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FACTS

1. ROLE OR FUNCTIONS FACTS DEVICES AND DIFFERENT COMPENSATION DEVICES FOR STABLE POWER SYSTEM OPERATION PG-SEMINAR PRESENTATION BY Name IDNo Ediris Abrahim Umer RPG/0077/16 Kefale Atinafu RPG/ Shibeshi Wederufael RPG/ Khader Ahmed RPG/ On the Course of: Power systems Dynamics and Stability Department of ELECTRICAL Power ( Power system and Automotion ) At DEFENCE UNIVERSITY, COLLEGE OF ENGINEERING BISHOFTU, ETHIOPIA OCTOBER, 2024 12/9/2023 1

2. Contents Standard or ideal AC grid network COMPENSATION DEVICES What are FACTS? Types of FACTS Controllers Role Or Functions of FACTS FACTS DEVICES and IT’S COMPENSATION MECHANISMS 12/9/2023 2

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4. Motors and Transformers consume reactive power and employing fixed capacitors banks can reduce the load on the generators, but that is not enough 12/9/2023 4

5. Compensation devices Compensation devices are a broad category of devices used in power systems to improve system performance, stability, and power quality. It's important to note that the specific type of compensation device used will depend on the application and the nature of the compensation required. They are designed to compensate for various electrical parameters such as reactive power, voltage, and line impedance. These devices can be deployed in different parts of the power system, such as distribution networks or transmission lines, to regulate voltage levels, control power flow, and enhance system reliability. Compensation devices include capacitors, FACTS Device reactors, and other devices that are specifically used for reactive power compensation or voltage control. Compensation Capacitors : These capacitors are used in power factor correction systems to compensate for reactive power and improve the power factor of electrical systems. They help reduce energy losses and improve the efficiency of power distribution. Automatic Voltage Regulator (AVR): An AVR is used in electrical systems to regulate the output voltage of a generator or power supply. It compensates for voltage fluctuations caused by variations in load or input voltage, ensuring a consistent and stable output voltage. 12/9/2023 5

6. Con’t Compensation Algorithms : In the field of control systems and signal processing, compensation algorithms are used to adjust or compensate for errors or disturbances. These algorithms can be implemented in software or hardware to dynamically modify system parameters, inputs, or outputs to achieve desired performance or stability. The difference between FACTS devices and compensation devices FACTS devices are advanced compensation devices that utilize power electronics and control systems to provide dynamic control and optimization of power flow, voltage stability, and other parameters in real-time. These devices offer greater flexibility and controllability compared to traditional compensation devices. In summary, compensation devices are a broader category that includes devices such as capacitors and reactors used for reactive power compensation and voltage control. On the other hand, FACTS devices are a specific subset of compensation devices that utilize power electronics and advanced control techniques to provide dynamic and real-time control of power flow, voltage stability, and other parameters in power transmission and distribution networks . 12/9/2023 6

7. What are FACTS . 12/9/2023 7

8. Classification of FACTS 12/9/2023 8

9. Short Explanations S eries Controllers The series controller could be a variable impedance or a variable source both are power electronics based. In principle, all series controllers inject voltage in series with the line. The main purpose of series compensation in power systems is to decrease the reactive impedance of the transmission line to reduce voltage drop over long distances and to reduce the Ferranti effect. These series controllers includes, TCSC, SSSC, TSSC, TCSC, and TCSR. Shunt Controllers The shunt controllers may be variable impedance connected to the line voltage causes a variable current flow hence represents injection of current into the line. These shunt controllers includes, STATCOM, STAT VAR(SVC) and TCR. Combined Series-series Controllers The combination could be separate series controllers or unified series-series controller-Interline Power Flow Controller. E.g inter line power flow controller (IPFC). Combined Series-shunt Controllers The combination could be separated series and shunt controllers or a unified power flow controller. E.g Unified power flow controller (UPFC). 12/9/2023 9

10. Role or Functions of FACTS Devices Some of the key functions of FACTs devices include: Increase loading capacity of transmission lines. Prevent blackouts. Improve generation productivity. Voltage Control : FACTs devices can regulate voltage levels within desired limits by injecting or absorbing reactive power. This helps maintain voltage stability and improve power transfer capability. Power Flow Control : FACTs devices enable control over active power flow in transmission lines. By adjusting the line impedance, they can redirect power flow to relieve congestion and optimize power transfer. Damping of Power System Oscillations : FACTs devices can provide supplementary damping to power system oscillations, improving the transient stability of the system. They achieve this by injecting or absorbing reactive power in a controlled manner . Enhancing Grid Stability : FACTs devices help mitigate voltage fluctuations and grid instability caused by sudden changes in load or system disturbances. By regulating voltage and power flow, they contribute to stable grid operation. 12/9/2023 10

11. FACTS DEVICES and IT’S COMPENSATION MECHANISMS There are various types of FACTs devices, each with its own compensation mechanism and characteristics. Some commonly used FACTs devices for stable power system operation include Static Var Compensator Static Synchronous Compensator (STATCOM) Static Synchronous Series Compensator (SSSC): Unified Power Flow Controller (UPFC) Inter-line power flow control (IPFC) Static Var (Volt- amper reactive) Compensator (SVC ) SVC is a shunt-connected device that injects or absorbs reactive power to regulate voltage and improve system stability. It consists of a thyristor -controlled reactor (TCR) and a capacitor bank. The crucial equipment which is included in this device is TCR and TSR which are a thyristor -controlled capacitor and thyristor -controlled reactor. 12/9/2023 11

12. Static Synchronous compensator(StatCOM) 12/9/2023 12

13. . It is a shunt device of the Flexible AC Transmission Systems (FACTS) family using power electronics to control power flow and improve transient stability on power grids. The STATCOM regulates voltage at its terminal by controlling the amount of reactive power injected into or absorbed from the power system. When system voltage is low, the STATCOM generates reactive power (STATCOM capacitive). When system voltage is high, it absorbs reactive power (STATCOM inductive).Similarly to the SVC the STATCOM can provide instantaneous and continuously variable reactive power in response to grid voltage transients enhancing the grid voltage stability. The STATCOM regulates voltage at its terminal by controlling the amount of reactive power injected into or absorbed from the power system. When system voltage is low, the STATCOM generates reactive power (STATCOM capacitive). STATCOM is GTO or IGBT based. 12/9/2023 13

14. STATIC SYNCHRONOUS SERIES COMPENSATOR(SSSC) 12/9/2023 14

15. . It is a series-connected device that uses VSC technology to regulate transmission line parameters. It can control the line impedance and improve power flow control and transient stability. It can be considered as a FACTS controller acting like a controlled series capacitor. It compensates the inductive voltage drop in the line by inserting capacitive voltage in order to reduce the effective inductive reactance of the transmission line. In contrast to series capacitor, the SSSC is able to maintain a constant compensating voltage in case of variable line current or controls the amplitude of the injected compensating voltage independent of amplitude of line current. 12/9/2023 15

16. UNIFIED POWER FLOW CONTROLLER (UPFC) 12/9/2023 16

17. . The UPFC is a combination of a static synchronous compensator (STATCOM) and a static synchronous series compensator (SSSC) coupled via a common DC voltage link. The main advantage of the UPFC is to control the active and reactive power flows in the transmission line. If there are any disturbances or faults in the source side, the UPFC will not work. The UPFC operates only under balanced sine wave source. The controllable parameters of the UPFC are reactance in the line, phase angle and voltage.  Fig 4 Unified Power flow controller(UPFC) 12/9/2023 17

18. Inter-line power flow control (IPFC) The term "IPFC" stands for "Interline Power Flow Controller." It is a type of Flexible AC Transmission System (FACTS) device used in electrical power systems. The Interline Power Flow Controller (IPFC) is designed to control and optimize power flow in multi-line transmission systems. It consists of several voltage source converters (VSCs) connected in series with transmission lines. The VSCs inject controllable voltage into the lines, which allows for the real and reactive power flow to be controlled independently. Here are some key facts about IPFC devices: Power Flow Control: The IPFC device can independently control the active power (real power) and reactive power flow on multiple transmission lines. By manipulating the injected voltage, it can change the impedance of the transmission lines, thereby influencing the power flow. Voltage Regulation: IPFC devices can regulate the voltage levels in transmission lines by injecting or absorbing reactive power. This helps in maintaining a stable voltage profile throughout the network. Series Compensation: IPFC provides series compensation by injecting voltage in series with the transmission lines. This compensates for the line impedance and helps in reducing transmission line losses and increasing the transfer capacity of the line. 12/9/2023 18

19. Con’t Dynamic Control: IPFC devices can respond rapidly to changing system conditions and adjust the injected voltage accordingly. This enables them to mitigate congestion, improve system stability, and enhance overall system performance. Installation Location: IPFC devices are typically installed at substations or along transmission lines, strategically placed to optimize power flow and voltage regulation in the network. Benefits: IPFC devices offer several benefits, including increased transmission capacity, improved voltage stability, reduced transmission losses, and enhanced system controllability and flexibility. Fig 6 schematic diagram of IPFC 12/9/2023 19