scholarly journals Power flow incorporating cost-based droop control strategies for ac autonomous microgrids

2020 ◽  
pp. 28-32
Author(s):  
Pham Nang Van Pham
Keyword(s):  
Power Flow ◽  
Control Strategies ◽  
Flow Analysis ◽  
Load Flow ◽  
Cost Curve ◽  
Droop Control ◽  
Test Results ◽  
Autonomous Operation ◽  
Complex Power ◽  
Flow Study

Several methods of power flow analysis for autonomous microgrids have been suggested; however, the implementation of these methods is challenging because of the lack of a swing bus and droop control characteristics. This paper puts forward an innovative technique for the load flow study of microgrids that autonomously operate according to droop control strategies incorporating cost rather than traditional droop schemes. This approach aims to extend the application of conventional power flow methodologies. In this approach, the incremental cost that is derivative of the fuel cost curve with respect to power output is embedded in droop schemes. The proposed approach deploys the iterative procedure to impose complex power that injects through the swing node to zero, which represents the autonomous operation of microgrids. Test results validate that this approach is exact and straightforward to implement; therefore, it can be highly beneficial for operating and planning microgrids

scholarly journals Power Flow Analysis of Weakly Meshed Distribution Network Including DG

2018 ◽  
Vol 8 (5) ◽  
pp. 3398-3404 ◽  
Author(s):  
A. Al-Sakkaf ◽  
M. AlMuhaini
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Power Flow ◽  
Distribution Systems ◽  
Flow Analysis ◽  
Load Flow ◽  
Power Distribution Systems ◽  
Power Flow Analysis ◽  
Bus Voltage ◽  
Flow Study

Power flow is one of the essential studies in power system operation and planning. All steady-state parameters for power distribution systems, such as bus voltage magnitudes, angles, power flows, and power losses, can be calculated by conducting power flow analysis. Distribution system features differ from those of transmission system, rendering conventional load flow algorithms inapplicable. In this paper, three distribution power flow techniques are presented and tested to evaluate their performance when applied to a networked distribution system including distributed generation (DG). These are the distribution load flow (DLF) matrix, the enhanced Newton Raphson (ENR), and the robust decoupled (RD) method. IEEE 33-bus system is adopted for implementing the above methods. Radial and weakly meshed configurations are applied to the tested system with DG inclusion to investigate their influence on the power flow study findings.

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.

scholarly journals Power Flow Analysis of MMC-HVDC System with Margin Voltage and Voltage Droop Control Strategies

2020 ◽  
Author(s):  
Maxwel Da Silva Santos ◽  
Luciano Sales Barros ◽  
Rafael Lucas da Silva França ◽  
Flavio Bezerra Costa ◽  
Kai Strunz
Keyword(s):  
Power Flow ◽  
Control Strategies ◽  
Flow Analysis ◽  
Open Circuit ◽  
Droop Control ◽  
Power Flow Control ◽  
Hvdc System ◽  
High Voltage Direct Current ◽  
Modular Converter ◽  
The One

High voltage direct current (HVDC) systems are an alternative for transmission of energy with higher efficiency and lower electrical losses over long distances. HVDC systems have become more common with the evolution of power electronics, promoting the interest of research in power flow control techniques. The main objective of this paper is to perform evaluations of the power flow in a meshed multiterminal HVDC (MT-HVDC) system based on the multilevel modular converter (MMC). Two different control strategies were considered; The margin voltage; and the voltage droop strategies. Two assessment scenarios were considered: when an active power reference takes place in the system; and when a DC transmission line is open-circuit due to a failure in the DC grid. For both of these test cases, the system with the margin voltage control obtained a new balance of power flow with less oscillations in power andvoltage than the one with the voltage droop control.

scholarly journals Impedance Matching-Based Power Flow Analysis for UPQC in Three-Phase Four-Wire Systems

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2702
Author(s):  
Xiaojun Zhao ◽  
Xiuhui Chai ◽  
Xiaoqiang Guo ◽  
Ahmad Waseem ◽  
Xiaohuan Wang ◽  
...  
Keyword(s):  
Power Flow ◽  
Control Strategies ◽  
Impedance Matching ◽  
Flow Analysis ◽  
Point Of View ◽  
Impedance Model ◽  
Power Flow Analysis ◽  
Three Phase ◽  
System Node ◽  
Power Quality Conditioner

Different from the extant power flow analysis methods, this paper discusses the power flows for the unified power quality conditioner (UPQC) in three-phase four-wire systems from the point of view of impedance matching. To this end, combined with the designed control strategies, the establishing method of the UPQC impedance model is presented, and on this basis, the UPQC system can be equivalent to an adjustable impedance model. After that, a concept of impedance matching is introduced into this impedance model to study the operation principle for the UPQC system, i.e., how the system changes its operation states and power flow under the grid voltage variations through discussing the matching relationships among node impedances. In this way, the nodes of the series and parallel converter are matched into two sets of impedances in opposite directions, which mean that one converter operates in rectifier state to draw the energy and the other one operates in inverter state to transmit the energy. Consequently, no matter what grid voltages change, the system node impedances are dynamically matched to ensure that output equivalent impedances are always equal to load impedances, so as to realize impedance and power balances of the UPQC system. Finally, the correctness of the impedance matching-based power flow analysis is validated by the experimental results.

scholarly journals Distributing Load Flow Computations Across System Operators Boundaries Using the Newton–Krylov–Schwarz Algorithm Implemented in PETSc

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2910
Author(s):  
Stefano Rinaldo  ◽  
Andrea Ceresoli  ◽  
Domenico Lahaye  ◽  
Marco Merlo  ◽  
Miloš  Cvetković ◽  
...  
Keyword(s):  
Power Flow ◽  
Flow Analysis ◽  
Flow Simulation ◽  
Load Flow ◽  
Inexact Newton Method ◽  
Test Case ◽  
Flow Solver ◽  
Cross Border ◽  
System Operator ◽  
Schwarz Algorithm

The upward trends in renewable energy penetration, cross-border flow volatility and electricity actors’ proliferation pose new challenges in the power system management. Electricity and market operators need to increase collaboration, also in terms of more frequent and detailed system analyses, so as to ensure adequate levels of quality and security of supply. This work proposes a novel distributed load flow solver enabling for better cross border flow analysis and fulfilling possible data ownership and confidentiality arrangements in place among the actors. The model exploits an Inexact Newton Method, the Newton–Krylov–Schwarz method, available in the portable, extensible toolkit for scientific computation (PETSc) libraries. A case-study illustrates a real application of the model for the TSO–TSO (transmission system operator) cross-border operation, analyzing the specific policy context and proposing a test case for a coordinated power flow simulation. The results show the feasibility of performing the distributed calculation remotely, keeping the overall simulation times only a few times slower than locally.

scholarly journals Voltage Instability Analysis Using Mipower

2020 ◽  
pp. 220-225
Keyword(s):  
Power Factor ◽  
Power Flow ◽  
Flow Analysis ◽  
Minimum Cost ◽  
Load Flow ◽  
Instability Analysis ◽  
Voltage Instability ◽  
Load Flow Analysis ◽  
Newton Raphson ◽  
Raphson Method

Load Flow Analysis helps in error free operation of power system and also useful in forecasting the required equipment for expansion of the system. By forecasting the magnitude of the supply required along with effects caused by single or multiple defects in the system and calculating the magnitude of errors, it is very easy to compensate them using various techniques with minimum cost and effort. It means before installation the favorable sites and size of the infrastructure used are determined to maintain the power factor in the system. Here Power Flow Analysis is performed using Newton Raphson method. This method is used in solving power flow studies of various number of busesunder various conditions. In any network there will be undesired rise or drop or dissipation of voltage. Voltage instability decreases the efficiency of the system and also damages the equipment used. Hence voltage instability analysis is performed and magnitude of the instability is calculated and compensated using various techniques. Here we performed Load Flow Analysis on a 5bus system and Voltage Instability Analysis is also performed to the same with necessary outputs.[7]

Power Flow Investigation Using Cubic Spline Function a Case Study

2018 ◽  
Vol 7 (4) ◽  
pp. 1-16 ◽  
Author(s):  
Shabbiruddin ◽  
Karma Sonam Sherpa ◽  
Sandeep Chakravorty ◽  
Amitava Ray
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Spline Function ◽  
Electrical Power ◽  
Flow Analysis ◽  
Cubic Spline ◽  
Load Flow ◽  
Electrical Power Systems ◽  
Flow Investigation ◽  
Cubic Spline Function

This article presents an approach using cubic spline function to study Load Flow with a view to acquiring a reliable convergence in the Bus System. The solution of the power flow is one of the extreme problems in Electrical Power Systems. The prime objective of power flow analysis is to find the magnitude and phase angle of voltage at each bus. Conventional methods for solving the load flow problems are iterative in nature, and are computed using the Newton-Raphson, Gauss-Seidel and Fast Decoupled method. To build this method, this paper used cubic spline function. This approach can be considered as a ‘two stage' iterative method. To accredit the proposed method load flow study is carried out in IEEE-30 bus systems.

scholarly journals A Flexible Top-Down Data-Driven Stochastic Model for Synthetic Load Profiles Generation

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 269
Author(s):  
Enrico Dalla Maria ◽  
Mattia Secchi ◽  
David Macii
Keyword(s):  
Stochastic Model ◽  
Power Flow ◽  
Distribution Systems ◽  
Control Strategies ◽  
Flow Analysis ◽  
Gaussian Mixture Models ◽  
Gaussian Mixture ◽  
Operating Conditions ◽  
Time Varying ◽  
Top Down

The study of the behavior of smart distribution systems under increasingly dynamic operating conditions requires realistic and time-varying load profiles to run comprehensive and accurate simulations of power flow analysis, system state estimation and optimal control strategies. However, due to the limited availability of experimental data, synthetic load profiles with flexible duration and time resolution are often needed to this purpose. In this paper, a top-down stochastic model is proposed to generate an arbitrary amount of synthetic load profiles associated with different kinds of users exhibiting a common average daily pattern. The groups of users are identified through a preliminary Ward’s hierarchical clustering. For each cluster and each season of the year, a time-inhomogeneous Markov chain is built, and its parameters are estimated by using the available data. The states of the chain correspond to equiprobable intervals, which are then mapped to a time-varying power consumption range, depending on the statistical distribution of the load profiles at different times of the day. Such distributions are regarded as Gaussian Mixture Models (GMM). Compared with other top-down approaches reported in the scientific literature, the joint use of GMM models and time-inhomogeneous Markov chains is rather novel. Furthermore, it is flexible enough to be used in different contexts and with different temporal resolution, while keeping the number of states and the computational burden reasonable. The good agreement between synthetic and original load profiles in terms of both time series similarity and consistency of the respective probability density functions was validated by using three different data sets with different characteristics. In most cases, the median values of synthetic profiles’ mean and standard deviation differ from those of the original reference distributions by no more than ±10% both within a typical day of each season and within the population of a given cluster, although with some significant outliers.

scholarly journals Power Flow Regulation by UPFC in Networks with Voltage Dependent Loads

2020 ◽  
Vol 8 (6) ◽  
pp. 925-932
Keyword(s):  
Power Flow ◽  
Flow Analysis ◽  
Flow Regulation ◽  
Load Flow ◽  
Constant Current ◽  
Voltage Source ◽  
Unified Power Flow Controller ◽  
Flow Equations ◽  
Load Flow Analysis ◽  
Voltage Dependent

In this paper calculations are made to find out the power flow regulation capabilities of Unified Power Flow Controller (UPFC) in load flow analysis with loads which are voltage dependent. New equations for load flow analysis are developed that includes the models of voltage sensitive loads and voltage sources model of UPFC. Newton Raphson algorithm is used to solve the power flow equations of the network. UPFC voltage source model when included in the power equations has unique advantages over other modeling approaches. Analysis is done for two types of Loads. In the first analysis Constant current, Constant Power and Constant Impedance type of loads are examined. In the second analysis Composite loads are analyzed. The results of analysis on standard 5 bus system is presented here as a case study.

Sign in / Sign up

Export Citation Format

Share Document