IEC 60392: Capacitors for Power Transformers — Shunt Reactive Compensation and Series Voltage Regulation

Substation Capacitor Banks — Compensating Reactive Power, Boosting Voltage Stability

IEC 60392:1972 specifies capacitors for power transformers. Substation shunt capacitor banks compensate inductive reactive power (power factor correction) — switched in during peak load to raise PF from 0.8 to above 0.95, reducing line losses and voltage drop.

Reactive compensation capacity:
Qc = P × (tan φ₁ − tan φ₂)
Example: P=100MW, cos φ₁=0.8→0.95
Qc = 100 × (0.75 − 0.33) = 42 Mvar

TNLab — Reactive compensation is “the cheapest way to increase grid transfer capacity” — every Mvar of capacitor compensation releases approximately 1.2 MW of line capacity.