Location Of Unified Power Flow Controller Research Articles

Optimizing size and location of UPFC for enhanced system dynamic stability using hybrid approach

Optimizing size and location of UPFC for enhanced system dynamic stability using hybrid approach

OPTIMAL PLACEMENT OF UNIFIED POWER FLOW CONTROLLER USING PARTICLE SWARM OPTIMIZATION TECHNIQUE

The load growth in recent times due to advancements in technology and population increase has led to shortage of reactive power in the power system resulting in key issues such as voltage instability, large line losses, power outages among others. In this work, Particle Swarm Optimization (PSO) technique was used for optimal placement of Unified Power Flow Controller (UPFC) for power loss minimization using the IEEE 6-bus system as a test network. The load flow analysis was performed using Gauss-Seidel iterative method with and without inclusion of PSO-based UPFC. The PSO algorithm was used to find the optimum point for UPFC location and determined using the line with the least active power loss among other lines randomly selected by the PSO algorithm, with p.u defined as the voltage statutory limit. The simulation results revealed that the optimum point obtained was line 4-5, and the voltage profile were within the statutory limit with and without optimally placed UPFC. The total active power loss reduced from 495.5 to 273.9 MW, giving a reduction of 44.72 with optimally placed UPFC. The total reactive power loss equally reduced from 1439 to 936.2 MVAr, producing a reduction of 34.94 with optimally placed UPFC. These results obtained showed that PSO-based UPFC placement is suitable for power loss minimization and enhancement of the system voltage profile.

Sensitivity analysis index to determine the optimal location of multi-objective UPFC for improvement of power quality parameters

Sensitivity analysis index to determine the optimal location of multi-objective UPFC for improvement of power quality parameters

Loss reduction of transmission lines using PSO-based optimum performance of UPFC

Transmission line losses are one of the essential topics and issues in power systems research. Several methods and techniques have been used to reduce these losses, and one of these modern techniques is flexible alternating current transmission systems (FACTS). In this paper, one of the most important types of this technology, the unified power flow controller (UPFC), was used to reduce losses in the Iraqi national grid (ING) 400 kV. This paper presents an efficient method for minimizing losses of transmission lines in the ING system (400 kV) 46-bus approach. A particle swarm optimization (PSO)-based optimum proportional-integral (PI) controller with UPFC was proposed to obtain the optimal location of UPFC and optimum parameters of the PI controller to achieve the objective function of the research. MATLAB coded the algorithm. The Newton-Raphson method was employed to perform load flow analysis. The results showed that the best place for UPFC is buses (14-17) named BGE4 (Baghdad)-AMN4 (Baghdad), and the total active power and reactive power losses decreased from 727.4593 to 579.3874 MW and from 5155.9 to 3971.1 MVAR, respectively and also led to voltage regulation.

Application of whale algorithm optimizer for unified power flow controller optimization with consideration of renewable energy sources uncertainty

Purpose. In this paper an allocation methodology of Flexible Alternating Current Transmission Systems (FACTS) controllers, more specifically, the Unified Power Flow Controller (UPFC) is proposed. As the penetration of Renewable Energy Sources (RESs) into the conventional electric grid increases, its effect on this location must be investigated. Research studies have shown that the uncertainty of RESs in power generation influences the reactive power of a power system network and consequently its overall transmission losses. The novelty of the proposed work consists in the improvement of voltage profile and the minimization of active power loss by considering renewable energy sources intermittency in the network via optimal location of UPFC device. The allocation strategy associates the steady-state analysis of the electrical network, with the location and adjustment of controller parameters using the Whale Optimization Algorithm (WOA) technique. Methodology. In order to determine the location of UPFC, approaches are proposed based on identification of a line which is the most sensitive and effective with respect to voltage security enhancement, congestion alleviation as well as direct optimization approach. The optimum location of UPFC in the power system is discussed in this paper using line loading index, line stability index and optimization method. The objective function is solved using the WOA algorithm and its performance is evaluated by comparison with Particle Swarm Optimization (PSO) algorithm. Results. The effectiveness of the proposed allocation methodology is verified through the analysis of simulations performed on standard IEEE 30 bus test system considering different load conditions. The obtained results demonstrate that feasible and effective solutions are obtained using the proposed approach and can be used to overcome the optimum location issue. Additionally, the results show that when UPFC device is strategically positioned in the electrical network and uncertainty of RES is considered, there is a significant influence on the overall transmission loss and voltage profile enhancements of the network.

Optimal location of UPFC based on sensitivity of CDF with power system’s stochasticity

In this paper, a stochastic sensitivity algorithm is introduced to optimize the location of unified power flow controller (UPFC) in large scale power grid. The stochastic sensitivities are defined as the total operation cost of power system to control parameters of UPFC. Firstly, probability optimal power flow (POPF) model with power system’s randomness is established. Then point estimate method (PEM) is utilized to solve the above problem, so that the stochastic sensitivities of UPFC in all possible transmission lines could be obtained. Finally, by sorting the influence degree of UPFC at different locations to cumulative distribution function (CDF) of operation cost, the optimal location for UPFC could be selected correspondingly. To this end, IEEE-5 and IEEE-14 systems are employed to verify our proposed approach. The results show that installing UPFC by the method in this paper could significantly reduce the probability distribution of operation cost in higher region.

Voltage Stability Improvement with finest position of UPFC using GA &PSO

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

Enhancement of voltage stability in an interconnected network using unified power flow controller

In this paper, the optimal placement of Unified Power Flow Controllers (UPFC) in a large-scale transmission network in order to improve the loadability margin was considered. In other to achieve this aim, the Line Stability Factor (LQP) as a technique for the optimal location of UPFC in the IEEE 14-bus network and 56-bus Nigerian national grid was adopted. The power injection model for the UPFC was employed to secure improvements in the loading margin of the IEEE 14-bus network and 56-bus Nigerian national grid system. Continuation power flow was used to assess the effect of UPFC on the loadability margin. Steady-state simulations using Power System Analysis Toolbox (PSAT) on MATLAB was applied to determine the effectiveness of placing UPFC between bus 13 and bus 14 in the IEEE 14-bus network and between bus 44 (Ikot-Ekpene) and bus 56 (Odukpani) in the 56-bus Nigerian national grid system. The results showed that the loadability margin increased by 8.52 % after UPFC was optimally placed in the IEEE 14-bus network and increased by 195.5 % after UPFC was optimally placed in the 56-bus Nigerian national grid system. Thus, these enhance the voltage stability of both network and utilizing the network efficiently.

Optimal Allocation of UPFC to Minimize Real Power Losses using Firefly Algorithm

Reducing the loss of real power and maintaining the system voltage under limits are challenging and major problems in a power system network. Thus, it is desired to adapt an effective method that could clear up these problems or reduce it to the minimal level. Controllers with FACTS, for instance Unified Power Flow Controller (UPFC) can effectively enhance the various power system parameters. This paper proposes a new meta-heuristic algorithm known as firefly algorithm (FA) which is used to select the optimal location and sizing of UPFC , which minimizes the total real power losses and to maintain the voltage under limits, there by maintaining the power system stability. On the IEEE 14 bus system the performance of the proposed method is examined by taking into account the 125%, 150%, 175% and 200% overloading cases.

Optimal location and sizing of UPFC for optimal power flow in a deregulated power system using a hybrid algorithm

A hybrid algorithm for power system multi-area multi-fuel economic-emission dispatch, using a unified power flow controller (UPFC), is presented in this paper. The proposed algorithm is a combination of both integrated ant-lion optimiser (IALO) and grasshopper optimisation algorithm (GOA) called IALGOA. The integrated crossover and mutation techniques enhance the searching behaviour of ALO. The IALO approach is used to identify UPFC optimal location based on the objective function for the economic dispatch. Furthermore, the GOA approach is used to determine the UPFC optimal capacity based on its dependent parameters. Therefore, the proposed method can be easily applied to optimise the power system objectives while considering the operational constraints of the available generation resources, practical constraints and device limits. The proposed IALGOA technique is implemented using MATLAB/Simulink and the performance is tested with the IEEE standard 30-bus system. To evaluate the performance of the proposed IALGOA technique, it is compared with Existing techniques such as artificial bee colony-gravitational search algorithm and fire-fly-cuckoo search. The effectiveness of the proposed IALGOA technique is evaluated using the simulation results.

Enhancement of dynamic stability by optimal location and capacity of UPFC: A hybrid approach

Abstract In the paper, the modified salp swarm optimization algorithm (MSSA) and moth-flame optimization algorithm (MFO) based optimal location and capacity of Unified Power Flow Controller (UPFC) to improve the dynamic stability of the power system is proposed. The novelty of the proposed method is exemplified in the improved searching ability, random reduction and reduced complexity. Here, the MSSA is used to optimize the location of the UPFC while the generator fault occurs. The MSSA selects the maximum power loss line as the optimum location to place UPFC as per the objective function, since the generator fault violates the system equality and inequality constraints from the secure limit. From the UPFC control parameters, the minimum voltage deviation is optimized using the MFO algorithm. The minimum voltage deviation has been used to find the optimum capacity of the UPFC. Then the optimum UPFC capacity is applied in the optimum location, which enhances the dynamic stability of the system. The proposed method is implemented in the MATLAB/Simulink platform and the performance is evaluated by means of comparison with the different techniques like GSA-BAT, MFO-FF, SSO-FF, BAT-FF and CS-FF algorithms. The comparison results demonstrate the superiority of the proposed approach and confirm its potential to solve the problem.

Optimal Location and Parameter Settings of UPFC Using ACO for Enhancing Power System Security under Single Contingencies

Optimal setting and location of Flexible AC Transmission Systems (FACTS) devices are widely used in enhancing power system security. The most effective FACTS device is Unified Power Flow Controller (UPFC) which has both series and shunt compensation. The effectiveness of FACTS device over the mitigation of security issues depends on its location and its parameter settings. Hence, this paper presents Ant Colony Optimization (ACO) methodology to optimally locate UPFC to enhance power system security under single contingencies (N-1 Contingency). The simulation is carried out on IEEE 6 bus and IEEE 14 bus test systems considering line over loads and bus voltage violations for ensuring system security. This approach is twofold. Initially, an N-1 contingency test is performed based on severity ranking is done then UPFC is placed optimally using ACO algorithm to mitigate the severity. Further to validate the proposed approach the results are compared with the conventional Non Linear Programming – Interior Point (NLP-IP) technique.

A critical fault detection analysis & fault time in a UPFC transmission line

This paper discusses a critical study of fault detection and fault time analysis in a Unified Power Flow Controller (UPFC) transmission line. Here the Discrete Wavelet Transform (DWT) and Discrete Fourier Transform (DFT) approach are used for processing the faulty current signal to obtain fundamental current signal. The extracted fault current signals from the current transformer are fed to DWT and DFT approach for computing spectral energy (SE). The differential spectral energy (DSE) of phase currents are evaluated by taking the difference of SE obtained at sending and receiving end. The DSE is the key factor for deciding the fault in any of the phase or not. The Daubechy mother wavelet (db4) is used here because of its high accuracy of detection with less processing time. The novelty of the scheme is that it can accurately detect the critical fault variation of the line. Number of simulations are validated at the extreme condition of the line and compared to other conventional existing scheme. Multi-phase fault in double circuit line, CT saturation, UPFC operating condition (series voltage and angle), UPFC location and wind speed variation including wind farm simulation are validated to verify the performance of the scheme. The advantages of the scheme is that it works effectively to detect the fault at any stage of critical condition of the line and fault detection time remains within 20 msec (less than one cycle period). This scheme protects both internal and external zone including parameter variation of the line.

Implementation Optimal Location and Sizing of UPFC on Iraqi Power System Grid (132 kV) Using Genetic Algorithm

Electric power systems required efficient processors and intelligent methods for sustainability therefore, in this paper used Flexible AC Transmission System (FACTS) device specifically Unified Power Flow Controller (UPFC) because of its useful properties on series and shunt devices and used Genetic Algorithm (GA) to determine the optimal location and values of UPFC to achieve the following objectives: improve voltages profile, reduce power losses, treatment of power flow in overloaded transmission lines and reduce power generation. Consequently, all of these goals led to a reduction in the total cost of the power system. GA was applied to an Iraqi local power grid system (Diyala 132 kV) to find the optimal values and locations of UPFC for the purpose of achieving the objectives mentioned above using the MATLAB program. The simulation results showed the effectiveness of GA to calculate the optimum values and locations of UPFC and promising results were obtained for the Diyala power network (132 kV) with regard to the desired objectives.

A PSO based search for optimal tuning and fixing of UPFC to improve usefulness of distribution system

With socio-economical development, power distribution systems are forced to work with both heavy as well as light loads, which causes voltage instability and power loss. This paper develops a Particle Swarm Optimization (PSO) based algorithm to find an optimal place and parameter of Unified Power F low Controller (UPFC) to improve voltage profile with minimum system loss. UPFC is a most versatile Flexible Alternating Current Transmission System (FACTS) controller, which can control bus voltage; flow of active as well as reactive power through lines. The novelty of this work is to fix the location of UPFC at base load to make power distribution system more secure and efficient, by tuning its parameters at all possible load conditions. The developed methodology is employed in IEEE 30-bus system with different intensities of the load. Results prove the success of developed technique and verify the potential of UPFC for improvement of system stability with mitigation of losses.

New Approach for Optimal Location and Parameters Setting of UPFC for Enhancing Power Systems Stability under Contingency Analysis

Operation of power system within specified limits of voltage and frequency are the major concerns in power system stability studies. As power system is always prone to disturbances, which consequently affect the voltage instability and optimal power flow, and therefore risks the power systems stability and security. In this paper, a novel technique based on the “Artificial Algae Algorithm” (AAA) is introduced, to identify the optimal location and the parameters setting of Unified Power Flow Controller (UPFC) under N-1 contingency criterion. In the first part, we have carried out a contingency operation and ranking process for the most parlous lines outage contingencies while taking the transmission lines overloading (NOLL) and voltage violation of buses (NVVB) as a performance parameter (PP = NOLL + NVVB). As UPFC possesses too much prohibitive cost and larger size, its optimal location and size must be identified before the actual deployment. In the second part, we have applied a novel AAA technique to identify the optimal location and parameters setting of UPFC under the discovered contingencies. The simulations have been executed on IEEE 14 bus and 30 bus networks. The results reveals that the location of UPFC is significantly optimized using AAA technique, which has improved the stability and security of the power system by curtailing the overloaded transmission lines and limiting the voltage violations of buses.

Optimal robust stabilizer design based on UPFC for interconnected power systems considering time delay

AbstractA robust auxiliary wide area damping controller is proposed for a unified power flow controller (UPFC). The mixedH2/H∞problem with regional pole placement, resolved by linear matrix inequality (LMI), is applied for controller design. Based on modal analysis, the optimal wide area input signals for the controller are selected. The time delay of input signals, due to electrical distance from the UPFC location is taken into account in the design procedure. The proposed controller is applied to a multi-machine interconnected power system from the IRAN power grid. It is shown that the both transient and dynamic stability are significantly improved despite different disturbances and loading conditions.

Load Curtailment Sensitivity Indices Through Optimal Placement of Unified Power Flow Controller

The optimal power flow (OPF) is one of the key tasks to be performed in the complicated operation and planning of a power system. Directing the power in such a way that the lightly loaded branches are loaded to reduce the system load curtailment is an option which can be achieved by making use of FACTS devices. This paper proposes a set of load curtailment sensitivity indices for optimal placement of Unified Power Flow Controller (UPFC) in power system network. An OPF formulation considering the minimization of load curtailment requirement as an objective has been developed in this paper to study the impact of optimal placement of UPFC. The effectiveness of the proposed method has been tested on IEEE-14 bus test system. The obtained results have been presented in terms of change in system load curtailment with respect to changes in UPFC controller parameters for the best location. The optimal location of UPFC in a line has been decided based on the calculated sensitivity indices. Conclusion is made on different results to see the benefit of UPFC in power system.

Line Stability Index Based Optimal Placement of Unified Power Flow Controller

Unified power flow controller (UPFC) is a powerful device which can control three power system parameters and it must be located optimally to obtain satisfactory performance due to excessive cost. This paper presents an approach to find the optimal placement of UPFC based on the line stability index. The line stability index can provide accurate information of the stability condition of the lines of the system and can also determine the weakest bus in the system. The index is evaluated for partial network of Myanmar National grid transmission network using MATPOWER Toolbox and a line having largest value of the index is the most critical line where the optimal location of UPFC. The proposed placement approach is shown to be effective for finding appropriate location of UPFC and the effects of UPFC allocation based on line stability index are also demonstrated using Power System Analysis Toolbox (PSAT). The optimal placement of UPFC based on the line stability index resulted in enhancing the power flow control of the system, reducing the system losses as well as improving the system voltage profile.

Congestion mitigation using UPFC

Transmission congestion is one of the most challenging issues in operation of deregulated electricity markets of today. This study investigates into benefit of unified power flow controller (UPFC) as a viable solution to the problem of congestion management. A comprehensive load flow model for the UPFC is presented which has the capability to control active and reactive powers and voltage magnitude simultaneously. This study discusses about two different approaches for determination of suitable location of UPFC. One of them is sensitivity-based approach and the other is pricing-based method. Reduction in total system losses has been taken as objective in sensitivity-based approach. Furthermore, sensitivity of total system losses with respect to control parameters of UPFC have been evaluated using two different methods. A pricing-based approach which makes use of locational marginal price difference and congestion rent for determination of suitable location of UPFC. Minimisation of cost of rescheduling subjected to system operating constraints is the objective to be met for congestion management. Interior point method, a mathematical tool for non-linear optimisation, is used to obtain the solution of above-mentioned problem.