Arc Extinguishing Method of SPD Type 1

Lightning strikes create surge currents which generate overvoltages in the power distribution and data transmission networks. The spark gap surge protective device (SPD) Type 1 diverts high surge current harmlessly to the ground and limits overvoltage to acceptable values. The present paper aims to present the investigations on the spark gap technology and demonstrates the arc extinguishing method on the surge protective device?s performances. Firstly, the association of the spark-gap with an extinguisher device will be presented. In a second stage, experimental and numerical results of the current density, the pressure, and the temperature of the arc during its propagation will be shown. Both the calculations and measurements have been done for a 10/350 ?s pulse and various peaks current.     

A Modified Version of the Rolling Sphere Method

The calculation of the striking distance can estimate the probability of lightning strike on a structure and thereby evaluate the effectiveness of a lightning protection system (LPS). The dimensioning and the positioning of air-termination on structures is often performed with the Rolling Sphere Method (RSM). RSM originated from the electric power transmission industry and is based on the well-known Electrogeometric Model (EGM). The EGM relates striking distance to the prospective peak stroke current. To apply this technique, an imaginary sphere is rolled over the structure. All surface contact points are deemed to require protection, whilst the unaffected volumes are deemed to be protected. The main drawback of this method is that it disregards the upward leaders? development and assumes the same probability for attachment to the ground, to a structure, and to a LPS. The proposed model is based on physical phenomena leading to the formation and the development of positive upward leader in the field produced by the negative downward leader charge distribution and by some other competing upward leaders. Its purpose is to develop a 3-D numerical model in order to improve the interception efficiency of the Lightning Protection System.     

Silicon Recovery from Kerf Slurry Waste: a Review of Current Status and Perspective

Silicon - Over the past years, the photovoltaics (PV) industry has been experiencing a strong economic growth worldwide. This development is due to an increasing demand for PV modules which is...