Flexible AC Transmission Systems (FACTS) are advanced technologies that enhance the controllability, stability, and power transfer capabilities of electrical power grids. These systems play a crucial role in modern power systems, especially with the increasing integration of renewable energy sources.

Why is a Flexible AC Transmission System Needed?

FACTS are needed to address the growing challenges in power transmission, including:

• Increased Power Demand: As electricity demand grows, existing transmission lines need to carry more power without overloading.
• Grid Stability: FACTS help maintain grid stability by providing real-time control over power flow and voltage levels.
• Renewable Energy Integration: FACTS facilitate the integration of variable renewable energy sources, ensuring consistent and reliable power delivery.

Features of Flexible AC Transmission Systems (FACTS)

FACTS offer several features that make them essential for modern power grids:

• Dynamic Voltage Control: FACTS can adjust voltage levels in real time to prevent voltage sags and swells.
• Power Flow Control: FACTS provide precise control over power flow, optimizing the use of existing transmission lines.
• Enhanced System Stability: FACTS improve the stability of power systems by mitigating issues like oscillations and instability.

Protection and Control of FACTS

The protection and control of FACTS involve complex algorithms and systems designed to monitor and manage power flow, voltage levels, and other critical parameters. Advanced control systems ensure the safe and efficient operation of FACTS devices.

Hardware for Control and Protection

The hardware for control and protection in FACTS includes:

• Sensors and Measurement Devices: Monitor voltage, current, and other electrical parameters.
• Controllers: Process data and send commands to FACTS devices to regulate power flow and voltage.
• Protection Relays: Provide safety mechanisms to prevent damage to the system in case of faults.

Converter for FACTS

Converters are essential components of FACTS, responsible for converting AC to DC and vice versa. These converters enable the precise control of power flow and voltage levels, which is crucial for the effective operation of FACTS.

What is the Power Factor?

The power factor is a measure of how effectively electrical power is being used. A higher power factor indicates more efficient power usage, while a lower power factor can lead to increased energy losses.

Unity Power Factor Test Circuit

A unity power factor test circuit is used to ensure that the power factor is close to 1, meaning that the electrical power is being used efficiently with minimal reactive power.

4 Types of FACTS Controllers

There are four main types of FACTS controllers:

• Series Controllers: Control power flow by injecting voltage into the line.
• Shunt Controllers: Regulate voltage by injecting current into the system.
• Combined Series-Shunt Controllers: Offer both series and shunt capabilities.
• Combined Series-Series Controllers: Manage power flow between multiple lines.

2 Types of Series Controllers

Two types of series controllers are:

• Thyristor-Controlled Series Capacitor (TCSC): Used to increase the power transfer capability of transmission lines.
• Static Synchronous Series Compensator (SSSC): Provides precise control of power flow by injecting voltage in series with the transmission line.

2 Parallel Controllers

Two types of parallel controllers are:

• Static Var Compensator (SVC): Controls voltage by regulating reactive power in parallel with the transmission line.
• Static Synchronous Compensator (STATCOM): Provides fast and accurate voltage regulation by controlling reactive power.

A Series-Shunt Controller – Unified Power Flow Controller

The Unified Power Flow Controller (UPFC) is a series-shunt controller that offers comprehensive power flow management. It can control voltage, impedance, and phase angle, making it one of the most versatile FACTS devices.

Steady-State Voltage Control using SVC for Flexible AC Transmission Systems

The Static Var Compensator (SVC) is used for steady-state voltage control in FACTS. By regulating reactive power, the SVC maintains the desired voltage levels in the transmission system, ensuring stability and reliability.

Flexible AC Transmission System by SVC

The SVC plays a crucial role in Flexible AC Transmission Systems by providing dynamic reactive power support. This helps in maintaining voltage stability, reducing losses, and improving the overall efficiency of the power grid.

Transformer Power Management

Transformers in FACTS are used for power management, including voltage regulation and impedance control. Proper transformer management ensures the efficient operation of the transmission system and prevents overloading.

Influence of Reactive Power Flow on Power System Voltage

Reactive power flow has a significant impact on power system voltage. Excessive reactive power can lead to voltage instability, while insufficient reactive power can cause voltage drops. FACTS devices help in managing reactive power flow to maintain voltage stability.

Reactive Power Compensation in Power Transmission System

Reactive power compensation is essential for maintaining voltage stability and reducing losses in the power transmission system. FACTS devices provide dynamic reactive power compensation, ensuring the efficient operation of the grid.

Effects of Reactive Power Flow

Reactive power flow affects the voltage levels and stability of the power system. Proper management of reactive power is crucial for preventing voltage instability and ensuring the smooth operation of the transmission system.

IGBT Applications

Insulated Gate Bipolar Transistors (IGBTs) are widely used in FACTS devices for switching and controlling power flow. IGBTs offer high efficiency, fast switching, and reliability, making them ideal for use in modern power electronics.

Modeling of Flexible AC Transmission System Devices

Modeling of FACTS devices involves simulating their behavior under various operating conditions. Accurate modeling is essential for designing effective control strategies and ensuring the reliability of the power system.

STATCOM Modeling for Voltage and Angle Stability Studies

STATCOM modeling is used to study voltage and angle stability in power systems. By simulating the behavior of STATCOM under different scenarios, engineers can design systems that maintain stability even under challenging conditions.

New Protection Schemes in Smarter Power Grids With Higher Penetration of Renewable Energy Systems

The integration of renewable energy sources into the power grid presents new challenges for protection schemes. FACTS devices play a critical role in developing new protection schemes that ensure the safety and reliability of smarter power grids.

The Nonlinear Internal Control of STATCOM: Theory and Application

The nonlinear internal control of STATCOM involves advanced control techniques that allow for precise voltage and power flow management. Understanding the theory and application of these controls is essential for optimizing the performance of STATCOM in power systems.

Review of FACTS Technologies and Applications for Power Quality in Smart Grids With Renewable Energy Systems

FACTS technologies are essential for maintaining power quality in smart grids, especially with the increasing penetration of renewable energy systems. A review of FACTS applications highlights their role in ensuring grid stability, voltage control, and power flow management.

Mastering the Integration of Renewables by Stabilizing the Grid

Mastering the integration of renewable energy sources requires effective grid stabilization techniques. FACTS devices provide the necessary tools to manage the variability of renewables, ensuring a stable and reliable power supply.