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FACTS-Based Transmission Voltage Control

Interactive virtual laboratory for investigating voltage regulation using shunt FACTS controllers — Static VAR Compensator (SVC) and Static Synchronous Compensator (STATCOM).
Receiving voltage
—
pu
Voltage regulation
—
%
FACTS Q support
—
pu
Load-bus angle
—
degrees
Line current
—
pu
System state
—
—

Interactive Transmission Network

Three-Phase Transmission System — Shunt FACTS Voltage Control Single-line representation with dynamic reactive-power compensation GENERATOR / GRID Vs ∠ 0° Transmission corridor Z ≈ jX X = 0.40 pu RECEIVING-END BUS Vr = 1.00 pu PL + jQL SVC STATIC VAR COMPENSATOR TCR / TSC Q = +0.00 pu P + jQ Reactive support

Publication-Style Phasor Diagram

Receiving-End Voltage Phasor Construction Vector relation: Vₛ = Vᵣ + jXI — angles and magnitudes calculated from the simulated operating point Real axis j-axis Vᵣ jXI Vₛ I δ φ PHASOR DATA Vₛ magnitude 1.00 pu Vᵣ magnitude 1.00 pu Line current 0.00 pu Power angle δ 0° Current angle φ 0° VECTOR LEGEND Receiving voltage Vᵣ Reactive drop jXI Sending voltage Vₛ Line current I

Live Voltage & Reactive-Power Indicators

1.00 RECEIVING VOLTAGE 0.80 — 1.20 pu
0.00 FACTS Q SUPPORT −1.0 — +1.0 pu

Voltage Profile vs Reactive Loading

Uncompensated SVC STATCOM Vref

Reactive-Power Support

Load Q FACTS Q Net Q

Live Mathematical Model & Calculations

1. Transmission-line power transfer

P r ≈ V s V r X sin ⁡ δ

2. Receiving-end voltage approximation

V r ≈ V s 2 − 2 X Q net

3. Net reactive power

Q net = Q L − Q FACTS

4. SVC model

I SVC = B SVC V r
Q SVC = B SVC V r 2

5. STATCOM model

I STATCOM ≈ V c − V r X
Q STATCOM ≈ V r I STATCOM

6. Voltage regulation

VR = V s − V r V s × 100 %
Calculated quantity Value
Vs —
Vr —
X —
PL —
QL —
QFACTS —
Qnet —
|I| —
δ —
Voltage regulation —

SVC vs STATCOM — Engineering Comparison

Parameter SVC STATCOM
Converter type Thyristor controlled Voltage-source converter
Reactive element Variable susceptance Converter voltage source
Shunt connection Yes Yes
Voltage control Fast Very fast
Low-voltage reactive current Decreases with voltage Can remain strongly controllable
Typical application Voltage support / power factor Dynamic voltage stabilization

Virtual Laboratory Observation

The receiving-end voltage is strongly influenced by transmission reactance and reactive loading. Increasing QL or X increases the voltage drop across the transmission corridor.

An SVC changes its effective shunt susceptance to inject or absorb reactive power. Its reactive-power output is approximately proportional to Vr2.

A STATCOM regulates reactive current through a controllable converter voltage. The simulation therefore illustrates why STATCOM-based compensation can provide strong voltage support during depressed-voltage conditions.

Go to simple version

Go to live simulation of voltage control with fault dynamics version