What are the differences APF and SVG?

What is an active filter?
An active power filter is abbreviated as APF. It is a new type of equipment specifically designed for power harmonic control, which is manufactured using modern power electronics technology and digital signal processing technology based on high-speed DSP (Digital Signal Processor) devices.

It consists of two main parts: the instruction current operation circuit and the compensation current generation circuit. The instruction current operation circuit continuously monitors the current in the line and converts the analog current signal into a digital signal, which is then sent to the high-speed digital signal processor (DSP) for processing. The DSP extracts the part of the load harmonic and sends a pulse width modulation (PWM) signal in the form to the compensation current generation circuit to drive the IGBT (insulated gate bipolar transistor), generating a compensation current of the same amplitude as the grid harmonic current but with opposite polarity, which is injected into the grid to compensate or cancel the harmonic current, actively eliminating power harmonics.

What is a dynamic reactive power compensation device?
The dynamic reactive power compensation device is abbreviated as SVG. Its Chinese name is "Static Reactive Power Generator", also known as "High Voltage Dynamic Reactive Power Compensation Generator" or "Static Synchronous Compensator". It refers to a device that performs dynamic reactive power compensation using a self-switching power semiconductor bridge-type converter. SVG is currently the better solution in the field of reactive power control. Compared with traditional synchronous condensers, capacitor-inductor reactors, and traditional SVC methods mainly represented by thyristor-controlled reactors (TCR), SVG has unparalleled advantages.

What are the differences between dynamic reactive power compensation devices and active filters?

Dynamic reactive power compensation devices and active filters are two different types of equipment!

The SVG dynamic reactive power compensation device is used to improve the power factor of the system. It mainly functions to compensate for reactive power. Its response is very fast, meaning it compensates very quickly. However, it has no effect on the control of various frequency harmonics.

APF (Active Power Filter) is mainly used to filter out harmonics in the power grid. It has the ability to compensate for reactive power, and its response speed is faster. Although it can correct the power factor, it cannot achieve a wide range and high precision in compensating reactive power.

However, if your power grid requires both harmonic control and reactive power compensation at the same time, then these two devices can be installed in a cabinet-style configuration for better results.