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.

Wide-Area Measurement-Based Voltage Stability Indicators by Modified Coupled Single-Port Models

Abstract: The coupled single-port model has been proposed recently for wide-area measurement-based voltage stability assessment. This concept relies in decoupling a mesh power grid into the local single-port circuit coupled with an extra impedance. However, underestimations in this approach have been observed in simulation studies. In this paper, a modified coupled single-port model is proposed. Based on real-time PMU measurements of individual load bus, the reactive power response used in the extended Ward-type equivalent will be explored to compensate the reactive power mismatch in the existing model. In addition, a mitigation factor is introduced to modify the Thevenin equivalent parameter of the existing model. Due to the simplicity of the proposed model, several voltage stability indicators can be applied with slight modifications. Simulations on various IEEE test systems are presented to validate the accuracy of the proposed method.

Active Power Control of DFIG-Based Wind Farm for Improvement of Transient Stability of Power Systems

Abstract: This paper proposes a method to control the output power of a wind farm with the aim of improving the transient stability of a multi-machine power system. Doubly fed induction generators (DFIG) are considered for the variable speed wind farms. The variation of the frequency of the DFIG terminal bus is used to modulate the torque reference and thus the output power of the DFIG in the post-disturbance condition. This in turn modifies the electrical power of the nearby alternators and causes improvement of stability. The proposed control technique is validated in WSCC 3-machine 9-bus system and IEEE 16-machine 68-bus system. The study is carried out in PSCAD/EMTDC as well as in MATLAB platforms.

State Calculation of Power Systems From Line Flow Measurements

Abstract: This paper describes a new and efficient method for computing a real-time load flow solution of a power system network. The use of line flow measurements is proposed and it is shown that this measurement scheme shows superiority in speed, accuracy and numerical behavior together with advantages in error detection and identification.

Bound Estimates of the Severity of Line Outages in Power System Contingency Analysis and Ranking

Abstract: The effect of line outages on the real power flows of a system is analyzed using the DC load flow model. It is shown that the effect of the out4ge of line jk on the power flow of an arbitrary line lm can be bounded above and below by a series of progressively tighter values which in the limit correspond to the exact DC load flow solution. The calculation of these bound estimates on the contingency line flows is progressively more computationally demanding as the limits tighten, however, the simple to compute bounds, although more conservative, still serve to filter out a large portion of the non-critical contingencies. The remaining few potentially critical outages can then be ranked and analyzed through the full DC load flow.