Power-flow study

About: Power-flow study is a research topic. Over the lifetime, 8091 publications have been published within this topic receiving 155053 citations. The topic is also known as: load-flow study.

A Generalized Approach to the Load Flow Analysis of AC–DC Hybrid Distribution Systems

Abstract: This paper proposes a unified load flow (LF) model for AC–DC hybrid distribution systems (DSs). The proposed model can be applied in hybrid DSs with mixed configurations for AC/DC buses and AC/DC lines. A new classification of DS buses is also introduced for LF analysis. A set of generic LF equations has been derived based on comprehensive analysis of the possible AC–DC hybrid system configurations. Three binary matrices, which are used as a means of describing the configuration of the AC and DC buses and lines, have been employed in the construction of the unified power equations. These matrices enable a single configuration at a time to be activated in the power equations. The proposed LF model is generic and can be used for both grid-connected and isolated hybrid DSs. The new model has been tested using several case studies of hybrid DSs that include different operational modes for the AC and DC distributed generators. As a means of evaluating the effectiveness and accuracy of the proposed model, the LF solution was compared to the solution produced by PSCAD/EMTDC. A comparison of the results reveals the efficacy of the proposed model.

Modular power supply with multiple and interchangeable output units for AC- and DC-powered equipment

Abstract: The modular power supply of the present invention provides a new device and method for powering multiple portable and/or small devices each requiring an AC or DC current source at one of various low-voltage levels. The invention comprises a main power base that is capable of converting AC power levels in common use internationally into a main low-level DC bus, which may, for example, be 24VDC. The AC input source and the derived DC voltage are then supplied via separate buses to smaller power “blocks” of two distinct designs, one for transforming the AC bus voltage to a low-voltage AC output, and one for converting the DC bus voltage to a low-voltage DC output. The DC blocks are of a common design, but are differentiated in that their respective output voltages are set by a “programming” element. The AC blocks are of a second common design, but are differentiated in that their respective output voltages are set by a “programming” transformer. All of these power “blocks” are of such a physical design that any DC block can only make contact with the DC bus and any AC block can only make contact with the AC bus. All of the blocks share a common output connector type and a common shape. In this way, a certain number of blocks, set by the size and output power of the power base unit, may be chosen from the group of all AC and DC blocks. Such blocks can be interchanged in placement on the power base unit in various permutations so as to meet the AC or DC input requirements of the various equipment that is to be powered by the invention.

Optimal power flow for combined AC and multi-terminal HVDC grids based on VSC converters

Abstract: In this paper, an optimal power flow for combined AC and DC grids is proposed. Several suggested projects to increase the transmission capacity are based on multi-terminal HVDC grids (MTDC). The construction of MTDC leads to major changes in the power flow of the existing grids. The problem description given in this paper considers the main points for power flow in a combined AC and MTDC grid. The AC side is calculated with the full power flow equations. The voltage source converter (VSC) are represented with a model based on two generators, an additional AC node and one connecting line. The VSC losses are calculated with a simple model and the DC line losses are also considered. The optimization could focus on several different goals. The resulting optimal power flow is shown in two different grids. Three different scenarios are presented in a small grid with 10 AC nodes and 5 converter stations. In addition, a combined AC and DC grid based on the IEEE118 test system is used to show a large scale example.

A Review of High-Frequency Power Distribution Systems: For Space, Telecommunication, and Computer Applications

Abstract: High-frequency AC (HFAC) power distribution systems have been the subject of great interest over the last several decades. This paper presents a thorough review of different HFAC power distribution architectures on which the authors have worked in the last 30 years. The review is focused on the HFAC power architectures and topologies for space, telecommunications, and computer applications. Detail of each architecture is given and evaluated in terms of performance specific to each application.

Coherency identification in interconnected power system - an independent component analysis approach

Abstract: Summary form only given. This paper presents a novel approach to the coherency identification technique in interconnected power system using independent component analysis (ICA). The ICA is applied to the generator speed and bus angle data to identify the coherent areas of the system. The results of the application of ICA using simulated data from 16-machine 68-bus system model and on data gathered through U.K. University-based Wide-Area Measurement System are presented. The approach is able to identify the cluster of generators and buses following a disturbance in the system. It is also demonstrated that the approach is robust in the presence of noise in measured signal, which is an important factor to be considered for assessing the effectiveness of any measurement-based technique.