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.

Controlling generator power

Abstract: A power controller for controlling an engine-driven generator includes a high voltage DC bus interconnecting various power modules. In electrical communication with the DC bus are: a bi-directional DC-DC converter constructed to transfer electrical power from the DC bus to a battery to charge the battery, and from the battery to the DC bus; a rectifier constructed to rectify electrical power from the generator and to supply the rectified power to the DC bus; an invester constructed to convert DC bus electrical power to AC electrical power and to supply the AC power to an output connector; and an AC-DC constructed to convert AC electrical power, supplied via an input connector, to DC bus electrical power. The controller may be employed in a power supply on a mobile vehicle or boat, for example. The power modules of the controller cooperate in various combinations to provide a wide variety of power transfer functions.

Assessment of Robustness of Power Systems From a Network Perspective

Abstract: In this paper, we study the robustness assessment of power systems from a network perspective. Based on Kirchhoff's laws and the properties of network elements, and combining with a complex network structure, we propose a model that generates power flow information given the electricity consumption and generation information. It has been widely known that large scale blackouts are the result of a series of cascading failures triggered by the malfunctioning of specific critical components. Power systems could be more robust if there were fewer such critical components or the network configuration was suitably designed. The percentage of unserved nodes (PUN) caused by a failed component and the percentage of noncritical links (PNL) that will not cause severe damage are used to provide quantitative indication of a power system's robustness. We assess robustness of the IEEE 118 Bus, Northern European Grid and some synthesized networks. The influence of network structure and location of generators are explored. Simulation results show that the connection with short average shortest path length can significantly reduce a power system's robustness, and that the system with lower generator resistance has better robustness with a given network structure. We also propose a new metric based on node-generator distance (DG) for measuring the accessibility of generators in a power network which is shown to affect robustness significantly.

Mitigating cascading failures in interdependent power grids and communication networks

Abstract: We study the interdependency between the power grid and the communication network used to control the grid. A communication node depends on the power grid in order to receive power for operation, and a power node depends on the communication network in order to receive control signals. We demonstrate that these dependencies can lead to cascading failures, and it is essential to consider the power flow equations for studying the behavior of such interdependent networks. We propose a two-phase control policy to mitigate the cascade of failures. In the first phase, our control policy finds the unavoidable failures that occur due to physical disconnection. In the second phase, our algorithm redistributes the power so that all the connected communication nodes have enough power for operation and no power lines overload. We perform a sensitivity analysis to evaluate the performance of our control policy, and show that our control policy achieves close to optimal yield for many scenarios. This analysis can help design robust interdependent grids and associated control policies.

A Novel Load-Flow Analysis for Stable and Optimized Microgrid Operation

Abstract: This paper proposes a novel load-flow analysis (LFA) algorithm for droop-based islanded microgrids (DBIM). The standard LFA is not applicable for DBIM due to the absence of a node with fixed reference voltage. As the voltage in the islanded microgrid depends on the droop relations, these relations are included as part of the load-flow equations. The proposed LFA is used with particle swarm optimization to select the droop parameters that optimize the reactive power sharing. Voltage compensation terms are also suggested to improve voltage regulation. By using the proposed LFA, a modeling procedure is suggested to check the stability and stabilize the microgrid. The effectiveness of the proposed methods is verified through different simulation studies.

Distributed system and methodology of electrical power regulation, conditioning and distribution on an aircraft

Abstract: A novel system and methodology of electrical power regulation, conditioning and distribution on an aircraft is disclosed. The system comprises an alternator adapted to directly connect to an engine on the aircraft and generate variable frequency AC power, a variable frequency AC bus coupled directly to the alternator, and at least one variable frequency AC load at low performance, coupled to the variable frequency AC bus. At least one bi-directional power converter may be coupled directly to the variable frequency AC bus and adapted to convert the variable frequency AC raw power to a fully regulated adjustable-frequency and adjustable-voltage power to control AC motors and other high performance variable frequency AC loads. A bi-directional power converter is coupled directly to the variable frequency AC bus and adapted to convert the variable frequency AC power generated by the alternator into constant frequency AC power. At least one constant frequency AC load is coupled to a constant frequency AC bus which is in turn coupled between the constant frequency AC load and the bi-directional power converter. A first bi-directional power bus controller is coupled between the bi-directional power converter and the constant frequency AC bus. The system further comprises an AC/DC bi-directional power converter coupled to a DC bus and at least one DC load coupled thereto. A second bi-directional power bus controller is coupled between the AC/DC power converter and the DC bus. The first and second bi-directional controllers provide for the selective and automatic reconfiguration of the flow of power through the system. A novel high-level subsystem interconnection architecture is also disclosed.