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.

Cascading Failure Analysis for Indian Power Grid

Abstract: Major power grid blackouts in various parts of the world are characterized by voltage collapse. This paper studies the blackout case in the Indian power grid due to voltage collapse in the inter-regional corridor. First, the computer simulation models are tuned to match responses from the phasor measurement units at various locations in the grid. The inter-area mode with the frequency of 0.3 and 0.5 Hz with reduced damping were observed and resulted due to switching actions that occurred during the disturbance. This paper simulates the complex power grid network for various loading conditions of Northern region using power system simulator for engineering. Further, the system variables are analyzed using Prony method to estimate the inter-area mode for different NR loading conditions. The eigen values associated with the 0.3 Hz mode depict the movement from open left half plane into open right half plane with a slight increase in the parameter indicating “hopf bifurcation.” This paper also discusses the maximum loading capacity for the inter-regional lines in-order avoid loss of small signal stability, and highlights the use of real time phasor measurement unit measurements in-order to estimate and track the oscillatory modes.

Integration of geomagnetic disturbance modeling into the power flow: A methodology for large-scale system studies

Abstract: This paper presents a methodology for integrated power flow modeling of the impact of geomagnetic disturbances (GMDs) on power system voltage stability. GMDs cause quasi-dc, geomagnetically induced currents (GICs) in the transformers and transmission lines, which in turn cause saturation of the high voltage transformers, greatly increasing their reactive power consumption. GICs can be calculated using standard power flow modeling parameters such as line resistance, augmented with several GIC specific fields including substation geographic coordinates and grounding resistance, transformer configuration, and transformer coil winding resistances. When exact values are not available, estimated quantities can be used. By then integrating GIC into power flow analysis, the changes in reactive power losses and bus voltages can be quantified to assess the risk of voltage instability and large-scale voltage collapse. An example calculation is provided for a North American Eastern Interconnect model.

Analysis of asymmetrical faults in power systems using dynamic phasors

Abstract: Summary form only given, as follows. This paper presents application of the dynamic phasor modeling technique to unbalanced polyphase power systems. The proposed technique is a polyphase generalization of the dynamic phasor approach, and it is applicable to nonlinear power system models. In a steady-state, the dynamic phasors reduce to standard phasors from AC circuit theory. The technique produces results that are very close to those obtained from time-domain simulations. Simulations in terms of dynamic phasors typically allow larger integration steps than the standard time-domain formulation. The authors present simulations of unbalanced faults involving a three-phase synchronous generator connected to an infinite bus through a transmission line, and demonstrate that models based on dynamic phasors provide very accurate descriptions of observed transients.

A model of voltage collapse in electric power systems

Abstract: Voltage collapse dynamics were previously modeled by the movement of the system state along a particular trajectory at a saddle node bifurcation. The authors apply this voltage collapse model to a simple three-bus power system model which includes a dynamic induction motor model. Voltage collapse dynamics are demonstrated, showing that the model can be applied to a simple power system. Approximate calculations suggest that load reactive power balance is an important factor in this collapse. >

A Range Arithmetic-Based Optimization Model for Power Flow Analysis Under Interval Uncertainty

Abstract: This paper presents a novel framework based on range arithmetic for solving power flow problems whose input data are specified within real compact intervals. Reliable interval bounds are computed for the power flow problem, which is represented as an optimization model with complementary constraints to properly represent generator bus voltage controls, including reactive power limits and voltage recovery processes. It is demonstrated that the lower and upper bounds of the power flow solutions can be obtained by solving two determinate optimization problems. Several numerical results are presented and discussed, demonstrating the effectiveness of the proposed methodology and comparing it to a previously proposed affine arithmetic based solution approach.