What Is the Per-Unit System Base Change Calculator?
The per-unit system simplifies power system calculations by removing ideal transformer turns ratios and unifying network equations.
How Does the Per-Unit System Base Change Calculator Work?
Scales impedance inversely with power base and quadratically with voltage ratio.
Per-Unit System Base Change Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Z_pu(new) = Z_pu(old) · (V_old / V_new)² · (S_new / S_old)
Standard per-unit transformation formula across voltage and power bases.
How to Use the Per-Unit System Base Change Calculator
- Enter nameplate per-unit impedance and ratings.
- Specify target system base voltage and MVA.
Step-by-Step Example Calculation
50 MVA Generator Re-basing
Input Values:
zOldPu:0.1
vOldKv:13.8
vNewKv:13.2
sOldMva:50
sNewMva:100
Worked Steps: 50 MVA generator re-based to common 100 MVA grid base.
Understanding Your Result
Primary output indicates new per-unit impedance.
Summary displays base impedance and actual physical Ohms.
Factors That Affect the Result
- Base selection ratio.
When Should You Use This Calculator?
- Power flow studies, short circuit fault analysis, and protection relay settings.
Assumptions & Limitations
- Applies to linear balanced impedances.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard power systems base conversion equation.