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.

Power transfer allocation for open access using graph theory-fundamentals and applications in systems without loopflow

Abstract: In this paper, graph theory is used to calculate the contributions of individual generators and loads to line flows and the real power transfer between individual generators and loads that are significant to transmission open access. Related lemmas are proved which present necessary conditions required by the method. Based on AC load flow solution a novel method is suggested which can decide downstream and upstream power flow tracing paths very fast and can calculate the contribution factors of generations and loads to the line flows efficiently. The power transfer between generators and loads can also be determined. The suggested method is suitable for both active and reactive power tracings of real power systems.

The Holomorphic Embedding Load Flow method

Abstract: The Holomorphic Embedding Load Flow is a novel general-purpose method for solving the steady state equations of power systems. Based on the techniques of Complex Analysis, it has been granted two US Patents. Experience has proven it is performant and competitive with respect established iterative methods, but its main practical features are that it is non-iterative and deterministic, yielding the correct solution when it exists and, conversely, unequivocally signaling voltage collapse when it does not. This paper reviews the embedded load flow method and highlights the technological breakthroughs that it enables: reliable real-time applications based on unsupervised exploratory load flows, such as Contingency Analysis, OPF, Limit-Violations solvers, and Restoration plan builders. We also report on the experience with the method in the implementation of several real-time EMS products now operating at large utilities.

A Steady-State Voltage Stability Analysis of Power Systems With High Penetrations of Wind

Abstract: As wind generation begins to contribute significantly to power systems, the need arises to assess the impact of this new source of variable generation on the stability of the system. This work provides a detailed methodology to assess the impact of wind generation on the voltage stability of a power system. It will also demonstrate the value of using time-series ac power flow analysis techniques in assessing the behavior of a power system. Traditional methods are insufficient in describing the nature of wind for steady-state analyses, and as such, a new methodology is presented to address this issue. Using this methodology, this paper will show how the voltage stability margin of the power system can be increased through the proper implementation of voltage control strategies in wind turbines.

Hierarchical Control of Hybrid Energy Storage System in DC Microgrids

Abstract: Hybridization of energy storages (ESs) with different characteristics takes advantages of all ESs. Centralized control with high-/low-pass filter (LPF) for system net power decomposition and ESs' power dispatch is usually implemented in hybrid ES system (HESS). In this paper, hierarchical control of HESS, composed of both centralized and distributed control, is proposed to enhance system reliability. The conventional HESS centralized control is refined with implementations of online iteration, secondary voltage regulation, and autonomous state-of-charge (SoC) recovery. ESs' power references are iteratively generated to maximize the utilization of ES ramp rates and power capacities. Secondary voltage regulation and autonomous SoC recovery are applied to minimize bus voltage deviation and limit slack terminal SoC variation, respectively. In case of communication failure, a novel algorithm for HESS distributed control is proposed to retain system operation. Bus voltage is regarded as the global indicator for system power balance, and droop relationships are imposed for ES control. System net power decomposition and ESs' power dispatch are realized with localized LPFs. SoC recovery in distributed control is implemented by tuning the threshold voltage of a slack terminal. A laboratory-scale dc microgrid is developed to verify the proposed hierarchical control of HESS.

Computer Analysis of Power Systems

Abstract: This book describes the main computer modelling techniques that constitute the framework of modern power system analysis. After describing the main computational and transmission system developments influencing power system analysis, the book covers load or power flow, AC system faults, and the electromechanical behavior of power systems. Dynamic models of power system plants and their use in multi-machine transient stability analysis are discussed, and chapters also cover the electromagnetic transients program, harmonic flow analysis, and power system security and optimization analysis. Recent advances in interactive power system analysis and developments in computer graphics are also presented.