Digital analysis and development of ride-through capability of ac contactor with respect to voltage sag characteristics

Abstract

This paper presents the development of digital simulator tool for sensitivity analysis of ac contactor with respect to voltage sag characteristics. The simulator tool allows varying of the sag characteristics for the purpose of evaluating the behavior of ac contactor under very worst conditions of voltage sags. Describing voltage sag characteristics by their magnitude and duration only without consideration of other parameters is no longer suitable to fully assess the equipments sensitivity. Therefore, this paper presents the necessity to include the point-on-wave of sag initiation and phase shift of sag to explain the sensitivity of ac contactor during sags. From the simulation results, the ride through capability curve is constructed to identify ac contactor sensitivity levels. The curve has demonstrated a rather complex behavior of the ac contactor. By having a simulator tool, ac contactor analysis can be simulated for any type of configurations without having to perform laboratory experiments.

An improved AC electromagnetic contactor model based on EMTP

“…Consequently, the inductance of the air gap is increased (reluctance is decreased). To include the fringing effect, the permeances of air gap inductor were calculated using method in [23,24,26]. The fringing flux paths are illustrated in Fig.…”

“…However, the drawback of MEC is that it generally neglects the effect of fringing flux in air gaps, which causes significant errors. In order to decrease these errors, the concept of the high-fidelity magnetic equivalent circuit (HFMEC) was proposed [24][25][26]. HFMEC takes leakage and fringing flux paths into account and also includes magnetic saturation by derivation of analytical expressions.…”

Load influence on the response of AC-Contactors under power quality disturbances

“…However, the parameter of the point on wave initiation is not included in the model. By this reason, this model is improved several years later by [45], where the dip initiation angle is a user-defined parameter. The results of the simulations presented in [34,45] differ significantly from the experimental results showed by other authors.…”

“…By this reason, this model is improved several years later by [45], where the dip initiation angle is a user-defined parameter. The results of the simulations presented in [34,45] differ significantly from the experimental results showed by other authors. Nevertheless, the simulation models defined in [32,44,51,54] offer voltage tolerance curves for AC-Contactors with a high level of accuracy.…”

A novel simulation of AC magnetic contactor based on electromagnetic transients program

“…Alternatively, a simpler concept of magnetic equivalent circuit (MEC) may be preferable. Such models based on MEC have been proposed in the literature [16–23]. However, the drawback of MEC is that it generally neglects the effect of fringing flux in air gaps, which causes significant error.…”