Power Factor Correction Panel（APFC）

What is APFC Panel?

Automatic Power Factor Correction (APFC Panel) is an approach that combines the advantages of traditional reactive power compensation devices like capacitor banks and reactors with modern power electronics-based devices such as Static Var Generators (SVGs). This hybrid power factor correction aims to optimize both cost and performance, providing an efficient and flexible solution for maintaining power factor, improving voltage stability, and enhancing power quality in electrical power systems.

How a APFC Panel Works?

Base Load Compensation: The capacitor banks and reactors handle the base reactive power needs of the system. They provide the bulk of the reactive power, reducing the load on the SVG and improving overall efficiency.

Dynamic Compensation: The SVG responds to rapid changes in reactive power demand, fine-tuning the compensation provided by the capacitor banks and reactors. The SVG can quickly adjust to transient conditions, voltage fluctuations, and dynamic loads.

Friendly monitoring : The control system continuously monitors key electrical parameters such as voltage, current, and power factor in the power system.

Single Line Diagram of Power Factor Correction Panel

Intelligent Control Coordination: The intelligent control system dynamically adjusts the operation of the capacitor banks, reactors, and SVGs. It can switch capacitor banks and reactors on or off as needed and modulate the output of the SVG in real-time to achieve optimal reactive power compensation.

Optimization: The control system aims to minimize losses and maximize efficiency. By using capacitor banks and reactors for bulk compensation, the SVG is only used for fine-tuning and rapid adjustments, reducing its operational burden and extending its lifespan.

Automatic Power Factor Correction Panel

Automatic Power Factor Correction Panel

Components of APFC

Static Var Generators (SVGs): Provide dynamic, real-time reactive power compensation using power electronics. They can quickly adjust to both capacitive and inductive reactive power demands.

Capacitor Banks: Provide bulk, fixed capacitive reactive power compensation. They are efficient for steady-state reactive power needs but lack dynamic response capability.

Reactors: Provide bulk, fixed inductive reactive power compensation. They counteract excessive capacitive reactive power or manage overvoltage situations.

Control System: Coordinates the operation of the capacitor banks, reactors, and SVGs to optimize overall reactive power compensation.

Static var generator module in APFC Panel

Capacitors in APFC Panel

Reactors in APFC Panel

Thyristor in APFC Panel

Workflow of APFC

Steady-State Operation:

The control system assesses the reactive power demand under steady-state conditions.

Capacitor banks and reactors are deployed to provide the necessary base reactive power compensation.

The SVG operates in a low-power mode or standby, ready to respond to dynamic changes.

Dynamic Conditions:

When there is a sudden change in load or power factor (e.g., a large motor starts or stops), the control system detects the deviation.

The SVG rapidly adjusts its output to compensate for the immediate change, providing or absorbing reactive power as needed.

If the deviation persists, the control system may switch additional capacitor banks or reactors on or off to handle the new steady-state condition.

Principle of hybrid power factor correction.

Harmonic Mitigation:

The SVG can also help mitigate harmonics generated by non-linear loads. It provides harmonic compensation by injecting currents that cancel out the harmonics, thus improving power quality.

Voltage Stability:

The combination of static and dynamic compensation helps maintain stable voltage levels. The capacitor banks and reactors handle long-term voltage support, while the SVG manages short-term fluctuations.

Comparison with Traditional Solutions

Example Scenario

Imagine an industrial plant with varying loads due to different machinery operating at different times:

Steady-State Operation:

● During normal operation, capacitor banks provide the necessary reactive power to maintain a good power factor.

● Reactors are used if there is excessive capacitive power that needs to be counteracted.

Dynamic Load Changes:

● When a large motor starts, it causes a significant drop in power factor.

● The control system detects this and activates the SVG to quickly provide the necessary reactive power to stabilize the power factor and voltage.

Transient Conditions:

● If a sudden load change occurs, the SVG responds instantly to mitigate any voltage dips or spikes.

● The control system adjusts the static components as needed for the new load condition, ensuring optimal performance.

Benefits of APFC

Cost-Effectiveness: Utilizing capacitor banks and reactors for bulk compensation reduces the overall cost compared to using SVGs alone.

Improved Efficiency: Static components handle most of the reactive power, enhancing overall system efficiency.

Enhanced Power Quality: The SVG provides rapid response to dynamic changes, improving voltage stability and reducing harmonics.

Scalability and Flexibility: The system can be easily scaled and tailored to specific requirements.

Reduced Footprint: The hybrid approach optimizes space usage by combining compact dynamic compensation with static components.

APFC Panels

APFC panels

In summary, an APFC offers a balanced and optimized solution for reactive power compensation, leveraging the strengths of both traditional capacitor banks/reactors and modern SVGs. This approach provides cost-effective, efficient, and high-quality power compensation suitable for a wide range of applications.