Experimental study of HBC fuses working at short and medium pre-arcing times

Abstract

Pre-arcing stage is the first working step in high breaking capacity (HBC) fuse operation and affects the following step, namely, the arcing step. We have performed realistic HBC fuse tests for short (<10 ms) and medium (>10 ms) pre-arcing times by varying the phase angle of the electrical fault (defined as the phase angle of the fault current once the supplied voltage is applied to the fuse) in the range from 0° to 160°, for two values of the power factor (cosφ ∼ 0.9 and cosφ ∼ 0.1). Experimental values of the pre-arcing time and the arcing time (tarc) are given for tprearc/tarc ≲ 1 to ∼4.2, and discussed from the energetic point of view by taking into account the inductive source term. The adiabatic assumption classically used in the modelling is also examined. The influence of the pre-arcing step on the arcing step is analysed by means of the Joule integral, the energy dissipated in the fuse and the mass and length of the fulgurite.

Electric fuses operation, a review: 1. Pre-arcing period

“…These calculated trends are reinforced by practical tests whose results are close to the calculations as quoted in [37]. These two main electrical features -the closing angle and the power factor -have been investigated in [39] by means of an experimentally approach and in [38] by considering an adiabatic heating of the fuse element, the pre-arcing period being depicted from a set of common electrical equations. From this latter we show in figure 14(b) the dependence between the maximum pre-arcing energy and the circuit power factor with the corresponding optimal value for the closing angle.…”

Simulations and Measurements of the Pre-Arcing Times in HBC Fuses Under Typical Electric Faults

“…The experimental test device built from a 100kVA true single-phase transformer has been designed to reproduce the whole fuse operation in fault conditions similar to the industrial test conditions. The experimental device and the test operation have been described in previous works by Bussière et al [6] and Memiaghe et al [7]. The main electrical parameters of the measurements are recalled hereafter.…”

“…The fuse-link length is L=66 mm and its cross-section area is l×e= 1×0.105 mm 2 . For the experiments, the fuse element (designed to reproduce elementary phenomenon occurring in industrial fuses) is introduced in the circuit network by means of an experimental fuse cell as depicted in [6].…”

“…In the past many authors were interested in the optimization of fuse performance with special reference to the pre-arcing. Some studies were carried out under AC supply [2][3][4][5][6], others under DC supply [2,5]. The main tasks of these investigations were to understand in which manner electrical characteristics of a circuit network play a role in the fuse performance and to link the electrical energy dissipation of the fuse to the prediction of pre-arcing times.…”

Influence of System Parameters on Fuse Protection Use in Regenerative DC Drives

“…Like many other devices the fuse has undergone considerable evolution since those early days [1]. The modern High Breaking Capacity (h.b.c) fuse provides economical and reliable protection against over current faults in modern electrical systems.…”