Marek Loboda

Essential requirements for earthing system determining the efficiency of lightning protection

One of the important factors in designing an efficient lightning protection (LPS) system is to determine if a considered object, system or installation is exposed or not to electromagnetic interference. An exposed system or installation is vulnerable to unwanted sources of current and voltage including the most severe interference sources, which are lightning currents with wide range of statistical parameters.

Transient behaviour and parameters of earth electrodes designed for lightning protection system (LPS) in focus of the requirements of new edition of IEC (EN) 62305 standard

In the paper are described general factors influencing the transient behavior of LPS earth electrodes in case of lightning current dissipation in soil. These factors should be taken into account by designers of LPS, however, in the new series of the IEC(EN) 62305 lightning protection standards there is no information addressed to this specific problem. The intention expressed in this paper was to give the short description of parameters, which should be taken into account when determining the effective dimensioning and configuration of LPS earth electrodes. The simplified methodology of their transient parameters assessment which might be useful for engineering applications is also described.

Lightning location with the two networks perun and linet in Poland

This contribution presents a comparison of lightning data for Poland, measured with two different networks. The first is a Safir 3000 system (PERUN), operated by the Institute of Meteorology and Water Management. The second system is LINET as part of a European network, operated by nowcast GmbH in cooperation with the Physics Department of the University of Munich. PERUN utilizes VHF interferometry for the detection of cloud lightning, while ground strokes are located with LF sensors and TOA technology. LINET exploits the VLF/LF band for the detection of both cloud lightning and ground strokes. The comparison of the network data is interesting for two reasons: first, the performance of the networks can be compared and relative differences enlighten the quality of lightning parameters, consoli-dating earlier comparisons on a statistically broader basis; second, since different band widths are used and, thus, different discharge steps are measured, some insight into the physics of lightning is enabled. In particular, new information about cloud lightning can be derived.

Preliminary study of lightning exposure of double-circuit 400 kV transmission line with special design of towers in Poland/Lithuania

The paper describes main characteristics of new 400 kV transmission line located in Poland to Lithuania which is important part of Baltic Ring - EU Power grid project. The main features of the line related to lightning hazard due to unusual height of towers influencing its lightning exposure are described. Preliminary analyses of expected frequency of lightning direct and nearby strikes to the line and to substations located on both ends of the line are presented. Special attention is paid to the lightning hazard of HVDC “back-to-back” convertor station located on Lithuania side and its sensitive electronic equipment. Some data of lightning activity in area of line location are used form LINET lightning location system data base to assess possible lightning overvoltages frequency in the line and their magnitude taking into account of measurements results of towers earthing system parameters.

Investigations of earthing components corrosion in different climatic conditions

The paper is addressed to studies of earthing system components corrosion in different climatic conditions based on comparative field tests results from Poland, North Africa and China. The paper is continuation of the paper presented at ICLP 2010 in Cagliari, and contains discussion and analyses of new field corrosion tests and observations performed in Sudan, which is located in warm, dry (arid), desert climate.

Evaluation of multiple ground flash charge structure from electric field measurements using the local Lightning Detection Network in region of Warsaw

During three summer months, i. e., from 16 June 2009 to 16 September 2009 the Local Lightning Detection Network (LLDN) set up in the Warsaw region was successfully operated. For this period it was able to distinguish 16 events of multiple cloud-to-ground (CG) lightning flashes recorded simultaneously by all six stations, which recorded E field changes caused by the same flash. Using special software packet developed for purpose of E field analysis of recorded E field changes gave a new possibility to calculate three dimensional location of each point electric charge source, i.e., by the estimated value of its parameters x, y, z in local set of the Cartesian coordinates, and also the magnitude of the electric charge, Q, involved in particular return stroke or continuing current of the considered CG lightning discharge. Some examples of such spatial and time development of recorded multiple CG flashes initiated in different meteorological situation/thunderclouds are presented and discussed in the paper.