Dynamic Modeling of Power Systems Experiencing Faults in Transmission/Distribution Networks

Abstract

In this paper we address some shortcomings in existing nonlinear dynamic models of power system experiencing symmetrical and unsymmetrical faults in their transmission/distribution networks. The shortcomings relate to: 1) approximations relating to stator dynamics, internal voltage of the positive sequence network and the dynamics of the negative and zero sequence networks, and 2) existing models are time -variant, which may not be suitable for system studies such as stability and fault detection studies that require time invariant model. The approximations outlined in 1) adversely affect the modeling accuracy, especially that of the system response during the period immediately after the occurrence of faults. We present in this paper a full fault-dependent time-invariant dynamical model of power systems experiencing symmetrical and unsymmetrical faults in their transmission/distribution networks and verify it through simulation studies mimicking real life scenarios. IEEE 30 bus power system is considered as the study case. The simulation results are compared to Matlab's "SimPower" and PSCAD/EMTDC software packages.

A Matlab-Based Simulation Tool For The Analysis Of Unsymmetrical Power System Transients In Large Networks

“…The relations in (4) and (5) hold for both currents and voltages. It has been shown in (Saha and Aldeen 2015) that the zero sequence stator quantities vanish in the d/q-coordinates.…”

“…• Three phase power flow calculations (Abdel-Akher et al 2005), (Kamh and Iravani 2010), (Demirok et al 2012), • Assessment of small signal stability (Salim and Ramos 2012), and • Analysis of dynamic transients in transmission networks (Saha and Aldeen, 2015) or distribution level systems (Elizondo et al 2016). The research highlighted above mainly focused on component modeling for three-phase unbalanced dynamic analysis and validating the developed models using commercial simulation tools.…”

Dynamic analysis of multi‐machine multi‐UPFC power systems experiencing transient asymmetrical faults

“…Thus, to consider these harmonics, the simulation step size must adequately decrease, which will cause a significant increase in the simulation time. Thirdly, as the variables are periodic, the simulation results of these programs cannot provide proper insight into the system sensitivities for designing suitable controllers or special protection schemes [8].…”

“…In [8], a time‐invariant dynamical model for power systems based on SNs has been proposed. It is well known that to solve the negative‐sequence equations of a synchronous machine, double frequency currents are produced in the rotor windings.…”

“…It is well known that to solve the negative‐sequence equations of a synchronous machine, double frequency currents are produced in the rotor windings. As described by [8], machine equations are solved in the synchronous reference frame of clockwise rotations. Therefore, the mutual inductances between the rotor DQ ‐axis windings and the equivalent DQ ‐axis windings of the synchronous machine (in the DQ ‐reference frame with an angular speed of ) are not time‐invariant.…”