Parameter Identification of Asynchronous Load Nodes

Abstract

Asynchronous loads (AL), because of their low negative-sequence resistance, produce the effect of reduced unbalance at their connection points. Therefore, proper modeling of unbalanced load flows in power supply systems requires properly accounting for AL. Adequate models of the induction motor can be realized in the phase frame of reference. The effective use of such models is possible only if accurate data on the parameters of induction motor equivalent circuits for positive and negative sequences are available. Our analysis shows that the techniques used to determine these parameters on the basis of reference data can yield markedly disparate results. It is possible to overcome this difficulty by applying parameter identification methods that use the phase frame of reference. The paper proposes a technique for parameter identification of models of individual induction motors and asynchronous load nodes. The results of computer-aided simulation allow us to conclude that by using parameter identification, we can obtain an equivalent model of an asynchronous load node, and such a model provides high accuracy for both balanced and unbalanced load flow analysis. By varying load flow parameters, we demonstrate that the model proves valid over a wide range of their values. We have proposed a technique for the identification of asynchronous load nodes with such asynchronous loads, including electrical drives equipped with static frequency converters. With the aid of the AL identification models proposed in this paper, it is possible to solve the following practical tasks of management of electric power systems: increasing the accuracy of modeling their operating conditions; making informed decisions when taking measures to reduce unbalance in power grids while accounting for the balancing adjustment effect of AL.

Comparison of Differential Evolution and Nelder–Mead Algorithms for Identification of Line-Start Permanent Magnet Synchronous Motor Parameters

“…In the case that the motor constructive parameters are unknown, there are several approaches for determining equivalent circuits parameters applicable for IMs [27][28][29][30][31][32][33] and LSPMSMs [25,26,34,35]: (1) steady-state experiments, such as no-load tests, locked rotor tests, etc., allow individual motor parameters to be determined [25]; (2) computer-aided identification algorithms make it possible to use the transient response to estimate multiple motor parameters, as explained in [34].…”

Modeling the Effects of Electromagnetic Interference from Multi-Wire Traction Networks on Pipelines

“…Moreover, the considered works do not present a unified procedure for determining the induced voltage on different parts of structures and the current flowing through the pipeline. Such a procedure could be implemented based on methods that model the behavior of electric power systems in phase coordinates, as described in [34][35][36]. In the following sections, we present the development of this procedure and the results of studies aimed at modeling the effects of electromagnetic interference from multi-wire traction networks and power lines on pipelines.…”

“…If lines affected by influences are included in the individual LEC, then solving the equations will determine the induced voltage [36].…”