# Voltage Regulation Report
**Generated:** 01/08/2026, 10:19:24

## Transformer Parameters
| Parameter | Value |
|---|---|
| Rating S_tr | 630 kVA |
| Primary V_p | 20 kV |
| Secondary V_s | 400 V |
| Impedance Z_t | 6% |
| Load current I_load | 500 A |
| Power factor cos φ | 0.9 |
| Feeder R | 0.05 Ω |
| Feeder X | 0.02 Ω |

## Results
| Metric | Value |
|---|---|
| Nominal current I_nom | 909.33 A |
| Feeder voltage drop ΔV | 26.86 V |
| Voltage regulation | 6.7% |
| Tap changer range | ±12.5% (350–450 V) |
| **EN 50160 PoC** | **✅ PASS** |

## Tap Changer Table
| Tap | Tap % | V_tap (V) | V_PoC (V) | Regulation % |
|---|---|---|---|---|
| -8 | -12.5 | 350 | 323.14 | -19.2 |
| -7 | -10.94 | 356.25 | 329.39 | -17.7 |
| -6 | -9.37 | 362.5 | 335.64 | -16.1 |
| -5 | -7.81 | 368.75 | 341.89 | -14.5 |
| -4 | -6.25 | 375 | 348.14 | -13 |
| -3 | -4.69 | 381.25 | 354.39 | -11.4 |
| -2 | -3.12 | 387.5 | 360.64 | -9.8 |
| -1 | -1.56 | 393.75 | 366.89 | -8.3 |
| +0 | +0 | 400 | 373.14 | -6.7 |
| +1 | +1.56 | 406.25 | 379.39 | -5.2 |
| +2 | +3.13 | 412.5 | 385.64 | -3.6 |
| +3 | +4.69 | 418.75 | 391.89 | -2 |
| +4 | +6.25 | 425 | 398.14 | -0.5 |
| +5 | +7.81 | 431.25 | 404.39 | 1.1 |
| +6 | +9.38 | 437.5 | 410.64 | 2.7 |
| +7 | +10.94 | 443.75 | 416.89 | 4.2 |
| +8 | +12.5 | 450 | 423.14 | 5.8 |

## Recommendations
- ⚠️ **WARNING** Voltage regulation 6.7% is in amber zone (6–10%). Consider tap changer range adequacy or feeder conductor upgrade.

## Standards & Methodology
- IEC 60076-1 §5.3: Transformer tap changer range and step size
- IEC 60364-5-52 §525: Voltage drop in feeders
- EN 50160: Point-of-connection voltage limit ±10%
- V_drop = I·√(R²+X²)·cos(φ−atan(X/R))
- Regulation % = (V_no-load − V_full-load) / V_full-load × 100