scholarly journals Enhancement of Voltage Stability by Using SVC for 30-Bus Power System

2019 ◽  
Vol 4 (2) ◽  
pp. 128-136
Author(s):  
Dara Hama Amin

Voltage stability refers to maintaining the value of the voltage in all busses of the electric network at a steady level (initial operating point) during any sudden disturbance. Voltage instability may happen due to an increase in the demand of the load or in case of any change in the reactive power, thus, the system will go into uncontrollable and unstoppable decline in the voltage level. The effect of Static Var Compensator (SVC) on voltage stability is discussed in the paper, as well as the improvement of the voltage profile. Usually, SVC and FACTS devices were used for enhancing the voltage level profile and so the stability. Choosing the optimal location for the FACTS devices is essential due to its expensive costs. This paper used sensitivity factor to helpful to determine the most correct placement of FACTS devices in the system. Simulations are performed on Kurdistan Region 30-bus Power System using MATLAB-PSAT tool. As a result, the voltage of all 30 buses calculated. Based on the “voltage sensitivity factor”, the nominated weak buses has been marked which are suitable for placing the FACTS devices in order to improve the limits of the voltage stability of the system. Moreover, depending on the obtained optimal locations, a full analysis of the voltage and powers for the system has applied in two cases, before and after placing SVC respectively which is result in notable stability improvement and losses reduction.

2021 ◽  
Vol 18 (1) ◽  
pp. 63-69
Author(s):  
I.E. Nkan ◽  
E.E. Okpo ◽  
O.I. Okoro

Flexible alternating current transmission system (FACTS) devices have provided proficient answers to power system instabilities faced in the systems operations today with very little infrastructural investment fund. This paper investigates the effects of the installation of the combination of two kinds of FACTS controllers; static VAR compensator (SVC) and thyristor controlled series compensator (TCSC) compared with the installation of SVC or TCSC alone in the system. Voltage magnitude profile, active and reactive power losses of the three scenarios were achieved in the Nigerian 48-bus power system network using power system analysis toolbox (PSAT) in MATLAB environment. Simulation results obtained without and with FACTS devices optimally placed using voltage stability sensitivity factor (VSSF), revealed that the percentage decrease of the net real and reactive power losses of the combined SVC and TCSC was the highest at 31.917% whereas that of the standalone SVC and TCSC stood at 19.769% and 30.863% respectively. This shows that in addition to their capabilities to maintain acceptable voltage profile, the combination of SVC and TCSC has better compensating effect as they mitigate against power losses which was observed in their high percentage decrease in power losses compared to the standalone FACTS devices. Keywords: FACTS, optimum location, PSAT, SVC, TCSC, VSSF


2012 ◽  
Vol 61 (2) ◽  
pp. 239-250 ◽  
Author(s):  
M. Kumar ◽  
P. Renuga

Application of UPFC for enhancement of voltage profile and minimization of losses using Fast Voltage Stability Index (FVSI)Transmission line loss minimization in a power system is an important research issue and it can be achieved by means of reactive power compensation. The unscheduled increment of load in a power system has driven the system to experience stressed conditions. This phenomenon has also led to voltage profile depreciation below the acceptable secure limit. The significance and use of Flexible AC Transmission System (FACTS) devices and capacitor placement is in order to alleviate the voltage profile decay problem. The optimal value of compensating devices requires proper optimization technique, able to search the optimal solution with less computational burden. This paper presents a technique to provide simultaneous or individual controls of basic system parameter like transmission voltage, impedance and phase angle, thereby controlling the transmitted power using Unified Power Flow Controller (UPFC) based on Bacterial Foraging (BF) algorithm. Voltage stability level of the system is defined on the Fast Voltage Stability Index (FVSI) of the lines. The IEEE 14-bus system is used as the test system to demonstrate the applicability and efficiency of the proposed system. The test result showed that the location of UPFC improves the voltage profile and also minimize the real power loss.


2020 ◽  
Vol 1 (1) ◽  
pp. 26-30
Author(s):  
Violet Kaswii ◽  
Michael Juma Saulo

The interline power flow controller (IPFC) and the unified power flow controller (UPFC) are both advanced types of flexible AC transmission systems (FACTS). These devices can provide the power system with control of voltage, and that of real and reactive power. This paper reviews the literature on UPFC and IPFC FACTS devices in voltage control and covers two main areas of research (i) voltage control using FACTS devices, and (ii) UPFCs / IPFCs and their applications in power systems. FACTs devices are applied in modern power system networks for the purpose of voltage control while at the same time providing enhanced power system stability. Research has shown that their benefits in the long run outweighs their high cost especially when they are optimally sized and located in the power network. Moreover, in the planning of power transmission systems, a Multi-Criteria Decision Making (MCDM) technique can help in the incorporation of both the costs and technical viability. This approach provides techno-economic optimization and at the same time meeting environmental criteria.


Author(s):  
Mahmood Khalid Zarkani ◽  
Ahmed Sahib Tukkee ◽  
Mohammed Jasim Alali

<p>The rapid and enormous growths of the power electronics industries have made the flexible AC transmission system (FACTS) devices efficient and viable for utility application to increase power system operation controllability as well as flexibility. This research work presents the application of an evolutionary algorithm namely differential evolution (DE) approach to optimize the location and size of three main types of FACTS devices in order to minimize the power system losses as well as improving the network voltage profile. The utilized system has been reactively loaded beginning from the base to 150% and the system performance is analyzed with and without FACTS devices in order to confirm its importance within the power system. Thyristor controlled series capacitor (TCSC), unified power flow controller (UPFC) and static var compensator (SVC) are used in this research work to monitor the active and reactive power of the carried out system. The adopted algorithm has been examined on IEEE 30-bus test system. The obtained research findings are given with appropriate discussion and considered as quite encouraging that will be valuable in electrical grid restructuring.</p>


2018 ◽  
Vol 218 ◽  
pp. 01005 ◽  
Author(s):  
Rahman Yuli Asmi ◽  
Agus Siswanto ◽  
Irwan Mahmudi

Related to environmental issues resulting from the use of traditional energy sources, drive usage of renewable energy is increasing. Changes in the structure of the network will certainly affect the changes in voltage stability. In this paper, discuss the impact of the stability after distributed generation penetration whose its output intermittent relatively. The simulation based PSAT software and tested into IEEE 30 bus system. Observation of voltage deviation and SVSI-index on some load buses in conditions before and after integration of wind generation. Load condition is a very determining factor of bus voltage stability index. This relates to the active power and reactive power needs that must be injected by DG penetration.


2018 ◽  
Vol 7 (2.6) ◽  
pp. 199
Author(s):  
Balaji Venkateswaran V ◽  
Neeraj Kumar Sharma ◽  
Deepali Yadav

In recent days, the power system is incorporated with Flexible AC Transmission System (FACTS) devices for compensation of reactive power to maintain the stability of the system. The stability of the system is highly dependent on the state variables which are the outcomes of a state estimator in the power system. To improve the efficiency of a state estimator, high precision measuring devices such as Phasor Measurement Units (PMUs) are installed in the power system. Hence a state estimator embedded with these compensatory devices and PMUs is necessary for estimation of state variables. The present work has been carried out in three steps. Step 1: Considering the cost of PMUs and the availability of the communication network in the particular location, PMUs are optimally placed in the nodes of the system so that all critical measurements are transmuted into redundant ones using differential evolution (DE) algorithm to perform observability analysis. Step 2: A hybrid state estimation is performed by including the mathematical model of FACTS devices and PMUs. Step 3: It is shown that by installing optimal number of PMUs at desired location, multiple bad data detection and identification capability of residual method is considerably improved. Lastly, numerical simulation with standard IEEE 14 bus system, IEEE 118 bus system and a practical 246 bus system of northern region power grid (NRPG) is presented to confirm the effectiveness of the proposed approach in assessing the estimation of the system state variables.


2013 ◽  
Vol 62 (4) ◽  
pp. 541-552
Author(s):  
B. Bhattacharyya ◽  
Vikash Kumar Gupta ◽  
Sanjay Kumar

Abstract The problem of improving the voltage profile and reducing power loss in electrical networks must be solved in an optimal manner. This paper deals with comparative study of Genetic Algorithm (GA) and Differential Evolution (DE) based algorithm for the optimal allocation of multiple FACTS (Flexible AC Transmission System) devices in an interconnected power system for the economic operation as well as to enhance loadability of lines. Proper placement of FACTS devices like Static VAr Compensator (SVC), Thyristor Controlled Switched Capacitor (TCSC) and controlling reactive generations of the generators and transformer tap settings simultaneously improves the system performance greatly using the proposed approach. These GA & DE based methods are applied on standard IEEE 30 bus system. The system is reactively loaded starting from base to 200% of base load. FACTS devices are installed in the different locations of the power system and system performance is observed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. GA and DE based algorithm is then applied to find the amount of magnitudes of the FACTS devices. Finally the comparison between these two techniques for the placement of FACTS devices are presented.


Power system is a largely inter connected network, due to this interconnection some of the lines may get over loaded and voltage collapse will occur , hence these lines are called weak lines, this causes serious voltage instability at the particular lines of the power system. The improvement of stability will achieve by controlling the reactive power flow. The Flexible Alternating Current Transmission Systems (FACTS) devices have been proposed to effectively controlling the power flow in the lines and to regulate the bus voltages in electrical power systems, resulting in an increased power transfer capability, low system losses and improved stability. In FACTS devices the Unified Power Flow Controller (UPFC) is one of the most promising device for power flow control. It can either simultaneously or selectively control both real and reactive flow and bus voltage. UPFC is a combination of shunt and series compensating devices. Optimal location of UPFC is determined based on Voltage Stability Index (VSI). GA and PSO techniques are used to set the parameters of UPFC [6]. The objective function formulated here is fitness function, which has to be maximized for net saving. The results obtained using PSO on IEEE 14 Bus is compared with that of results obtained using GA, to show the validity of the proposed techniques and for comparison purposes


2011 ◽  
Vol 110-116 ◽  
pp. 5200-5205 ◽  
Author(s):  
J. Hamad ◽  
K. El-Bahrawy ◽  
R. Sharkawy

This paper investigates voltage stability of the power system during steady state and transient conditions. The voltage stability enhancement is achieved by utilizing FACTS devices at the best location of the system. The weakest bus in the system is the best location to implement shunt compensation device. In this paper, the weakest buses are identified via a fuzzy technique that utilizes two critical indices: Line Flow Index (LFI) and Voltage Profile Index (VPI) during normal and fault conditions. These indices are used to evaluate Criticality Index (CI) using Fuzzy rules, and thus, the system buses are ranked. Remedial actions are discussed to enhance the power system voltage stability by using FACTS devices (SVC and STATCOM) at the most vulnerable system buses. The results of this study show that the (STATCOM) performance is preferable to that of the (SVC) during fault conditions.


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