Power Systems
Per-unit base, feeder voltage drop, transformer sizing, LV cable sizing and transformer-bus fault level, ported from PowerSys Pro + psextract.
◈System Base
Per-unit reference shared by fault calculations below.
〜Feeder Voltage Drop
3-phase feeder drop from R/X per km, length, load and PF.
▣Transformer Sizing + Fault Level
Recommended standard size, utilisation and symmetrical/asymmetrical fault current.
🔌LV Cable Sizing IEC 60364
Copper XLPE, derated for installation + ambient, with VD check.
⚠Short-Circuit at Bus
Fault current at transformer LV bus including feeder impedance.
📏Design Standards
Switches formulas, limits and references across the calculators.
📈Live Load Study 0–150%
Drag the slider: feeder VD, transformer loading and cable VD recalculate live from your inputs above. Same slider drives SLD loading colours.
Power Flow (Load Flow)
Newton–Raphson AC load flow on a user-editable network. Edit bus loads/generation and branch impedances, then solve: bus voltages, angles, branch flows and losses are computed, not mocked. Bus type: slack (1, reference), PV (generator, holds V), PQ (load).
Buses - edit V (kV), Type, P (kW), Q (kVar); Vm/angle are solved
| # | Name | V kV | Type | P kW | Q kVar | Vm p.u. | Va ° |
|---|
Branches - R, X in Ω, rating kVA
| From | To | R Ω | X Ω | Rate kVA | P→ kW | Q→ kVar | Load % | Loss kW |
|---|
Motor Starting: Voltage Dip
Locked-rotor inrush and the voltage dip it imposes at the point of common coupling (PCC). Impedance-divider method per IEC 60034-12 / AS-NZS 3000 §3.5. Checks against typical start-dip limits.
ⓂMotor + Supply
Motor nameplate + upstream fault level at the PCC.
📉Start Method Comparison
Same motor started four ways: effective inrush and resulting PCC dip.
| Method | I_start A | Dip % | Status |
|---|
Cable Short-Circuit Withstand
Adiabatic thermal check (IEC 60364-4-43 / BS 7671): a conductor must survive fault energy I²t without exceeding its insulation temperature. Computes minimum area and maximum permissible clearing time.
🔥Adiabatic Check k²S² ≥ I²t
k from material + insulation (BS 7671 Table 43.1).
📋k Factors
Typical conductor k (BS 7671 Table 43.1), for ≤5 s faults.
| Insulation | Cu | Al |
|---|---|---|
| XLPE / EPR (90°C) | 143 | 94 |
| PVC (70°C) | 115 | 76 |
| PVC (90°C) | 100 | 66 |
| Bare conductor | 176 | 116 |
Power Factor Correction
Size a capacitor bank to raise power factor to a target: Q_c = P·(tan φ₁ − tan φ₂). Includes detuning note for harmonic-rich systems.
⚙Capacitor Sizing
Existing load + present/target power factor.
📊What changes
Before vs after correction.
| Quantity | Before | After |
|---|
Arc Flash Hazard IEEE 1584-2018
Incident energy and arc-flash boundary per the IEEE 1584-2018 empirical model (1,800+ tests): arcing current (with reduced-current case), enclosure size correction, and PPE category per NFPA 70E. Safety-critical: verify against your protection study before use.
⚡Arc Flash Calculation
Equipment + fault data. Voltage 208 V–15 kV; G per equipment class.
🦺PPE Category NFPA 70E
PPE category from the highest (reduced-current) incident energy.
| Case | I_arc kA | E cal/cm² | AFB mm | PPE |
|---|
| PPE Cat | Incident energy |
|---|---|
| 0 / none | ≤ 1.2 cal/cm² |
| 1 | ≤ 4 |
| 2 | ≤ 8 |
| 3 | ≤ 25 |
| 4 | ≤ 40 |
Network Analysis Report
psextract-style system report. Edit bus voltages live: compliance re-evaluates instantly. Sample 5-bus demo case preloaded.
Bus Results - click Vm / load cells to edit
| Bus | Name | V (kV) | Vm (p.u.) | Va (°) | P (kW) | Q (kVar) | Status |
|---|
Branch Power Flows
| From | To | Pf (kW) | Qf (kVar) | Loading % | Status |
|---|
Short-Circuit Analysis (Z-bus method, sample)
| Bus | I_sc (kA) | S_sc (MVA) | Z_sc (Ω) | Breaker ≥ |
|---|
NERC Compliance
| Check | Result | Status |
|---|
Generator Dispatch
| Unit | P (kW) | Q (kVar) | Vset (p.u.) | Profile |
|---|
Single-Line Diagram Builder
Click a component on the left to drop it on the canvas: there are no modes to learn. The new symbol is placed for you and, if something is already selected, wired to it automatically, so you can build a feeder by simply clicking Generator → Breaker → Busbar → Transformer → Motor. To connect two things by hand, drag a ● dot onto another symbol: it snaps for you, so you don't need to aim precisely. The canvas is unlimited: pan with Space-drag or middle-drag and zoom out freely, and the grid follows you. Drag a symbol to move it (it snaps to the grid and shows alignment guides against its neighbours), click a breaker to open or close it, double-click a load to change its loading.
Components
Click to add · or drag onto the canvas
Start from a template
Start over
🗺 Draw your single-line diagram
Click a component on the left to drop it here, or start from a ready-made template.
Properties
Live mirror of the diagram above: breakers you open de-energise everything downstream, and load colours follow each load's loading %. Drag to orbit · scroll to zoom · right-drag to pan · click equipment for details.
3D Substation Viewer
The whole substation in 3D: what every tool in this app is actually describing. Grid infeed → gantry → breaker → 11 kV bus → transformer → LV switchgear → capacitor bank → motor + loads, with live loading colours, power-flow particles and the arc-flash zone around the switchgear. Switch the source to SLD diagram and the same viewer rebuilds itself from whatever you drew in the SLD Builder.
True scale for design review: 1 unit = 1 metre, equipment heights match real dimensions (11 kV pylon 12 m · transformer ≈ 2.5 m · worker 1.8 m). Positions are illustrative, not construction drawings. Drag to orbit · scroll to zoom · right-drag to pan · click any equipment for its details.
Substation Map
Live power infrastructure on OpenStreetMap data: transmission and distribution lines coloured by voltage from OpenInfraMap, with substations loaded live from Overpass as you pan and zoom. Zoom in to level 11 or closer to load live substation markers for the area on screen.
Map loads when this section scrolls into view. Zoom in to load live substation data.
Engineering Report
Collects your latest results from every module above into one professional report. Print or save as PDF.