Static Var Generator SVG Explained for Power Factor Correction

2026-01-08 12:53:36

Background: From Passive to Dynamic Compensation

As industrial power systems become more dynamic, traditional Capacitor-based compensation struggles to maintain stable power factor under rapidly changing loads. Static Var Generators (SVGs) address this limitation by providing continuously adjustable reactive power using power electronic converters. Within IEC-oriented system design, SVGs are classified as dynamic compensation devices capable of responding within milliseconds.

Operating Principle of SVG

An SVG operates by generating or absorbing reactive current through a voltage-source inverter. By controlling the phase relationship between output current and system voltage, the SVG can operate in either capacitive or inductive mode.

Unlike capacitor banks, which supply reactive power in discrete steps, SVGs provide smooth, stepless compensation. This allows precise tracking of reactive power demand even during fast load transients.

Control and Response Characteristics

SVG Controllers continuously measure system voltage, current, and power factor. Advanced control algorithms calculate the required reactive current and command the inverter accordingly.

Typical response times are in the range of a few milliseconds, making SVGs suitable for: - Rapidly fluctuating industrial processes - Systems with frequent motor starts - Networks sensitive to voltage flicker

Advantages and Engineering Trade-Offs

Key advantages include: - Bidirectional reactive power control - No resonance with system inductance - Effective operation under low load conditions

However, SVGs introduce higher initial cost and require careful thermal and electromagnetic compatibility design. Their efficiency and reliability depend on semiconductor performance and cooling strategies.

FAQ

Can SVGs replace capacitor banks entirely?

In many dynamic applications, yes. In stable load environments, hybrid solutions are often more economical.

Do SVGs mitigate harmonics?

They primarily address reactive power; harmonic mitigation requires additional filtering functions.