scholarly journals Raise Voltage Stability Limit of a Power System using Reactive Power Compensation Technique

In recent years, voltage stability problems have been increasing since power systems operate close to stability limits. The voltage stability problem of a power system is associated with a rapid voltage drop due to heavy system load and it occurs because of inadequate reactive power support at some critical bus. One of the serious consequences of the voltage stability is a system blackout, and this has received more attention in recent years. Accurate determination of stability limit and amount of reactive power injection to stabilize is important.This paper proposes to determine voltage stability margin of a critical bus and also provide amount of reactive power injection to the bus particularly during overload, a simple two bus equivalent model of the power system is used to determine the maximum apparent power for different power factors. Any required apparent power can directly obtained by correcting the reactive power at critical bus. Experimental results support our theoretical findings.

Author(s):  
Raja Masood Larik ◽  
Mohd. Wazir Mustafa ◽  
Manoj Kumar Panjwani

<p>Despite a tremendous development in optimal power flow (OPF), owing to the obvious complexity, non-linearity and unwieldy size of the large interconnected power systems, several problems remain unanswered in the existing methods of OPF. Seizing specific topics for maximizing voltage stability margin and its implementation, a detailed literature survey discussing the existing methods of solution and their drawbacks is presented in this research. The phenomenon of voltage collapse in power systems, methods to investigate voltage collapse, and methods related to voltage stability are briefly surveyed. Finally, the study presents a statistical method for analyzing a power system through eigenvalue analysis in relation to the singular values of the load flow Jacobian. Future study may focus on changes in theories in conjunction with large power systems.</p>


2021 ◽  
Author(s):  
Umang Patel

Power system stability is gaining importance because of unusual growth in power system. Day by day use of nonlinear load and other power electronics devices created distortions in the system which creates problems of voltage instability. Voltage stability of system is major concerns in power system stability. When a transmission network is operated near to their voltage stability limit it is difficult to control active-reactive power of the system. Our objectives are the analysis of voltage stability margin and active-reactive power control in proposed system which includes model of STATCOM with aim to analyse its behavior to improve voltage stability margin and active-reactive power control of the system under unbalanced condition. The study has been carried out using MATLAB Simulation program on three phase system connected to unbalanced three phase load via long transmission network and results of voltage and active-reactive power are presented. In future work, we can do power flow calculation of large power system network and find the weakest bus of the system and by placing STATCOM at that bus we can improve over all stability of the system


Nowadays, many countries have started to implement and installed solar photovoltaic (PV). The initial designs of existing power systems were not integrating with any renewable energy (RE) including PV. So, the small scale PV may not have any effect on these power systems. However, integrating large scale PV might raise several power quality issues including power system stability. Power system stability has become major attention where the main focus is on voltage stability.Voltage stability is related on electrical grid capacity to balance the Total Power of Demand (PD) and Total Power generated by Generator (Pgtt). Instability of the voltage can cause inability of the power system to meet the demand of reactive power. The lack of reactive power will cause instability in the power system.This paper present optimal placement and sizing of PV for stability enhancement and operating cost minimization. In this research, reactive power has gradually increased and Fast Voltage Stability Index (FVSI) is applied to analyze voltage stability. PV is applied to stabilize voltage stability of the power system. Economic Load Dispatch (ELD) is conducted to determine the optimal cost and loss. DEIANT is conducted to optimize the total cost and the total loss after solar PV implementation. Simulation result indicates the effectiveness of the proposed technique for stability enhancement and operating cost minimization.


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


Author(s):  
Mohammed Amroune ◽  
Tarek Bouktir ◽  
Ismail Musirin

AbstractIn recent years, due to the economic and environmental issues, modern power systems often operate proximately to the technical restraints enlarging the probable level of instability risks. Hence, efficient methods for voltage instability prevention are of great importance to power system companies to avoid the risk of large blackouts. In this paper, an event-driven emergency demand response (EEDR) strategy based on whale optimization algorithm (WOA) is proposed to effectively improve system voltage stability. The main objective of the proposed EEDR approach is to maintain voltage stability margin (VSM) in an acceptable range during emergency situations by driving the operating condition of the power system away from the insecure points. The optimal locations and amounts of load reductions have been determined using WOA algorithm. To test the feasibility and the efficiency of the proposed method, simulation studies are carried out on the IEEE 14-bus and real Algerian 114-bus power systems.


2014 ◽  
Vol 960-961 ◽  
pp. 1124-1127
Author(s):  
Si Yu Li ◽  
Jia Dong Huang ◽  
Cui Ma

Nowadays, unbalanced loads or nonlinear loads produce a bad effect on the power quality of utility mains. Also, it is necessary for reactive power to be compensated because the most of industrial loads is inductive and make a lagging displacement power factor. Reactive power compensation utilizing STATCOM is one of the most important methods to improve power quality. In this paper, the technical feature of STATCOM is introduced and then a comparison with SVC is made. The effect of STATCOM on static voltage stability in power systems has been studied. Based on PSD-BPA software, effect of STATCOM is determined. Static voltage stability margin enhancement using STATCOM and SVC is compared in the modified IEEE 14-bus test system. Test results show very encouraging result.


Author(s):  
R. KALAIVANI ◽  
V. KAMARAJ

Due to huge increase in power demand, modern power system networks are being operated under highly stressed conditions. This has resulted into the difficulty in meeting reactive power requirement and maintaining the bus voltage within acceptable limits. Voltage instability in the system occurs in the form of a progressive decay in voltage magnitude at some of the buses. The problems of voltage instability and voltage collapse are the major concerns in the operation of power system. It is very important to do the power system analysis with respect to voltage stability. Flexible AC Transmission System (FACTS) device in a power system improves the stability, enhances the voltage stability margin and reduces the power losses. Identification of location of FACTS device in the power system is very important task. Research is carried out to investigate application of Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and hybrid PSOGA to find optimal location and rated value of SVC device to minimize the voltage stability index, total power loss, load voltage deviation, cost of generation and cost of FACTS device to improve voltage stability in the power system. Optimal location and rated value of SVC device have been found for different loading scenario using PSO, GA and PSOGA. It is observed from the results that the voltages stability margin is improved, voltage profile of the power system is increased, load voltage deviation is reduced and real power losses also reduced by optimally locating SVC device in the power system. The proposed algorithm is verified with IEEE 14 bus and 30 bus power systems.


2021 ◽  
Vol 16 (3) ◽  
pp. 245-250
Author(s):  
Giulio Lorenzini ◽  
Mehrdad Ahmadi Kamarposhti ◽  
Ahmed Amin Ahmed Solyman

Current methods to determine the wind farms maximum size do not consider the effect of new wind generation on the Voltage Stability Margins (VSMs). Installing wind power in one area may affect VSMs in other areas of the power system. Buses with high VSMs before wind power injection may be converted into weak buses after wind power injections in other parts of power systems, which may lead to limited future wind farms expansion in other areas. In this paper, two methods are proposed to determine two new wind farms maximum size in order to maximize wind power penetration level. In both methods, the size of any new wind farm is determined using an iterative process which is increased by a constant value. Proposed methods were used in the IEEE 14-bus power system. The results of applying these new methods indicate that the second method results in higher maximum sizes than the first method.


2012 ◽  
Vol 433-440 ◽  
pp. 1794-1801 ◽  
Author(s):  
Jian Dong Duan ◽  
Rui Li ◽  
Lin An

Squirrel-cage induction generator (SCIG), as its structural and economic advantages, has been widely utilized in large wind farms in China. However, the large wind farm composed of induction generators will cause obvious problems to the power system stability due to the dependency on reactive power. At the same time, Doubly-fed induction generator (DFIG), as a new type of wind turbine generator, has excellent dynamic characteristics for operation of wind farms. With the increase in penetration of wind power in power systems, more and more wind farms will use both SCIG and DFIG. In this case, the dynamic characteristic of wind farm on power systems is becoming an important issue especially in terms of the voltage stability. This article is to show by means of simulations the dynamic performance of wind farm linked to power system under the circumstances of network disturbances. Furthermore, the interaction between the SCIGs and DFIGs has also been investigated. A detailed model of wind farms is presented through the plat root of MATLAB/SIMULINK. The simulation results demonstrate that the DFIG applications will largely improve the dynamic performance of wind farm in certain conditions, if the DFIGs could be applied reasonably, the voltage stability of the wind farm will be largely improved and even low voltage ride through(LVRT) characteristic of SCIGs, which may be a good solution to reduce the high dependence of costly reactive power compensation equipment(Some flexible AC transmission systems devices like SVC, STATCOM) to some extent.


Sign in / Sign up

Export Citation Format

Share Document