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- Smart Grid Introduction
- What is an Electric Grid?
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- What is a Smart Grid?
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- Smart Grid - Feeder Automation
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- Smart Grid - FACTS
- HVDC Transmission
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- SCADA in Smart Grid
- Smart Grid - DMS
- Smart Grid - OMS
- Volt/VAR Control
- Smart Grid - FMSR
- Smart Grid - HEDT
- Phase Shifting Transformers
- Smart Grid - PHEV
- Advanced Metering Infrastructure
- Smart Meters - Introduction
- Smart Meters - AMI
- Smart Meters - AMIS
- Communication Architecture
- Drivers & Benefits
- Phasor Measurement Unit
- Intelligent Electronic Devices
- Power Quality Management
- Power Quality in Smart Grid
- Power Quality Issues
- Power Quality Monitoring Techniques
- Power Quality Conditioners
- Electromagnetic Compatibility (EMC)
- Power Quality Audit
- Smart Grid Communication
- Smart Grid Communication
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Volt / VAR Control in Smart Grid
In a smart grid, voltage stability and reactive power control are two related and important concepts. The voltage and reactive power control is crucial for improving efficiency and reliability of the power distribution system. In this chapter, we will learn about voltage and reactive power control.
The integration of volt/var control in smart grid results in several benefits like voltage stability, reduced losses in power lines, improved power quality, uninterrupted integration of renewable energy resources, and more.
What is Volt / VAR Control?
Volt/VAR Control (VVC) is an important technical concept in modern power system and smart grids. From the basics, we known that voltage is the electrical pressure between two points that forces electric current to flow, while VAR or Reactive Power is a component of electrical power that oscillates between the source and load and responsible for establishing magnetic fields in electrical machines like generators, transformers, induction motors, etc.
In an electrical power system, there are different types of load devices that contain reactive power components such as inductors and capacitors. These load devices put extra strain on the grid by drawing high amount of electric current. This high electric current can result in over-voltage or under-voltage conditions that can heat up and damage the system equipment like transformers, conductors, etc.
Therefore, it is important to control the reactive power flow and the voltage in the system to prevent such undesirable conditions to happen. For this purpose, a technology is involved that manages the voltage levels and reactive power flow through the power system and it is referred to as the Volt/VAR Control (VVC).
Significance of Volt / VAR Control
In a smart grid, voltage stability and controlled reactive power flow are two important aspects. Therefore, Volt/VAR control is very crucial for the following reasons −
- VVC enables to maintain the voltage levels within an acceptable limit. This ensures optimized and reliable operation of the devices.
- VVC maintains the voltage levels almost constant within a specified range. This results in enhanced power quality.
- VVC controls the reactive power flow through the distribution network and reduces the system currents. This results in reduced energy losses within the network itself.
- Through voltage and reactive power control, VVC also provides ease in integration of renewable energy resources into the grid that have intermittent nature and variable output.
Mian Components of Volt/VAR Control
The Volt/VAR Control used in smart grid consists of several components. Some of the key components of smart grid VVC are explained here −
Voltage Regulator
It is a device used for adjusting the voltage in the distribution network to keep it within a specified limit.
Capacitor Bank
It is a device that consists of a number of static capacitors connected together. The capacitor bank is used in provide reactive power for compensating the reactive power demand, to improve the power factor, and reduce the energy losses.
Advanced Metering Infrastructure (AMI)
It is a system of smart components like sensors, smart meters, and intelligent electronic devices designed to provide real-time monitoring of voltage levels and reactive power flow in the distribution network. It helps the utilities to more precisely perform the voltage and reactive power control.
Smart Inverters
The smart inverters are also the part of Volt/VAR Control. These are used between grid and renewable energy systems and control the voltage levels and reactive power flow between them.
Load Tap Changer (LTC)
It is a device used in power transformers. This provides facility to adjust the voltage ratio of the transformer to control and maintain the output voltage within the desired limit.
Volt/VAR Control Methods
In smart grids, there are several methods used to provide an effective voltage and reactive power control in the system. The following are three most commonly used methods of volt/var control −
- Centralized Control − In this method, a central control system is employed for collecting data from various points in the grid. Using this data, the control manages the voltage levels and reactive power flow in the entire grid.
- Decentralized Control − In this Volt/VAR control method, independent local controllers are provided in different parts of the grid. These controllers manage the voltage levels and reactive power flow in the specific parts of the grid depending the needs of that individual sections.
- Coordinated Control − In this method, the features of centralized and decentralized controls are combined to achieve a better optimized voltage and reactive power control in the grid.
Advantages of Volt/VAR Control
The implementation of Volt/VAR control in smart grid offers the following major advantages −
- It improves the reliability of the distribution system by maintaining the voltage levels within the desired limits.
- VVC controls the reactive power flow in the distribution network and reduces the current levels. Hence, it results in reduced cost of conductors required.
- VVC reduces the energy losses in the distribution network and hence improves the efficiency.
- By reducing the energy losses, VVC also reduces the cost of operation and maintenance of distribution network.
- VVC stabilizes the voltage levels and reduces the fluctuations. Thus, it also improves the power quality.
Conclusion
Volt/VAR Control (VVC) is an important component of a smart grid system as it provides control over voltage levels and reactive power flow in the distribution network. The control of both voltage levels and reactive power in a power system is crucial for efficient and reliable operation of the grid and to maintain power quality.
The implementation of voltage and reactive power control in smart grids offers several advantages such as enhanced efficiency, reduced energy losses, cost minimization, and integration of renewable energy into the grid.