scholarly journals Fast Heuristic AC Power Flow Analysis with Data-Driven Enhanced Linearized Model

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3308
Author(s):  
Xingpeng Li
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Flow Model ◽  
Reactive Power ◽  
Unit Commitment ◽  
Flow Analysis ◽  
Data Driven ◽  
Dc Power ◽  
Ac Power

Though the full AC power flow model can accurately represent the physical power system, the use of this model is limited in practice due to the computational complexity associated with its non-linear and non-convexity characteristics. For instance, the AC power flow model is not incorporated in the unit commitment model for practical power systems. Instead, an alternative linearized DC power flow model is widely used in today’s power system operational and planning tools. However, DC power flow model will be useless when reactive power and voltage magnitude are of concern. Therefore, a linearized AC (LAC) power flow model is needed to address this issue. This paper first introduces a traditional LAC model and then proposes an enhanced data-driven linearized AC (DLAC) model using the regression analysis technique. Numerical simulations conducted on the Tennessee Valley Authority (TVA) system demonstrate the performance and effectiveness of the proposed DLAC model.

scholarly journals Load Flow Analysis in Hybrid AC-DC Transmission Network

2021 ◽  
pp. 617-624
Author(s):  
Ajith M ◽  
Dr. R. Rajeswari
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Power Flow ◽  
Reactive Power ◽  
Short Circuit ◽  
Flow Analysis ◽  
Load Flow ◽  
System Stability ◽  
And Control

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.

scholarly journals Study on the Key Problems of UHVAC/DC Power Grids with New Generation Large Synchronous Condenser

2018 ◽  
Vol 57 ◽  
pp. 03003
Author(s):  
Xiao Fan ◽  
Zhou Kunpeng ◽  
Wang Tao ◽  
Cao Kan ◽  
Rao Yuze
Keyword(s):  
Renewable Energy ◽  
Power System ◽  
Reactive Power ◽  
Power Transmission ◽  
Excitation Control ◽  
Synchronous Condenser ◽  
Dc Power ◽  
Ac Power ◽  
New Generation ◽  
Dc Power Transmission

In order to cope with the great pressure caused by the gradually exhaustion of fossil energy and environmental protection and climate warming, the development and application of the renewable energy has become an important foundation and development direction in the field of energy. However, due to the impact of energy and resource endowment, China’s load center and renewable energy base into the characteristics of long-range reverse distribution, the use of long-distance large-capacity transmission potential is necessary. With the “strong DC system and weak AC system” problem of the company power grid is increasingly prominent, the higher demand of dynamic reactive power support is put forward in the UHV DC power transmission project. Then, the large-capacity dynamic reactive power of new generation synchronous condenser is large-scale built up in the UHV DC/AC power system. Due to the high requirement of response speed and capacity in the UHV DC power transmission, the structure, dynamic characteristics, excitation control and relay protection and other aspects of the large synchronous condenser are different from generators and traditional synchronous condenser. Based on this, the dynamic reactive power demand of UHV DC power system is analyzed in this paper. Then, the main situation of large synchronous condenser is considered. In addition, the key points of the excitation control system and protection system are also discussed in this paper. There are important theoretical and practical significance for the safe and reliable operation of the UHV DC/AC power system.

scholarly journals Demodulation of Three-Phase AC Power Transients in the Presence of Harmonic Distortion

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2341
Author(s):  
Benjamin T. Gwynn ◽  
Raymond de Callafon
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Reactive Power ◽  
Harmonic Distortion ◽  
Transient Effects ◽  
Active And Reactive Power ◽  
Reactive Power Flow ◽  
Ac Power ◽  
Rlc Circuit ◽  
Smart Inverters

Load switches in power systems may cause oscillations in active and reactive power flow. Such oscillations can be damped by synthetic inertia provided by smart inverters providing power from DC sources such as photovoltaic or battery storage. However, AC current provided by inverters is inherently non-sinusoidal, making measurements of active and reactive power subject to harmonic distortion. As a result, transient effects due to load switching can be obscured by harmonic distortion. An RLC circuit serves as a reference load. The oscillation caused by switching in the load presents as a dual-sideband suppressed-carrier signal. The carrier frequency is available via voltage data but the phase is not. Given a group of candidate signals formed from phase voltages, an algorithm based on Costas Loop that can quickly quantify the phase difference between each candidate and carrier (thus identifying the best signal for demodulation) is presented. Algorithm functionality is demonstrated in the presence of inverter-induced distortion.

scholarly journals Corrective Control by Line Switching for Relieving Voltage Violations Based on A Three-Stage Methodology

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1206 ◽  
Author(s):  
Zhengwei Shen ◽  
Yong Tang ◽  
Jun Yi ◽  
Changsheng Chen ◽  
Bing Zhao ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Detailed Analysis ◽  
High Speed ◽  
Power Flow ◽  
Large Scale ◽  
Online Application ◽  
Multiple Line ◽  
Ac Power ◽  
Line Switching

An online line switching methodology to relieve voltage violations is proposed. This novel online methodology is based on a three-stage strategy, including screening, ranking, and detailed analysis and assessment stages for high speed (online application) and accuracy. The proposed online methodology performs the tasks of rapidly identifying effective candidate lines, ranking the effective candidates, performing detailed analysis of the top ranked candidates, and supplying a set of solutions for the power system. The post-switching power systems, after executing the proposed line switching action, meet the operational and engineering constraints. The results provided by the exact Alternating Current (AC) power flow are used as a benchmark to compare the speed and accuracy of the proposed three-stage methodology. One feature of the methodology is that it can provide a set of high-quality switching solutions from which operators may choose a preferred solution. The effectiveness of the proposed online line switching methodology in providing single-line switching and multiple-line switching solutions to relieve voltage violations is evaluated on the IEEE 39-bus and 2746-bus power system. The CPU time of the proposed methodology compared with that under AC power flow constitutes a speed-up of 9905.32% on a 2746-bus power system, showing good potential for online application in a large-scale power system.

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

2021 ◽  
Vol 7 (03) ◽  
pp. 280-285
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Voltage Stability ◽  
Reactive Power ◽  
Fitness Function ◽  
Electrical Power ◽  
Stability Index ◽  
Unified Power Flow Controller ◽  
Facts Devices

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

scholarly journals LP based solution for Security Constrained Optimal Power Flow including Power Routers

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Power System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Electrical Power ◽  
Flow Analysis ◽  
Time Frame ◽  
Electrical Power System ◽  
Piecewise Linearization ◽  
Dc Power ◽  
Optimal Power

Power Routers offers many benefits to the power system, it helps in improving the existing transmission asset utilization. Security Constrained Optimal Power Flow (SCOPF) is becoming more important in the electrical power system especially in the present deregulated environment. This paper focuses on completely linearizing the complex non-linear SCOPF problem. The objective function is linearized using Piecewise linearization technique and the constraints are framed using linear sensitivity factors. A formal extension is made to the traditional SCOPF by including power router control in the post contingency time frame. DC power flow analysis is used to calculate the real power flow in the lines.Thus, in this paper, further minimization of cost is achieved by using Power Router control and it is compared with the conventional SCOPF.

Optimal Location of TCSC, TCPS, and SVC Devices for Solving OPF and ORPD Problem Using Different Evolutionary Optimization Techniques

2018 ◽  
pp. 244-273
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Phase Shifter ◽  
Reactive Power ◽  
Test System ◽  
Optimal Location ◽  
Thyristor Control ◽  
Evolutionary Optimization Techniques

The secure operation of power system has become a topmost issue in today's largely complicated interconnected power systems. This chapter presents the implementation of grey wolf optimization (GWO), teaching-learning-based optimization (TLBO), biogeography-based optimization (BBO), krill herd algorithm (KHA), chemical reaction optimization (CRO), and hybrid CRO (HCRO) approaches to find the optimal location of various FACTS devices such as thyristor control series compensator (TCSC), thyristor control phase shifter (TCPS), and static VAR compensator (SVC) to solve optimal power flow (OPF) and optimal reactive power dispatch (ORPD) in power system. In this chapter, a standard IEEE 30-bus test system with multiple TCSC and TCPS and SVC devices are used for different single and multi-objective functions to validate the performance of the proposed methods. The simulation results validate the ability of the HCRO to produce better optimal solutions compared to GWO, TLBO, BBO, KHA, and CRO algorithms.

Integrated Power Flow Analysis with Large-scale Solar Photovoltaic Power Systems Employing N-R Method

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Girisha H Navada ◽  
K. N. Shubhanga
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Flow ◽  
Large Scale ◽  
Control Strategies ◽  
Linear Equations ◽  
Flow Analysis ◽  
Load Flow ◽  
Flow Equations ◽  
Single Machine Infinite Bus

Abstract A method is proposed to modify the conventional load flow programme to accommodate large-scale Solar PhotoVoltaics (SPV) power plant with series power specifications. The programme facilitates easy handling of any number of SPV systems with standard control strategies such as pf-control and voltage-control, considering solar inverter’s power constraints. In this method, the non-linear equations related to SPV systems, located at multiple locations, are solved with the main load flow equations in an integrated fashion, considerably reducing the implementation task. This task is achieved by augmenting the inverter buses to the existing power system network in such a way that the changes required in the conventional programme are minimal. To show the effectiveness of the proposed method, it is compared with the alternate-iteration method popularly followed in the literature. The workability of the proposed method has been demonstrated by using a Single Machine Infinite Bus (SMIB) system and the IEEE14-bus power system with SPV systems. Various test cases pertaining to meteorological variables and control strategies are also presented.

Shunt-Series FACTS Devices on Network Constrained Unit Commitment

2016 ◽  
Vol 5 (1) ◽  
pp. 40
Author(s):  
G.A. M. Hosaini Hajivar ◽  
S.S. Mortazavi
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Reactive Power ◽  
Unit Commitment ◽  
Normal Operation ◽  
Voltage Profile ◽  
Facts Devices ◽  
Reactive Power Flow ◽  
Generation Cost ◽  
Shunt Series

<p>Shunt-Series FACTS Devices (SSFD) would play an important role in maintaining security and reduce Total Generation Cost (TGC) in the economical operation of power systems. The application of this devices to the AC model of Network-Constrained Unit Commitment (NCUC) for the day ahead scheduling is presented in this paper. The proposed AC model of NCUC with SSFD would include active and reactive power flow constraints which increase the network controllability at normal operation. A general SSFD model is introduced for the reactive power management in NCUC which is based on the reactive power injection model (RPIM). The case studies reveal that power transfer capability and voltage profile of the power system is improved by compensating SSFD. Meanwhile simulation results demonstrate the combined use of these devices to NCUC have a significant impact on maintaining network security,  lower TGC and increase using the maximum capacity of the existing transmission network.</p><p> </p>

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