Power Transformer Simulator

Model a power transformer from 25 kVA to 10 MVA — adjust loading, impedance, power factor, tap position, and ambient temperature, then explore efficiency curves, thermal loading, voltage regulation, and fault behavior.

AVAILABLEAUTOMATED CHECKS ONLYSTANDARDS-AWAREINTERMEDIATEIEEENETA ATSWHAT DO THESE STATUSES MEAN?

25 kVA – 10 MVAEFFICIENCY CURVETHERMAL MODELTAP CHANGER

Launch lab Sign in to bookmark Report an issue with this lab Try a guided scenario

Overview

Power transformers sit at the center of every distribution system, and their behavior under varying load, ambient temperature, tap position, and fault conditions directly affects system reliability, efficiency, and protection coordination. This simulator builds an interactive transformer model: enter nameplate kVA (25 kVA–10 MVA), percentage impedance, no-load and full-load losses, then adjust load percentage, power factor, tap position, and ambient temperature to see secondary voltage, efficiency, losses, and thermal loading update in real time. The Loading tab plots efficiency vs. load curve and a loss breakdown (core losses vs. copper losses). The Thermal tab models temperature rise under sustained and overload conditions, including ONAN base rating versus active cooling stage. The Fault tab explores through-fault current magnitude and short-circuit withstand. A Scenarios tab provides preset transformer configurations from small dry-type distribution units to large liquid-filled substation transformers. A Quiz tab reinforces transformer theory. Secondary voltage options span 208 V through 23,000 V; primary voltage from 208 V through 69 kV.

App preview

A live look at the app you'll launch — every control on the left drives the visualizations on the right in real time.

Inside the lab

Example data — not a real field report

Transformer dashboard with loading gauge and nameplate — Dashboard — transformer diagram, loading gauge, nameplate data, secondary voltage, and an event log give an at-a-glance operational snapshot.

Efficiency vs load curve and loss breakdown — Loading & Losses — efficiency vs. loading curve, core-vs-copper loss breakdown, and voltage regulation vs. load show where the unit peaks and why.

Thermal loading and cooling stage model — Thermal — temperature rise model tracks top-oil and winding temperatures across ONAN base rating and active cooling stages under sustained and overload conditions.

Through-fault current and inrush — Fault / Inrush — through-fault current magnitude, short-circuit withstand, and inrush multiplier tie transformer impedance directly to protection coordination.

Preset transformer scenarios — Scenarios — one-click presets from small dry-type distribution units to large liquid-filled substation transformers make it easy to compare designs.

Transformer theory quiz — Quiz — reinforce transformer theory with a focused knowledge check on losses, regulation, taps, and thermal behavior.

Learn tab covering transformer theory — Learn — loss theory, tap changer operation, thermal model, and regulation math tie the interactive tabs back to the underlying equations.

What you'll do

01Explain the two components of transformer losses — core (no-load) losses and copper (load) losses — and identify at what load level efficiency is maximized
02Calculate voltage regulation for a transformer at given impedance, load, and power factor
03Explain how tap changer position affects secondary voltage and when DETC versus OLTC are used
04Describe transformer thermal loading and explain why the ONAN rating is the most conservative nameplate value
05Calculate through-fault current magnitude using transformer impedance and explain its role in protection coordination
06Predict the effect of ambient temperature on transformer loading capacity and top-oil temperature rise

Try a guided scenario

Load a transformer and observe how ratio, impedance, and loading interact.

Transformer fundamentals · Electrical Foundations

No sign-in required. Progress is saved on this device.

What this lab is not

Not a design document, stamped calculation, or approval record.
Not a substitute for engineering analysis by a licensed professional.
Not an accredited test report — it is a NETA-aligned educational field workflow, and acceptance decisions stay with the responsible test organization.
Not connected to live equipment and not a safety device.

Calculation basis

References IEEE, NETA ATS. Results are computed from the entered inputs and cited back to the referencing clause or table number — no code text or table is reproduced verbatim.

Simplifying assumptions are stated in the lab itself; where a model is intentionally conceptual, the lab says so rather than implying study-grade accuracy.

Standards basis: Standards-aware. Validation state: Automated checks only (last checked 2026-08-15).