerTopology draws and models the topology: what feeds what, what is energised, and what is lost when a source goes. It does not calculate load flow, short-circuit levels, arc flash, protection grading or cable sizing, and it does not replace AutoCAD or a study package.
Where are my drawings stored?
In your browser, on your own machine. Nothing is uploaded to a server and the studio works offline. Browsers can clear their stored data, so save the JSON file: that is the copy that survives a cleared browser or a new laptop.