scholarly journals Development of a Static Equivalent Model for Korean Power Systems Using Power Transfer Distribution Factor-Based k-Means++ Algorithm

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6663
Author(s):  
Bae-Geun Lee ◽  
Joonwoo Lee ◽  
Soobae Kim

This paper presents a static network equivalent model for Korean power systems. The proposed equivalent model preserves the overall transmission network characteristics focusing on power flows among areas in Korean power systems. For developing the model, a power transfer distribution factor (PTDF)-based k-means++ algorithm was used to cluster the bus groups in which similar PTDF characteristics were identified. For the reduction process, the bus groups were replaced by a single bus with a generator or load, and an equivalent transmission line was determined to maintain power flows in the original system model. Appropriate voltage levels were selected, and compensation for real power line losses was made for the correct representation. A Korean power system with more than 1600 buses was reduced to a 38-bus system with 13 generators, 25 loads, and 74 transmission lines. The effectiveness of the developed equivalent model was evaluated by performing power flow simulations and comparisons of various characteristics of the original and reduced systems. The simulation comparisons show that the developed equivalent model maintains inter-area power flows as close as possible to the original Korean power systems.

Author(s):  
Prakash Kerur ◽  
R. L. Chakrasali

The major challenges in deregulated system are determination of available transfer capability on the interconnected transmission lines. Electricity industry deregulation is the required for creating a competitive market throughout the world, which instigate new technical issues to market participants and Power System Operators (PSO). Power transfer capability is a crucial parameter to decide the power flow in the lines for further transactions and the estimation of Transfer Capability decides the power transactions based on the safety and ability of the system. This parameter will decide if an interconnected network could be reliable for the transfer of bulk power between two different areas of the network without causing risk to system consistency. The Power Transfer Distribution Factor (PTDF) is the sensitivity index, which decides the transfer capability in the interconnected network under deregulated power systems. This experiment is conducted on IEEE-6 bus system using Power World Simulator to determine the transfer capability in deregulated system under line outage condition.


Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2052
Author(s):  
Milena Kurzawa ◽  
Cezary Jędryczka ◽  
Rafał M. Wojciechowski

In this paper, the feasibility of applying a multi-branch equivalent model employing first- and second-order Cauer circuits for the analysis of electromagnetic transducers used in systems of wireless power transfer is discussed. A method of formulating an equivalent model (EqM) is presented, and an example is shown for a wireless power transfer system (WPTS) consisting of an air transformer with field concentrators. A method is proposed to synthesize the EqM of the considered transducer based on the time-harmonic field model, an optimization algorithm employing the evolution strategy (ES) and the equivalent Cauer circuits. A comparative analysis of the performance of the considered WPTS under high-frequency voltage supply calculated using the proposed EqM and a 3D field model in the time domain using the finite element method (FEM) was carried out. The selected results of the conducted analysis are presented and discussed.


2019 ◽  
Vol 9 (18) ◽  
pp. 3769
Author(s):  
Yi-Hung Liao ◽  
Yue Lin

This paper presents a bidirectional wireless power transfer system for mobile power applications. A novel 2-switch bidirectional wireless power transfer system with dual-side control is proposed for mobile power applications. Although only two switches are adopted, the energy can be transferred from the transmitter side to the receiver side and vice versa. The term bidirectional means that the power-flow is bidirectional and also that the transmitter is also a receiver and the receiver is also a transmitter. The output energy can be easily controlled by the duty ratios of the two switches. Thus, the proposed bidirectional power transfer system uses only one circuit to achieve bidirectional power transfer. Hence, the system cost and volume can be reduced so that the system is small and convenient for mobile power systems, portable and/or wearable electronic devices. A prototype system is constructed and the experimental results verify the validity of the proposed bidirectional wireless power transfer system.


2014 ◽  
Vol 1070-1072 ◽  
pp. 200-203
Author(s):  
Ze Tian Wei ◽  
Wen Ying Liu ◽  
Fu Chao Liu ◽  
Jian Zong Zhuo

This paper firstly analyzes the mechanism of transmission line and transformer loss and illustrates the equivalent model and calculating method. Then creates a simple three-node model and discusses the main factors which affect the grid loss with adequate formula. At last, we draw a concise conclusion that there are several factors affecting grid loss. The main factors are the location of wind power access, the active power flow of transmission lines, the active power output of wind farms and the voltage level of wind power access.


2019 ◽  
Vol 40 ◽  
pp. 69
Author(s):  
Bruno Pereira do Nascimento ◽  
Caison Rodrigues Ramos ◽  
Aline Brum Loreto

The basic function of the Electric Power System is to supply electrical energy with quality and when requested. For this to be possible some analysis of the system is required, among them Power Flow Analysis. This analysis is important for the delineation of the power systems, as well as in the definition of the best conditions of operation, control and supervision of the existing systems. The system is modeled as follows: Generators, Loads, Reactors and Capacitors are connected between any node and the ground node, since the transmission lines and transformers are connected between any two nodes. Thus, the admittance matrix of the system will be generated through nodal analysis that will be solved by numerical methods. One of the objectives of this work aims to perform the power flow analysis of a system with the aid of numerical methods. Another objective is as well as to verify the accuracy of the results, with solutions obtained by the methods of Gauss Elimination, LU Factoration, Gauss Seidel and Crout Method, implemented in C language. The analysis of the accuracy of the results occurred through the relative error in comparison to the results obtained by MatLab software.


2020 ◽  
Vol 9 (5) ◽  
pp. 1755-1765
Author(s):  
Mohammed Y. Suliman ◽  
Mahmood T. Al-Khayyat

The power flow controlled in the electric power network is one of the main factors that affected the modern power systems development. The unified power flow controller (UPFC) is a FACTS powerful device that can control both active and reactive power flow of parallel transmission lines branches. In this paper, modelling and simulation of active and reactive power flow control in parallel transmission lines using UPFC with adaptive neuro-fuzzy logic is proposed. The mathematical model of UPFC in power flow is also proposed. The results show the ability of UPFC to control the flow of powers components "active and reactive power" in the controlled line and thus the overall power regulated between lines.


Author(s):  
Ajith M ◽  
Dr. R. Rajeswari

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.


Author(s):  
D Narasimha Rao ◽  
T Surnedra ◽  
S Tara Kalyani

<p>Modern power systems demand the need of active power flow with the help of Power Electronics control devices is needed. In the family of Flexible AC Transmission devices (FACTS), Dynamic PFC (DPFC) offers the same controlling function as Unified PFC (UPFC), comprising the control of transmission angle, bus voltage and line impedance. A technical modification of UPFC is DPFC in which fluctuations of voltage at DC link is eliminated that enables the individual operation as series and parallel controllers. The concept of DFACTS is used in design of the series converter. The replacement of  the  high  rating  three  phase  series  converter with  the multiple low rating single phase converters results in cost reduction and increases reliability greatly. This DC Link is used to transfer the real power between two converters in UPFC such as in DPFC which eliminates the 3rd harmonic frequencies at transmission lines. D-FACTS converters are acting as insulation between high voltage phases acts as 1-ᴓ floating with respect to ground. These results in lower cost for the DPFC system compared to the UPFC. This paper describes the comparison of PI and Sliding Mode Controllers which conclude that SMC is a better control strategy compared to PI.</p>


2019 ◽  
Vol 10 (1) ◽  
pp. 242 ◽  
Author(s):  
Ali Raza ◽  
Armughan Shakeel ◽  
Ali Altalbe ◽  
Madini O. Alassafi ◽  
Abdul Rehman Yasin

In this paper, improvement in the power transfer capacity of transmission lines (TLs) by utilizing a multi-terminal high voltage direct current (MT-HVDC) grid is discussed. A multi-terminal HVDC grid designed for wind power can be used as an extra transmission path in interconnected systems during low wind conditions, and provides extra dynamic stability and security. This paper deals with the power transfer capacity as well as the small signal (SS) stability assessments in less damped oscillations accompanying inter area modes. Computation of the maximum allowable power transfer capability is assessed via DC optimal power flow-based control architecture, permitting more power transfer with a definite security margin. The test system is assessed with and without the exploitation of MT-HVDC grid. Simulation work is done using a generic computational framework i.e., international council on large electric systems (CIGRE) B4 test bench with a Kundur’s two area system, shows that voltage source converters (VSCs) provide excellent control and flexibility, improving the power transfer capability keeping the system stable.


2014 ◽  
Vol 573 ◽  
pp. 747-756 ◽  
Author(s):  
B. Karthik ◽  
Jerald Praveen Arokkia ◽  
S. Sreejith ◽  
S. Rangarajan Shriram

Application of Flexible AC Transmission Systems (FACTS) devices in a power system is a promising and more efficient way for the transfer and control of bulk amount of power. One of the problems encountered in power-systems operation is the generation of unbalanced voltages and currents in the presence of long transmission lines with few or no transpositions. This includes possible unbalances arising in source and load conditions, or indeed any items of plant such as shunt and series reactors. To improve or investigate these unbalance effects in any detail, a 3-phase load-flow solution that allows representation of all possible unbalances as they exist in the power-systems network without making any assumptions is essential. This paper deals with the three phase power flow incorporating Static Var Compensator (SVC). Here SVC is modeled using variable reactance modeling technique and incorporated into the single phase and three phase load flow. Newton Raphson power flow algorithm is adopted here. The performance of SVC to control the power flow and regulating voltage in the network is discussed. The performance analysis is carried out for 4 case studies namely single phase power flow, single phase power flow with SVC, three phase power flow and three phase power flow with SVC. The change in power flow and losses due to the unbalanced load condition in the three phases in illustrated. The studies are carried out in a standard 5 bus test system. Keywords: Three Phase Power flow, Static Var Compensator, Unbalanced system, Negative sequence components, Zero sequence components.


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