Load Flow Analysis Of Distribution System Research Articles

Multiple-node model of wind turbine generating system for unbalanced distribution system load flow analysis

This paper discusses a method to integrate a wind turbine generating system (WTGS) into a three-phase unbalanced distribution system load flow (DSLF) analysis. The proposed method is based on the single-phase multiple-node model. In the present work, the single-phase multiple-node model is extended to a three-phase multiple-node model to facilitate the load flow analysis of a three-phase unbalanced power system network. The multiple-node model (i.e., three-node model) will only modify the load flow analysis by introducing two lines and two load buses to the distribution system network where the WTGS is installed. Thus, a standard three-phase load flow program can be employed to compute the unknown quantities in the DSLF problem formulation. The proposed method is verified by incorporating the model into the load flow analysis of three-phase distribution networks. The investigation uses two representative distribution networks (i.e., 19-bus and 25-bus networks). The results of the study confirm the validity of the proposed method.

Two-port network model of wind turbine generator for three-phase unbalanced distribution system load flow analysis

An unbalanced electric power system can occur due to unequal lines and/or loads in each phase of the system. For a system with a high level of unbalance, the assumption that the system is balanced becomes incorrect. For a case like this, the system must be analyzed using three-phase approaches because single-phase analysis techniques can no longer be used to obtain accurate results. Therefore, the development of three-phase models of all components of the electric power system, including the wind turbine generating system (WTGS), is very important so that the system can properly be analyzed and its performance can correctly be evaluated. This paper proposes a method to incorporate WTGS in a three-phase load flow analysis of an unbalanced distribution system. The proposed method is based on the previously published single-phase two-port network model. In this paper, the single-phase two-port network model is modified and extended so that it can be applied to unbalanced systems. The model is then included in the three-phase distribution system load flow (DSLF) analysis. The proposed method is validated using 12-node and 19-node distribution systems.

A new method to incorporate three-phase power transformer model into distribution system load flow analysis

This paper proposes a new and simple method to incorporate three-phase power transformer model into distribution system load flow (DSLF) analysis. The objective of the present work is to find a robust and efficient technique for modeling and integrating power transformer in the DSLF analysis. The proposed transformer model is derived based on nodal admittance matrix and formulated by using the symmetrical component theory. Load flow formulation in terms of branch currents and nodal voltages is also proposed in this paper to enable integrating the model into the DSLF analysis. Singularity that makes the calculations in forward/backward sweep (FBS) algorithm is difficult to be carried out. It can be avoided in the method. The proposed model is verified by using the standard IEEE test system.

A new method to incorporate three-phase power transformer model into distribution system load flow analysis

A new method to incorporate three-phase power transformer model into distribution system load flow analysis

Applied machine learning in wind speed prediction and loss minimization in unbalanced radial distribution system

ABSTRACT Environmental parameter consideration has always prompted wind power to be used as renewable energy. However, the biggest challenge lies in wind energy integration to the power grid due to wind intermittency. Wind speed or wind power forecasting is one of the approach to manage this intermittency. Numerous prediction methods have been reported in previous literatures over few years. In this work, multivariate wind speed forecasting using Machine Learning framework in a python environment is executed. Several statistical models and neural network models are examined to best predict the wind speed of Surat, India [22.2587° N, 71.1924° E]. The model efficiency is tested in terms of measurements of correlation factors and Mean Absolute Error values. The predicted wind speed value is further considered for the power generation from the wind farm and integrated to the distribution system. Load Impedance Matrix method is implemented for Distribution System Load Flow analysis for being robust and simple with single-step computation. IEEE-19 bus and IEEE-25 bus-unbalanced radial distribution systems are considered for finding the power losses in the branches with wind power as Distributed Generation. An efficient and effective optimization technique, Teaching Learning-Based Optimization, is used to obtain the optimal location and capacity of Distributed Generation to minimize the power loss in the distribution lines.

Two-port network model of fixed-speed wind turbine generator for distribution system load flow analysis

Load flow analysis has always been used in determining the steady-state operation of an electric power or distribution system. For conventional power system without wind turbine generator, the method for load flow analysis has been well established. However, for modern system embedded with wind turbine generator, the investigation of analysis method is still an active research area. This paper proposed a new method to integrate fixed-speed wind turbine generator into distribution system load flow analysis. The proposed method is derived based on two-port network theory where the parameters of induction generator of the wind turbine generator are embedded in general constants of the two-port network. The proposed method has been tested and verified using a representative electric distribution system.

DSPFAP: Distribution systems power flow analysis package using Matlab graphical user interface (GUI)

AbstractThis paper describes a software package whose purpose is to provide a tool to be used for load flow analysis in Power System Analysis courses. The software package which is called Distribution Systems Power Flow Analysis Package (DSPFAP) uses the graphical user interface (GUI) capabilities of Matlab. The main advantage of the developed package is that the load flow analysis can be achieved in both transmission and distribution levels. The package facilitates different forward/backward sweep‐based algorithms to be used for the distribution systems and conventional Newton–Raphson, Gauss–Seidel algorithms for the transmission system load flow analysis. In addition to that, effect of voltage dependent load models and effects of DGs on the distribution systems load flow solution can be investigated using the program. It is also possible to use conventional algorithms for distribution system load flow analysis in the package. The package can freely be downloaded from the website: http://www.gyte.edu.tr/Dosya/102/power/. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 1–13, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20209

Distribution Systems Forward/Backward Sweep-based Power Flow Algorithms: A Review and Comparison Study

Because of different characteristic features of distribution networks, such as radial structure and high R/X ratio, distribution system load flow analysis differs significantly from transmission systems. Accordingly, a number of methods that are specially designed for the solution of the power flow problem in radial distribution systems are found in the literature. Most of the developed methods are based on the forward/backward sweep processes for the solution of the ladder networks. In this article, various distribution system load flow algorithms, based on the forward/backward sweeps, are reviewed, and their convergence ability is quantitatively evaluated for different loading conditions, R/X ratios, and sub-station voltage levels. Moreover, the effects of static load modeling on the convergence characteristics of algorithms are also investigated.

Data structure for radial distribution system load flow analysis

Owing to the radial nature and high R/X ratio, radial distribution systems (RDS) employ a special recursive technique for distribution load flow (DLF). An efficient method for DLF plays a critical role in automation algorithms of RDS whose scope encompasses fault isolation, network reconfiguration and service restoration. The ability of automation algorithms to handle these complex tasks that require frequent topology changes in the RDS demands a dynamic topology processor based on a well-defined data structure. The purpose of this paper is to formulate a dynamic data structure (DDS) and an algorithm that generates the DDS of the RDS as an R-tree. The proposed DDS algorithm generates the DDS and is used as a topology processor in the DLF algorithm. The resulting DLF algorithm is computationally efficient and can handle rapidly changing topology by updating the R-tree. The pseudocodes for the DDS algorithm and the overall recursive algorithm for DLF are presented. Various RDS have been tested with the proposed method and the results demonstrate its efficiency over other known methods of DLF.

Distribution system load flow calculation with microcomputer implementation

In this paper, a load flow calculation method for a radial distribution system is developed. The proposed method, which is derived from a Z-loop analysis, is very straightforward and simple without unnecessary mathematical approximations. It requires the same storage size as the Gauss-Seidel method, but less computation time than the conventional Newton-Raphson program. It is attractive for accurate or approximate off-line and on-line routines and contingency calculations for radial systems. The proposed solution algorithm can be implemented directly and efficiently into microcomputers with limited storage capacities. To examine the effectiveness, three normal radial distribution systems for 13-, 22-, and 58-bus systems were studied by the proposed method, and the convergence characteristics of a 43-bus ill-conditioned system are compared with the Newton-Raphson method. The proposed method is recommended for distribution system load flow analysis.