Line Power Flow Research Articles

MATLAB SIMULATION OF D-STATCOM USING SVPWM

In this paper, A Distribution Static Synchronous Compensator (D-STATCOM) is used for improving the power factor, power quality and to control power flow control in the distribution line. It used to give reactive and active power compensation in the distribution line. The power depends on the power factor of the loads connected to the transmission line. In this paper we have used a new DSTATCOM using modified SVPWM technique. The previous DSTATCOM are basically controlled by PWM, or SPWM technique which produce high harmonics distortion but using SVPWM technique distortion reduces to maximum possible level. In our system we also have examined the losses due to DSTATCOM when connected in the distribution system. To decrease the reactive power and to minimize the undesirable load to require maintains the flow of reactive power. As a result, the power a factor of the load descant, leading to the limitation of the active power flow in the line. The D-STATCOM is a power electronics based on advanced device can be used to control power flow in the distribution line. The construction of system is able to recover the drop-in bus voltage when any loading effect arises, but due to 5th harmonic performance of DSTATCOM reduces somewhere.

GA Technique to Solve the AGC Problem of Thermal Generating Unit

In a large-scale power system, Automatic Generation Control (AGC) is responsible to area load changes and abnormal imprecise system operating parameters essentially means very fast minimization of area frequency deviations and mutual tie line power flow deviations of the areas for satisfactory and stable operation of the system. Some technique gives the good results in normal operation but in abnormal condition, it take large time to settle down the load disturbance, which is harmful for the system. New approach (Genetic Algorithm (GA) Technique) provides better control performance over frequency deviations and tie line power flow deviations due to a normal and abnormal operating condition of sudden load changes. In this paper six area model of thermal generating units has been developed and simulated in MATLAB Simulink software. Response of the developed model has been obtained by GA technique and compared with the other technique like; fuzzy, PID. Tabulated result shows that the GA technique give the better performance over the other technique due to settle down the frequency and tie line power flow deviations in less time and maintain the system constancy.

A hybrid algorithm based optimal placement of DG units for loss reduction in the distribution system

Distributed generation (DG) has been utilized in some electric power networks. Power loss reduction, environmental friendliness, voltage improvement, postponement of system upgrading, and increasing reliability are some advantages of DG-unit application This paper uses a hybrid technique to optimize the position and size of DG units to reduce losses in the distribution system. The hybrid technique is the joined execution of both the Grasshopper Optimization Algorithm (GOA) and Cuckoo Search (CS) technique. Here, the GOA optimization behavior is upgraded by utilizing the CS technique. Here, the perfect position of the DG unit is settled with respect to the power loss, line power flow and voltage profile using the proposed system. For improving the dynamic execution, the limit of DG is directed by the proposed technique with respect to the cost work. The motivation behind the proposed system is to produce optimal capacity to lessen the aggregate power loss and enhance the voltage profiles of power distribution networks. The proposed hybrid technique is executed in MATLAB/Simulink working platform and the dynamic dependability execution is tested and considered with IEEE 33-bus distribution networks and IEEE 69-bus system. The stability by diminishing loss of the distribution system is investigated by executed different load state of the system. The execution of the proposed system is analyzed and compared with different existing techniques.

Optimal Allocation of UPFC and IPFC in Network Considering Sensitivity of Line Flows under Single Line Contingency

This paper presents, optimal location for deployment of Unified Power Flow Controller (UPFC) and Interline Power Flow Controller (IPFC) in network considering sensitivity of line flows under single contingency. A sensitive approach is proposed which is considered based on Ranking Index (RI) and Performance Index (PI). A unitary change of power flow (PF) in each transmission line after outage of a branch element can be obtained from proposed index. The proposed Index is used to quantify loading level of network after a given outage. Contingencies are structured in descending order depending on value of proposed Index. Sensitivity factors are obtained by differentiating PF indices subject to parameters of UPFC and IPFC devices. Optimal deployment of UPFC and IPFC device is considered by the value of sensitivity factors attained by considering line outages in order of their severities which is given by proposed Index. The efficacy of proposed approach is computed and programmed on 5bus and IEEE 14bus networks under MATLAB environment.

Decentralized Voltage Control of PowerSystems Using Multi-agent Systems

A comprehensive scheme based on decentralized control, partitioning, multi-agent systems, and fuzzy logic is presented in this paper for the voltage control of power systems. In our proposed smart self-healing method, two types of control agents are defined, namely master and local, which are applied in two steps. In the first step, the power system returns to the normal state after fault occurrence. Immediately after a fault detection in a power system, the system is divided into three subsystems using spectral graph partitioning. Partitioning is conducted based on reactive power flow in transmission lines. For each subsystem, a local control agent and a performance index (PI) are defined. Whenever the PI of a subsystem exceeds its threshold limit, the local control agent uses the Sugeno fuzzy system to intelligently select and apply control actions. In the second step as performed by the master control agent, the power system is transformed to an optimal state by solving the optimization problem. Simulations on a 39-bus New England reveal the effective performance of the proposed method.

A Probabilistic Cascading Failure Model for Dynamic Operating Conditions

Failure propagation in power systems, and the possibility of becoming a cascading event, depend significantly on power system operating conditions. To make informed operating decisions that aim at preventing cascading failures, it is crucial to know the most probable failures based on operating conditions that are close to real-time conditions. In this paper, this need is addressed by developing a cascading failure model that is adaptive to different operating conditions and can quantify the impact of failed grid components on other components. With a three-step approach, the developed model enables predicting potential sequence of failures in a cascading failure, given system operating conditions. First, the interactions between system components under various operating conditions are quantified using the data collected offline, from a simulation-based failure model. Next, given measured line power flows, the most probable interactions corresponding to the system operating conditions are identified. Finally, these interactions are used to predict potential sequence of failures with a propagation tree model. The performance of the developed model under a specific operating condition is evaluated on both IEEE 30-bus and Illinois 200-bus systems, using various evaluation metrics such as Jaccard coefficient, F 1 score, Precision@K, and Kendall's tau.

Adaptive Unified Differential Evolution Algorithm for Optimal Operation of Power Systems with Static Security, Transient Stability and SSSC Device

The environmental degradation and increased power demand has forced modern power systems to operate at the closest stability boundaries. Thereby, the power systems operations mainly focus for the inclusion of transient stability constraints in an optimal power flow (OPF) problem. Algebraic and differential equations are including in non-linear optimization problems formed by the transient stability constrained based OPF problem (TSCOPF). Notably, for a small to large power systems solving these non-linear optimization problems is a complex task. In order to achieve the increased power carrying capacity by a power line, the Flexible AC transmission systems (FACTS) devices provides the best supported means a lot. As a result, even under a network contingency condition, the security of the power system is also highly improved with FACTS devices. The FACTS technology has the potential in controlling the routing of the line power flows and the capability of interconnecting networks making the possibility of trading energy between distant agents. This paper presents a new evolutionary algorithm for solving TSCOPF problems with a FACTS device namely adaptive unified differential evolution (AuDE). The large non-convex and nonlinear problems are solved for achieving global optimal solutions using a new evolutionary algorithm called AuDE. Numerical tests on the IEEE 30-bus 6-generator, and IEEE New England 10-generator, 39-bus system have shown the robustness and effectiveness of the proposed AuDE approach for solving TSCOPF in the presence of a FACTS device such as the SSSC device. Due to the page limitation only 30-bus results are presented.

Optimal V2G and Route Scheduling of Mobile Energy Storage Devices Using a Linear Transit Model to Reduce Electricity and Transportation Energy Losses

Mobile energy storage devices (MESDs) operate as medium- or large-sized batteries that can be loaded onto electric trucks and connected to charging stations to provide various ancillary services for distribution grids. This article proposes a new strategy for MESD operation, in which their power outputs and paths are co-optimally scheduled to minimize the total energy loss in both power and transportation networks. The distances moved by MESDs and time at different locations are modeled using a set of linear equations, considering the time-varying traffic flow. The linear transit model is integrated with linearized constraints to support the reliable operation of the distribution grid. In particular, an optimal scheduling problem is formulated considering the maximum limits on incremental variations in bus voltages and line power flows for active and reactive power outputs of MESDs. A mixed-integer linear programming solver can be readily applied to the optimization problem, ensuring the global optimality of the solution. Simulation case studies are carried out under various power and transportation network conditions. The results of these case studies confirm that the proposed strategy using MESDs is effective in reducing total energy losses, compared to conventional methods using stationary batteries and plug-in electric vehicles.

Model-Free Optimal Voltage Phasor Regulation in Unbalanced Distribution Systems

The proliferation of voltage Phasor Measurement Units (PMUs) into electric power distribution grids presents new opportunities for utility operators to manage their systems more effectively. In particular, distribution-level PMUs can serve as proxy measurements for active and reactive power flows, thus alleviating the need for current transformer-based measurements for certain applications. In this work, we explore the use of distribution PMU measurements to optimally control line power flows without explicit measurements of these quantities and without a priori knowledge of the underlying distribution system topology. To do so, we extend a 2 dimensional Extremum Seeking (2D-ES) control paradigm to simultaneously manage Distributed Energy Resource (DER) active and reactive power contributions in unbalanced distribution systems. Simulation results show the ability of the proposed approach to virtually island different portions of a 3-phase unbalanced the network using DER injections while maintaining proper voltage magnitudes in the rest of the network.

Online Kron Reduction for Economical Frequency Control of Microgrids

In this article, a distributed switched control system is proposed, which aims at frequency regulation and total generation cost minimization within a droop-based microgrid considering generator and line power constraints. The minimization is solved with the Lagrange method and is achieved by realizing the equal incremental cost criterion via a consensus algorithm. An online network reconfiguration is also proposed, which bypasses a distributed generator when it violates the generation limits or gets disconnected, or when its corresponding line power flow exceeds its upper limit. It is mathematically probed that the proposed reconfiguration is a distributed online Kron reduction, which leads to a new reduced data network; it preserves the existing spanning trees from cutting when a distributed generator is bypassed. Equilibrium analyses are conducted to show that the proposed switched system converges to the desired steady state. The stability of the system based on common quadratic Lyapunov function is discussed. The effectiveness of the proposed controller for different case studies is verified by adapting it to a test microgrid system.

Experimental Research on Performance Analysis of a UPFC Damping Controller

The unified power quality conditioner is equipment used for regulated voltage distortion and voltage unbalance in a power system. This device gives unique control on the power flow and voltage stability in the transmission line within their limits and enhancing the power to flow through the preferred path. This paper presents a control scheme and Theoretical derivation of the unified power flow conditioner and the simulation results are compared and contrasted in detail. UPFC is a combination of shunt Active and series active power filters. UPFC contains a DC link capacitor in a single phase voltage source inverter with two back to back connected, three-phase three-wire and three-phase four-wire are arranged. The objective of the study is to introduce a scheme which improves the quality of power in the flexible AC transmission systems on the aspects of voltage sag and harmonic distortion apart from enhancing power transfer capability and stability limit using unified power flow conditioner In this, the power system simulation models are made on MATLAB version. The results obtained show that the UPFC controller had better performance to damp LFO compared to the other UPFC damping controllers.

Power System Security by FACTS Devices using GA

Now daily's electrical power necessity has expanded exponentially while the development and rebuilding of the electrical power framework for age and transmission in the power segment has been basically restricted because of present assets and natural conditions. Accordingly, roughly of the halls of power transmission overhead lines are intensely stacked and clogged. Additionally the serious issue of power framework voltage dependability turns into a power move constraining and capacity factor. A Modern power electronics innovation FATCS based gadget Static Synchronous Series Compensator (SSSC) is a VSC based series FACTS gadget. Bound together power flow controller (UPFC) is to control power flow, voltage magnitude, and phase point. In this examination paper proposed to keep up the voltage magnitude just as power flow of broken lines. The result of change of the power framework parameters, for example, voltage, phase point, dynamic power, responsive power, and in general power factor with and without SSSC and UPFC have additionally been consolidated. Assessment of power framework security is important in the public arena to create approaches to keep up framework activity when at least one segments come up short. A power framework is "secure" when it can resist the loss of at least one fixings and still continue working without serious issues. The Contingency occasion examination strategy is taken to recognize electrical hub power flow in the flawed transmission lines. The Performance of power framework is checked on IEEE 14-Bus System.

Transmission system regularization with 5-level cascaded IPFC

<p class="JESAbstract">In recent years, there is an immensely huge demand to power due to industrialization and modernization, butcorrespondingly the amplification of generation and transmission has not been done due to constrained resources and environmental limitations. The huge growth in demand leads to various problems in power systems. Heavy growth in semiconductor technology made power electronics plays a key role in solving these problems. Flexible AC transmission system (FACTS) devices are used for fixing various problems in power system. They are used for enhancing the existing transmission capabilities and improving the system dynamic performance so that to make transmission system flexible and efficient in operation. Inter line power flow controller (IPFC) is a latest generation series connected FACTS device, having capability of controlling power flow among multi line in a transmission network. In this paper cascaded 5 level inverter is used as the inverter module for IPFC. Control techniques play a vital role in power flow control in the system, with the main objective of minimization of harmonics and obtaining a variable output with maximum fundamental component. This paper discusses various comparative case studies on IPFC with cascaded 5 level inverter using SPWM and SVM control techniques.</p>

Protection Placement for Power System State Estimation Measurement Data Integrity

In this article, a protection placement problem for power network measurement system data integrity is considered. The placement problem is motivated from [G. Dan and H. Sandberg, “Stealth attacks and protection schemes for state estimators in power systems,” in Proc. 1st IEEE Int. Conf. Smart Grid Commun ., 2010, pp. 214–219], where supervisory-control-and-data-acqui-sition and phasor measurement unit measurements can be selectively encrypted and protected to prevent false data injection attacks. The problem is shown to be NP-hard and an integer linear programming formulation is provided based on the topological observability condition by [G. Krumpholz, K. Clements, and P. Davis, “Power system observability: A practical algorithm using network topology,” IEEE Trans. Power App. Syst. , vol. PAS99, no. 4, pp. 1534–1542, Jul. 1980.]. The description of the observability condition requires a graph connectivity constraint, which is found to be most effectively described by the Miller–Tucker–Zemlin conditions. For a specialization without line power flow measurements, the protection placement problem can be modeled by a domination-type integer linear program that is much easier to solve than the general formulation requiring graph connectivity. Numerical studies with IEEE benchmark and other large power systems with more than 2000 buses indicate that by using the proposed formulations, the protection placement problem can be solved in a negligible amount of time in realistic application settings.

A Method for Harmonic Power Tracing by Using Upstream and Downstream Distribution Matrices

In this paper, an algorithm to find the harmonic power flow path for every generator and demand is proposed. In the proposed algorithm, the exact knowledge of harmonic power values is not required to determine the path. Our approach is based on Bialek’s tracing method, which specifies the contribution of each nodal generation/demand in power flow of a particular line. Our approach is faster than Bialek’s method in terms of computation due to the fact that upstream and downstream distribution matrices as well as nodal demand and generation matrices have a much simpler structure. Our method resolves electricity tracing for harmonic problems in both upstream and downstream aspects, resulting in two sets of answers: one for the harmonic power flow path of generator nodes and the other for that of demand nodes. To illustrate our algorithm, a step-by-step solution to a sample case study is provided here using the proposed algorithm. To verify our method, the results of our algorithm for a sample 5-bus power network and the IEEE 14-bus test system are compared to those of Bialek’s method. Finally, the proposed method is applied for harmonic frequency and used to find the path of harmonic power flow in a network.

Characterizing Tolerable Disturbances for Transient-State Safety in Power Networks

This paper develops methods to compute the set of disturbances on a power network that do not tip the frequency of each bus and the power flow in each transmission line beyond pre-defined bounds. For a linearized AC power network model, we consider scenarios with varying degree of knowledge about the form of the disturbance. We propose a sampling method to provide inner and outer approximations with tunable accuracy of the set of tolerable disturbances. The complexity of computing such set approximations is a function of the number of sampling points. We introduce an error metric to measure the gap between the approximations and design an algorithm that finds, for fixed number of sampling points, the sampling sequence that minimizes its value. Simulations on the IEEE 39-bus power network illustrate our results.

Load Frequency Control of HVDC Link Interconnected Power System Using Genetic Algorithm

Advances in power electronics have improved grid support functions such as tie-line power control and frequency control, making renewable generation and High Voltage DC (HVDC) links more common in power system applications. Load Frequency Control (LFC) systems handle the complex interactions between the distributed generator and the control area with the HVDC link. In this work, LFC of a two-zone system including parallel AC/DC transmission links has been analysed. The parameters of this system are optimised using advanced genetic algorithm resulting in improved performance of system in terms of reduction in peak overshoots and settling time of frequency measurement, tie line power flow and area control error signals in an interconnected power system. The advantage of having parallel HVDC links is also demonstrated when performance is compared to system interconnected with only AC tie line.

Resilient protection scheme preserving system integrity during stressed condition

During stressed system condition, power flow in transmission lines may substantiate and affect seen impedance of distance relay resulting in maloperation. Such a situation may initiate cascaded tripping leading to blackout. Proper coordinated blocking and tripping schemes of distance relays become essential to avoid such a relay malfunction and thus preserving system integrity. In this study, a resilient protection scheme is proposed employing adaptive zone-1 setting, thereby preventing relay maloperation during stressed system condition. The scheme uses a prefault data of both end distance relays to accomplish the proposed adaptive relay setting for the purpose. The performance of the proposed scheme is tested on the IEEE 118 bus system using PSCAD/EMTDC simulation data and is found to be accurate.

Optimal TCSC placement for congestion management in deregulated power systems using antlion optimization algorithm

Congestion management is one of the important issues in the deregulated power systems. There are several methods to eliminate congestion. Utilizing FACTS devices is an appropriate option for large-scale and quick control of flows of transmission lines. FACTS devices such as Thyristor Controlled Series Capacitor (TCSC) can help to mitigate the transmitting flow of power in the congested lines, which leads to an increase in the network loading ability as well as reduction of both losses and production costs. Due to the considerably high price of FACTS devices, it is important to determine their optimum location on the network. Accordingly, in this paper, the Antlion optimization algorithm (ALO) has been employed to conduct a congestion management analysis to determine the optimal location for the installation of TCSC, which is simulated on an IEEE 14-bus test system subject to satisfy the constraints of the market environment.

Performance comparison using firefly and PSO algorithms on congestion management of deregulated power market involving renewable energy sources

The power industry across the globe is subjected to a sweeping change in its business as well as in an operating model where the monopoly utilities are being liberalized and opened up for competition with private players. As an outcome of this, the transmission corridors evacuating the power of inexpensive generators would be burdened if all such transactions are admitted. One of the most proficient techniques for congestion management is rescheduling the generators. This research paper suggests a framework to regulate the power flows of the transmission lines within the stipulated limit in a deregulated electricity market environment through rescheduling with and without renewable energy sources (RES). The problem of rescheduling is framed with the intention of lessening the congestion cost. Unlike the traditional method, the best location for the placement of RES is established utilizing a novel weighted locational marginal price (LMP)-based method. The firefly algorithm (FA) and particle swarm optimization (PSO) algorithm are employed in order to get optimized results. The realistic cases are considered, and the results obtained with and without RES using FA and PSO are compared to prove the research study. The efficacy of the method is explored with IEEE 30-bus system.