scholarly journals ANN based SVC FACTS Controller to Enhance Voltage Stability of Multi-Machine Power System

2019 ◽  
Vol 8 (10) ◽  
pp. 381-387
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Voltage Stability ◽  
Reactive Power ◽  
Short Circuit ◽  
Supply And Demand ◽  
Optimal Location ◽  
Voltage Sensitivity ◽  
Index Value ◽  
Weak Bus

Voltage stability is the most vital phenomena in power systems which may be disturbed by the mismatch between the reactive power supply and demand. The occurrence of internal faults in the equipment and short circuit faults also there may be voltage collapse at the buses. Voltage stability can be improved using Static VAR Compensator (SVC) which is a shunt device. It can generate or absorb reactive power in a controlled manner such that it can enhance voltage stability of the system. LIndex method is used to determine voltage sensitivity at each bus and the bus having highest L- index value can be considered as a weak bus which is the optimal location of FACTS controller. The investigation is made to observe how susceptance in susceptance model and firing angle in firing angle model of the SVC is predicted to enhance the voltage at each bus by the artificial neural network under chaotic load. Standard IEEE 5 bus and 30 bus systems are considered as test systems and simulations are performed in MATLAB software.

scholarly journals Voltage Stability of Power Systems with Renewable-Energy Inverter-Based Generators: A Review

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 115
Author(s):  
Nasser Hosseinzadeh ◽  
Asma Aziz ◽  
Apel Mahmud ◽  
Ameen Gargoom ◽  
Mahbub Rabbani
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Voltage Stability ◽  
Reactive Power ◽  
Power Grid ◽  
Renewable Energy Sources ◽  
Electrical Power ◽  
System Stability ◽  
Special Issue ◽  
Synchronous Generators

The main purpose of developing microgrids (MGs) is to facilitate the integration of renewable energy sources (RESs) into the power grid. RESs are normally connected to the grid via power electronic inverters. As various types of RESs are increasingly being connected to the electrical power grid, power systems of the near future will have more inverter-based generators (IBGs) instead of synchronous machines. Since IBGs have significant differences in their characteristics compared to synchronous generators (SGs), particularly concerning their inertia and capability to provide reactive power, their impacts on the system dynamics are different compared to SGs. In particular, system stability analysis will require new approaches. As such, research is currently being conducted on the stability of power systems with the inclusion of IBGs. This review article is intended to be a preface to the Special Issue on Voltage Stability of Microgrids in Power Systems. It presents a comprehensive review of the literature on voltage stability of power systems with a relatively high percentage of IBGs in the generation mix of the system. As the research is developing rapidly in this field, it is understood that by the time that this article is published, and further in the future, there will be many more new developments in this area. Certainly, other articles in this special issue will highlight some other important aspects of the voltage stability of microgrids.

scholarly journals Optimal Voltage Stability Improvement under Contingencies using Flower Pollination Algorithm and Thyristor Controlled Series Capacitor

2018 ◽  
Vol 12 (2) ◽  
pp. 497
Author(s):  
Zulkiffli Abdul Hamid ◽  
Ismail Musirin ◽  
Muhammad Amirul Adli Nan ◽  
Zulkifli Othman
Keyword(s):  
Power Systems ◽  
Voltage Stability ◽  
Reactive Power ◽  
Computation Time ◽  
Flower Pollination Algorithm ◽  
Stability Problems ◽  
Total Transmission ◽  
Flower Pollination ◽  
Thyristor Controlled Series Capacitor ◽  
Series Capacitor

Recent power systems necessitate for maintaining a safe voltage stability as the number of problems such as contingencies and reactive power insufficiency are increasing. In this paper, installation and sizing of Flexible Alternating Current Transmission System (FACTS) devices have been introduced for solving the voltage stability problems under contingencies. The FACTS device to be used is Thyristor Controlled Series Capacitor (TCSC). Besides improving the voltage magnitude at all buses to a desired level, installation of TCSC at proper locations can minimize total transmission losses of the system. To conduct the sizing task, the newly developed Flower Pollination Algorithm (FPA) has been implemented as the engine for optimization. Through experimentation, the results proved that the proposed placement and sizing technique has successfully mitigated the voltage stability problems. In addition, the computation time for FPA’s convergence was tolerable with optimum results.

scholarly journals Secondary power systems for videometric complex "Fregat"

2018 ◽  
Vol 30 ◽  
pp. 134-142
Author(s):  
Pavlin Gramatikov ◽  
Roumen Nedkov ◽  
Doino Petkov
Keyword(s):  
Power Systems ◽  
Power Supply ◽  
Measuring Equipment ◽  
Short Circuit ◽  
Technical Documentation ◽  
Supply Systems ◽  
Secondary Power

The power supply for the video-spectrometric complex (VSC) "Fregat" is being considered. This secondary power supply systems have the following functions: Reception and switching of the voltages; Protection from overload and short circuit in the internal circuits and the exit circuits; Transformation of primary voltage in stabilized secondary voltages; Galvanically untethered secondary circuits by primary and Hull; Protection of the users from the electromagnetic noises; Provision of "Cold" and "Hot" reserve, etc. A set of technical documentation and test-measuring equipment for testing were created. Four sets of Secondary Power Systems for "Fregat" are designed and implemented for two flights to planet Mars.

scholarly journals Optimal Placement and Sizing of SVC for Improving Voltage Profile of Power System

2011 ◽  
pp. 146-150
Author(s):  
Shraddha Udgir ◽  
Sarika Varshney ◽  
Laxmi Srivastava
Keyword(s):  
Power Systems ◽  
Power System ◽  
Capital Investment ◽  
Reactive Power ◽  
Test System ◽  
Vital Role ◽  
Optimal Location ◽  
Optimal Placement ◽  
Voltage Profile ◽  
Stability Margins

In emerging electric power systems, increased transactions often lead to the situations where the system no longer remains in secure operating region. The flexible AC transmission system (FACTS) controllers can play a vital role in the power system security enhancement. However, due to high capital investment, it is necessary to place these controllers optimally in a power system. FACTS devices can regulate the active and reactive power control as well as adaptive to voltage-magnitude control simultaneously because of their flexibility and fast control characteristics. Placement of these devices at optimal location can lead to control in line flow and maintain bus voltages in desired level and so improve voltage profile and stability margins. This paper proposes a systematic method for finding optimal location of SVC to improve voltage profile of a power system. A contingency analysis to determine the critical outages with respect to voltage security is also examined in order to evaluate the effect of SVC on the location analysis. Effectiveness of the proposed method is demonstrated on IEEE 30-bus test system.

scholarly journals Grid-connected Response Verification of AC Microgrid under Single Line-to-ground Short Circuit

2019 ◽  
pp. 1-10
Author(s):  
Maruf A. Aminu
Keyword(s):  
Power Systems ◽  
Reactive Power ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Dynamic Responses ◽  
Single Line ◽  
Physical Systems ◽  
Short Circuits ◽  
Power System Performance ◽  
Grid Interconnection

In design of power systems, assumptions are made to model the physical systems. The assumptions may not sufficiently reflect the behavior of the system under normal and faulted conditions. Under short circuit conditions, system parameters vary significantly, particularly in microgrids with grid interconnection capabilities. This paper presents the result of validating the response of a microgrid which is capable of grid interconnection and islanding under voltage and reactive power control regimes. The microgrid is modeled to incorporate two wind turbines, each rated 5.5 kW, 400 V. The utility has synchronous generator rated 100 MW, 13.8 kV. Both the utility and microgrid are capable of exchanging active power and reactive power. Single line-to-ground short circuits are introduced and withdrawn at 30.00 s and 32.00 s, respectively. The dynamic responses of the testbed are captured pre-, during- and post-short circuit in grid-connected mode under both control regimes. The response of the testbed is verified to be consistent with established short circuit theory, verifying the validity of the system for short circuit detection and analysis. The testbed can therefore be used for short circuit and related studies, design optimization and power system performance prediction.

scholarly journals Load Flow Analysis in Hybrid AC-DC Transmission Network

2021 ◽  
pp. 617-624
Author(s):  
Ajith M ◽  
Dr. R. Rajeswari
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Power Flow ◽  
Reactive Power ◽  
Short Circuit ◽  
Flow Analysis ◽  
Load Flow ◽  
System Stability ◽  
And Control

Power-flow studies are of great significance in planning and designing the future expansion of power systems as well as in determining the best operation of existing systems. Technologies such as renewables and power electronics are aiding in power conversion and control, thus making the power system massive, complex, and dynamic. HVDC is being preferred due to limitations in HVAC such as reactive power loss, stability, current carrying capacity, operation and control. The HVDC system is being used for bulk power transmission over long distances with minimum losses using overhead transmission lines or submarine cable crossings. Recent years have witnessed an unprecedented growth in the number of the HVDC projects. Due to the vast size and inaccessibility of transmission systems, real time testing can prove to be difficult. Thus analyzing power system stability through computer modeling and simulation proves to be a viable solution in this case. The motivation of this project is to construct and analyze the load flow and short circuit behavior in an IEEE 14 bus power system with DC link using MATLAB software. This involves determining the parameters for converter transformer, rectifier, inverter and DC cable for modelling the DC link. The line chosen for incorporation of DC link is a weak bus. This project gives the results of load flow and along with comparison of reactive power flow, system losses, voltage in an AC and an AC-DC system.

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