STATCOM (Static Synchronous Compensator), APF (Active Power Filter) and SVG (Static Var Generator) are devices used in power quality management in electric power systems. Although they may appear similar in that they all use power electronics technology to improve grid conditions, they have notable differences in application and functionality.
STATCOM (Static Synchronous Compensator)
- Primarily designed to provide reactive power support dynamically at medium voltage and high voltage by means of a step-up transformer.
- Capable of injecting or absorbing reactive power even when the system voltage is low.
- It uses a voltage source converter (VSC) to synthesize an AC voltage that is injected into the system.
- It improves voltage stability and can help with voltage regulation at the point of connection.
- It has the ability to contribute to system stability by dynamically supporting load variations and damping power oscillations.
- It has the ability to correct harmonic distortion, flicker and unbalance problems.
APF (Active Harmonic Filter)
- Specifically designed to filter harmonics, providing current to selectively cancel harmonics in the low voltage network.
- It can improve the power factor, but its main function is to clean the current of harmonics generated by non-linear loads.
- It operates by detecting harmonic currents in the network and then generates a compensating current that is exactly opposite in phase to the detected harmonics.
- It is particularly useful in installations with a large amount of electronic equipment that can introduce harmonic distortions in the network.
- The 4-wire versions also have some ability to help compensate for load imbalance.
SVG (Static Var Generator)
- Also known as a synchronous reactive power compensator, the SVG is similar to the STATCOM in that both provide or absorb reactive power.
- SVGs are usually simpler than STATCOMs, concentrating on reactive power compensation to improve power factor and handle load imbalances
- Like STATCOMs, they use VSC inverters but are often optimized for steady-state reactive power compensation applications rather than dynamic applications.
- They are not designed to handle power quality issues such as dynamic voltage regulation or power swing mitigation as efficiently as a STATCOM.
In summary, although all these devices contribute to improving power quality, STATCOMs are more suitable for applications where dynamic voltage control and stability in grid power quality are required, APFs are focused on harmonic elimination and SVGs are mainly used for steady-state reactive power compensation.
