Differences between STATCOM, Active Harmonic Filter and SVG

Power quality is crucial for the efficient and stable operation of electrical systems. Poor power quality can lead to issues such as voltage instability, Harmonics, and power factor problems, which can damage equipment and reduce system efficiency. To address these challenges, various solutions are available, including STATCOM (Static Synchronous Compensator), APF (Active Power Filter), and SVG (Static Var Generator). While all three devices use power electronics to improve grid performance, they differ significantly in their application and functionality.

STATCOM, APF, and SVG are specialized devices designed to address different aspects of Power Quality. Each of these devices offers unique advantages depending on the specific requirements of the electrical system.

Static Synchronous Compensator (STATCOM)

The Static Synchronous Compensator (STATCOM) is primarily designed to provide dynamic reactive power support in medium and high-voltage systems, typically using a step-up transformer.

• Reactive Power Support: It can inject or absorb reactive power even when system voltage is low, improving overall power quality.
• Voltage Source Converter (VSC): STATCOM utilizes a voltage-source converter to generate and inject an AC voltage into the system, allowing for precise control of reactive power.
• Voltage Stability: It enhances voltage stability and aids in voltage regulation at the point of connection, ensuring a reliable power supply.
• System Stability: STATCOM contributes to system stability by dynamically responding to load variations and damping power oscillations, improving system performance.
• Harmonic and Flicker Mitigation: Additionally, STATCOM helps correct harmonic distortion, flicker, and unbalance issues, ensuring a smoother and more efficient power flow.

The main components of STATCOM’s circuit include a voltage source inverter and a parallel DC capacitor, both powered by high-power electronics. This system differs from the traditional SVC design by using inverters for reactive power compensation instead of capacitors and reactors.

The three-phase AC voltage (Vo) is synchronized with the system voltage (vs) through a transformer. Reactive power output is controlled by adjusting Vo. Capacitive reactive power is generated when Vo exceeds vs, while inductive reactive power is produced when Vo is less than vs. The equipment’s reactive power is regulated by output current, which is mostly unaffected by system voltage.

Though similar to a synchronous condenser, STATCOM is fully static and sometimes called a static tuner. Unlike the synchronous condenser, STATCOM offers better dynamic performance, rapid response, and minimal energy loss.

Gate Turn-Off thyristors (GTOs) are used to prevent commutation failure. The DC capacitor is small and supports the DC voltage, making the device compact and cost-effective.

Active Harmonic Filter (AHF)

The Active Harmonic Filter is designed to filter and cancel harmonics in low voltage networks. It mainly addresses harmonic distortion caused by non-linear loads, improving power quality.

By detecting harmonic currents, it generates a compensating current opposite in phase to cancel out the harmonics. It also helps improve the power factor and, in the case of 4-wire versions, can assist in balancing loads. This filter is particularly useful in environments with heavy electronic equipment, where harmonic distortions are common.

Static Var Generator (SVG)

The Static Var Generator, also known as a synchronous reactive power compensator, is similar to the Static Synchronous Compensator (STATCOM) in that it provides or absorbs reactive power. However, SVGs are generally simpler and focus primarily on steady-state reactive power compensation, improving power factor and addressing load imbalances. Using voltage source converters (VSC), SVGs are optimized for steady-state applications, unlike STATCOMs, which handle dynamic power quality issues like voltage regulation or power swing mitigation more efficiently.

Summary

While all these devices help improve power quality, their applications differ. STATCOMs are ideal for dynamic voltage control and grid stability, APFs specialize in harmonic elimination, and SVGs are used for steady-state reactive power compensation.

Contact us for expert guidance:

Intone Power is the biggest OEM manufacturer of low-voltage AHF and SVG with more than 15 years' experience. All products hold certifications for ISO9001, CE, and CQC standards, and type test reports support them.

For more information on how our Active Harmonic Filter and Static Var Generator can help compensate reactive power and improve power quality: sales@intonepower.com

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