C.M. Yam · DR-NTU (Nanyang Technological University) · 2008
In the past, power systems were relatively simple and self-sufficient; power exportation and importation were rare and few. At that time it was generally understood that power systems could not be controlled fast enough to handle the system dynamic conditions. Traditionally systems were designed with fixed or mechanically switched series and/or shunt reactive compensations, together with voltage-regulating and phase-shifting transformer, to optimize line impedance, voltage variation, and power flow control under steady state or \nslowly changing load conditions. In recent years, energy, environment, right-of-way, and capital cost issues have delayed the construction of both generation facilities and new \ntransmission lines, while the demand f o relectric power has continued to grow. These issues have challenged power system engineers today to use the existing transmission facilities to greater effect and efficiency.
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Jiabao Wu, Wenyi Li · 2023
Compared to the AC power flow model, the DC power flow calculation model is straightforward. The absolute error and relative error are computed using the DC power flow computation's simplified parameters, and the active power cost is quantified. The relationship between the error and the reactance ratio of the network components and the network loss of the system is analyzed. Combined with the IEEE test system of different scales, the causes of the active power errors of the AC power flow and the DC power flow are analyzed. Results: The active power error of the DC method is caused by ignoring the branch resistance of the operating system, and the net loss of the system is positively correlated with the active power error. The experimental findings can serve as a guide and a point of reference for the interaction between power flow, network architecture, and operational conditions.
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Vakula Peesari · CSUN ScholarWorks (California State University, Northridge) · 2010
Project (M.S., Electrical and Electronic Engineering)--California State University, Sacramento, 2010.
Cited by 0Open access
Roslan, Muhamad Fazril · UTPedia (Universiti Teknologi Petronas) · 2016
Power flow is an important tool used for planning, to determine the best operation for a power system and exchange of power between utility companies. The power flow study in a UTP Microgrid (a group of interconnected loads and distributed energy resources within the grid) constitutes a study of paramount importance. The study reveals the electrical performance and power flows (real and reactive) for specified condition when the system is operating under steady state. This research is conducted to make a simulated model to study on how power flow in UTP microgrid network. From the findings obtained, it may give an alternative to monitor power flow using Power World Simulator Software.
Cited by 0
Ashwin Kumar Sahoo, Subhransu Sekhar Dash, T. Thyagaraja · Journal of Applied Sciences · 2010
Cited by 17
Luis Sainz, J. Pedra · IEEE Transactions on Power Delivery · 1995
Multiple harmonic load flow study solutions are mathematically possible but not physically real. The Newton method can provide these false solutions when an ill-conditioned power system is studied. This problem is more usual in the presence of harmonics. This paper analytically studies a kind of raise solution in networks with AC/DC power converters. These false solutions are easily detected because they present a negative firing angle of the power converter. A simple example is studied where the Newton method gives a false solution.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
Cited by 1
Naga bhushan, Manjunath G Kadashetti · International Journal of Engineering Trends and Technology · 2015
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Anumaka, M. C.; Department of Electrical / Electronic Engineering,Faculty of Engineering,Imo State University,Owerri, Nigeria · IJITR International Journal of Innovative Technology and Research - IJITR International Journal of Innovative Technology and Research · 2014
Major challenges confronting the power system engineers and operators include the ease to determine the real and reactive power losses, power flows,and ability to plan ahead.This paper accentuates the use of power flow study to solve the above articulated problems in the electric power systems.It examines the causes and effects of embarking upon power flow study on ac power system, and suggests possible techniques and methods of executing power flow study.
Cited by 0Open access
Murtadha Sami Albo Kareem, Ștefan Gheorghe · 2019
The power flow solution is one of the more significant issues in power systems. In this article we will describe a comparison between using of two tools for Power flow and Voltage analysis: program 1 and program 2. Our study case includes the results in the calculation of Power Flow and Voltage analysis in the nodes of High Voltage network. The power network has 13 nodes, 11 generators (Five generating units), 27 power transformers, from which 16 transformers are used as a loads, and the network operating at 10.5 kV up to 220 kV. The loads are depending on the voltage. The total losses in this network are calculated, and the level of voltages in all of nodes, calculated with both programs. Also, we do operate the power network in the best case in terms of Reduce losses in the network, taking into account the voltages regulation. The study is focused on the voltage control in the power network. Solutions for dynamic control of the voltage in power system are proposed in the paper.
Cited by 5
Xin Rui Zhang, Zhi Li · Applied Mechanics and Materials · 2014
The power flow calculation is a basic electrical calculation which is to study the steady state operation of power system. Its task is to decide the whole system running state according to the given operating conditions and the network structure. The power flow calculation is the basis of the stability calculation and fault analysis of power system. In this paper, through a four machine 11 node example, we shows that the influence of generator node type on power flow calculation.
Cited by 0
Zijue Xie, Qian Yu · 2019
DPFC is composed of several series converters, which can be installed and disassembled in stages and batches. This paper considers the ability of DPFC to regulate the power grid, and proposes the investment cost function which takes the regulation variables of the distributed converter into account. Due to increased transmission capacity, the economic benefit function and the economic revenue function are caused by the expansion of voltage safety and stability range, and the economic revenue function is caused by expanding the stability range of power angle. Meanwhile, an objective function Z, which takes into account the security constraints of power grid operation, is proposed to maximize the difference between revenue and expense. Finally, by solving the constrained equation based on the dynamic programming method, the capacity of DPFC built in batches with the largest revenue could be derived, and the capital idleness and equipment depreciation losses caused by one-off construction will be avoided. Implementation results show that the proposed method is effective.
Cited by 2
Takuji Chida, Yoshihiko Sato, Jun Sugawara et al. · IEEJ Transactions on Power and Energy · 1997
The increasing complexity of AC power networks requires a high performance power flow control system in order to obtain a desired power flow and enhance static and dynamic stability. One of the most effective power electronic systems to satisfy these requirements is a UPFC (Unified Power Flow Controller) employing self-commutated converters. This paper presents basic control strategies and simulation results for the UPFC using EMTP (Electro-Magnetic Transients Program). The simulations were carried out for start and stop operations, power flow change operations in normal system conditions, as well as operations during system fault conditions. Thyristor based bypass switches are used for the protection of the series compensator of the UPFC from system fault currents, and satisfactory protection capability was confirmed.
Cited by 3Open access
Fuel and Energy Abstracts · 1995
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Mohit Lakha, Navneet Singh Bhanu, Prof. Kuldeep Singh Kooner et al. · International Journal of Research Publication and Reviews · 2023
A flexible AC transmission system (FACTS) device called Unified Power Flow Controller (UPFC) can adjust the voltage, phase angle and impedance of a transmission line to regulate the flow of real and reactive power.This paper shows how to design and simulate UPFC using amplifiers and rectifiers in MATLAB/SIMULINK.It also evaluates the impact of UPFC on the power quality and stability of a transmission line using data from GNDEC, Ludhiana.The results indicate that UPFC can improve the power flow capacity and ensure power continuity in the power system.The paper also contrasts the results with a reference system without UPFC to prove its effectiveness.
Cited by 1Open access
Alebachew Kassie Anley, Yesuneh Getachew Taye, Estifanos Abeje Sharew et al. · EAI/Springer Innovations in Communication and Computing · 2026
Cited by 0
Shuyan Liu, Jiazhu Xu, Danhu Li et al. · 2024
As the pace of decarbonization accelerates within the power sector, clarifying carbon emission responsibility is becoming increasingly necessary. Deep peak shaving, as an important ancillary service, contributing significantly to the efficient and environmentally-friendly management of power systems. In view of the deep peak shaving characteristics of pure condensing thermal units, the deep peak shaving model is established. And based on carbon emission flow, the optimal power flow model of power system considering deep peak shaving is established. The effect of the proposed model on carbon emission responsibility allocation, the influence of introducing deep peak shaving and wind power penetration rate on carbon emissions were analyzed in detail through a case simulation. The research shows that carbon emission responsibility of the power system introducing deep peak shaving can be effectively allocated by the proposed model. The reasonable introduction of deep peak shaving when there is much abandoned wind, along with higher wind penetration when sufficient absorption capacity exists, both help reduce system carbon emissions and the carbon intensity of nodes with high wind power inflow proportion.
Cited by 0
Yow-Think Lin · Rice Digital Scholarship Archive (Rice University) · 1980
Using the finite difference technique, the steady flow of a viscoelastic fluid through a contraction/expansion and a modified Graetz heat transfer problem for power-law fluids between parallel plates are numerically studied.\nThe constitutive model used for the viscoelastic fluid flow extends the Maxwell equation of linear viscoelasticity to the non-linear region by letting both relaxation time and elastic modulus depend upon the existing structure. Based on the calculations for a 3:1/1:3 contraction/expansion geometry with fully developed simple shearing flows at the entrance and exit, there exists a transition range for this fluid model, in terms of the Weissenberg number, beyond which elastic effects appear to become less dominant. The upstream vortex detachment length before the contraction is shown to grow with increasing Weissenberg number, and then reach a maximum value, until no converged solution can be obtained or possibly unsteady flow starts to develop.\nHeat transfer to polymer melts or solutions flowing in a parallel plate system is of great importance in polymer processing, as for example in extrusion through a large aspect ratio slit die. The present work was undertaken to solve the energy equation for power-law fluids under various circumstances, including a temperature-dependent viscosity, viscous dissipation and heat convection across streamlines induced by the abrupt change of boundary temperature and subsequent velocity field rearrangement. In addition to the numerical solutions given, an analytical approximation method for the Graetz-Nusselt problem is also presented for comparison. This method divides the domain into two sections for which two corresponding solutions, approximated by polynomials, are solved by a thermal boundary layer theory and an integral method respectively. These two approximate solutions are then matched at the intersection to give a continuous and consistent temperature profile. Although the analytical solutions application is limited to the case with a temperature-independent viscosity, this simple analysis is believed to be better than the previous methods available in the literature.
Cited by 0Open access
Yanqing Zhao · 2012
This paper introduces the general circuit model based on interphase power controller,analyzes the characteristics of IPC from the aspect of tie-line power flow control and the working characteristics of thyristor-controlled series capacitor(TCSC),and proposes the structure of thyristor controlled interphase power controller(TCIPC),a controller which can control the tie-line power flexibly,fast and constantly and acquire relatively wide range for parameters adjustment by relatively small capacitor.The Simulation result of TCIPC power flow control proves the feasibility in tie-line power flow control.
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寺尾 信一郎, Shin-ichiro Terao, 定本 知徳 et al. · Tokyo Tech Research Repository (Tokyo Institute of Technology) · 2020
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Roy Shawanti, Sarker Jayanti, Paramanik Sayan et al. · i-manager s Journal on Circuits and Systems · 2024
This paper presents a conceptual study of the Unified Power Quality Conditioner (UPQC) in mitigating voltage swell and sag occurrences on power distribution networks. A distinctive feature of UPQC is its capability to inject voltage within a range of 0° to 360° relative to the utility or Point of Common Coupling (PCC) voltage phase angle. Leveraging this capability, UPQC can either inject or absorb active power, enabling operation in modes of zero active power consumption, active power absorption, or active power delivery. Specifically, during voltage swell and sag conditions, the series Active Power Filter (APF) component of UPQC operates in active power delivery and absorption modes, respectively. Simultaneously, the shunt APF component aids the series APF by stabilizing the DC link voltage at a constant level. The shunt APF also compensates for the load's reactive power demands and reduces harmonics generated by it. MATLAB/Simulink simulation results validate the analysis for different types of loads, such as linear, non-linear, sensitive, and EV charging stations.
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