Lightning Protection Equipment Research Articles

Analysis of Thermal Effects for Polymer-Housed Metal-Oxide Surge Arrester Under Multiple Strokes

Multiple strokes are the main factors affecting the safe and stable operation of power equipment. As the core lightning protection equipment, arresters are also frequently thermally collapsed due to multiple strokes. This paper investigates thermal effects of polymer-housed metal-oxide surge arrester (PMOSA) under multiple strokes. The comparative experiments of PMOSA lightning impulse are carried out through multiple strokes of experiment platform, including continuous lightning stroke and multiple strokes. Furthermore, the temperature distribution of the housing surface is obtained by infrared imager for thermal effect analysis. Subsequently, some typical DC parameters are tested to explore the association of impulse aging and thermal effects of the arrester under multiple strokes. Finally, a thermal-electric coupling model (TECM) is constructed to investigate the influence of some factors on the temperature of PMOSA from the perspective of materials and structure. The research in this paper can provide a theory reference and brief data support for improving the heat dissipation performance of arresters under multiple strokes based on structural optimization design and material modification.

A Power Line Lightning Protection Method for Television and Radio Stations

The existing research on lightning protection focuses on risk assessment or equipment selection. There has not been any thorough research about lightning protection including risk assessment for a building in order to identify the risks when selecting lightning protection equipment according to technical requirements and cost optimization. The objective of the current paper is to propose a new risk computational method of damages by lightning for a Television and Radio Station (TRS). The new computational method consists of nine steps for identifying two risk indices, human life loss (R1) and service loss (R2). If the value of R1 is higher than the regulatory limit value RT1 and the value of R2 is higher than the regulatory limit value RT2, the damage risks due to lightning are very serious. Therefore, the TRS is necessary to select lightning protection solutions to reduce these risks. In addition, the paper proposes a six-step procedure for selecting and testing surge protective devices. The proposed calculations are then applied to a real TRS in Vietnam, and some testing results are simulated in Matlab-Simulink.

Basic Technology of Grounding Equipment and Lightning Protection Equipment

Basic Technology of Grounding Equipment and Lightning Protection Equipment

Measurement and analysis of partial lightning currents in a head phantom.

Direct lightning strikes to the human head can lead to various effects, ranging from burnings to death. The biological and physical mechanisms of a direct lightning strike in the human head are not well understood. The aim of this paper is to design an experimental setup to measure the spatial and temporal current distribution during a direct lightning strike to physical head phantoms to establish normative values for personal lightning protection equipment design and testing. We created head phantoms made of agarose, replicating the geometric and dielectric properties of scalp, skull, and intracranial volume. The bases of the three compartments were galvanically contacted via copper electrodes to measure the current per compartment. We used pulse generators to apply aperiodic voltage and current signals that modelled lightning components. Our experiments indicated that the scalp compartment was exposed to the current with a fraction of 80–90%. The brain and skull compartments were exposed between 6–13% and 3–6% of the total measured current respectively. In case of a flashover, most of the current (98–99%) flowed through the discharge channel. Unlike previous theoretical estimates and measurements in technical setups, we observed considerably longer times for the flashover to build up. In our experiments, the time to build up a fully formed flashover varied from approximately 30–700 μs. The observed current patterns in cases without and with flashover provided information on regions of possible damage in the human head. Consequently, we identified the phenomenon of a flashover as a potential mechanism for humans to survive a lightning strike. Our measured current distributions and amplitudes formed the base for normative values, which can be used in later experimental investigations regarding the possibilities of individual lightning protection equipment for humans.

Planning and Design of Lightning Protection Equipment

Planning and Design of Lightning Protection Equipment

Consideration of Lightning Current along a Tall Structure in the Presence of Horizontal Arrangement Grounding

The evaluation of the behaviour of lightning current along a tall structure is becoming an important issue when considering the lightning protection equipment required along a tall structure. This behaviour is affected by the element of the ground reflection factor which has a correlation between the impedance of the ground and the tower. The impedance of the ground is considered for a horizontal grounding arrangement while the impedance of the tower is assumed to be constant. Hence, the ground reflection factor can be given a variable value, whereas most of the existing literature assumes a constant value. When a constant value is entered into a calculation field, an inaccurate result is computed.In this paper, the lightning current along a tall structure under varying values of ground reflection factor and including the effect of the presence of a horizontal grounding arrangement has been considered and the results discussed accordingly. Modelling of the lightning return stroke current along a tall structure was undertaken by entering the calculated variable value of the ground reflection factor. The results indicated that a variable value of the ground reflection factor causes different peak values of the current and wave shape of the lightning current for different positions along a tall structure.

The MOA Live Detection System Based on Wireless Synchronization

The MOA is the main lightning protection equipment in power system, The status is generally monitored by online monitoring and offline test in routine maintenance. Traditional MOA live detection requires a lot of wiring, and has operation problems and safety risks. A new distributed MOA online monitoring wireless measurement is presented in this paper, that is, 433M wireless transmission and GPS clock synchronization technology fulfill distributed wireless synchronization measurement in MOA online monitoring device. Focusing on the design principles, implementation methods and the device composition, it is indicated that the wireless synchronization testing result is same with wired synchronization testing result, which can meet the requirements of MOA online monitoring.

Analysis of Lightning Phenomena for Underground Petroleum Pipeline System

This article presents the lightning phenomena analysis for underground petroleum pipeline system and protection guideline by considering an electrical continuity after a lightning strike to the earth. The result of transient state occur on the pipeline by using mathematical program (ATP-EMTP) to simulate standard waveform 10/350 micro second which will be linked to several dimensions. This study will transform physical characteristics into electrical characteristics such as pipe metal, pipe insulator, conductors in corrosion protection circuit and earth as parameters in the analysis. The result of this simulation found that the transient voltage will rise higher if length is longer and higher than safety allowance of pipe corrosion protection equipment. To limit this over voltage, this study used proper lightning protection equipment characteristics. From the result of simulation and the proper characteristics of lightning protection equipment, the transient voltage was limited follow BS 60950 standard. The result showed that the correct lightning protection equipment will help to reduce damage to asset of petroleum transportation industry from lightning strike.

International comparison of standard systems for impulse current measurement

AbstractThe impulse current test is an important test that is used for the evaluation of lightning protection equipment. The quality of the test greatly depends on the measuring system. Some countries already have their own standard measuring systems. Standard systems are under construction in Japan and Korea. According to the international standard on high‐voltage test techniques, a comparison test is needed to confirm the impulse parameters which have traceability or compatibility with the standard values. Different from intercomparison of impulse voltage measuring systems, Japan and Korea have not conducted an international comparison test for impulse current measuring systems. Now we have jointly conducted a comparison test for impulse current measurement. As a result, it was confirmed that the system of Japan is compatible with that of Korea, which is traceable to another foreign national standard.In this paper, the result of the comparison test between two countries is described. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

A Study on Insulation Level Decrease of 22 kV Overhead Distribution Line in Isolated Neutral System

For insulation design of 22 kV overhead distribution lines, major guidelines have been specified: (1) Have enough insulation ability against the line’s internal abnormal voltage, while arresters are used against external abnormal voltage such a lightning surge. (2) Decrease the line insulation level by using specific arresters capable of regulating the switching surge, resulting in an overall BIL decrease. The first specification is commonly adopted because the arrester’s absorption energy against the switching surge is not yet identified. The revised JEC testing voltage standard specified further lowered the insulation level (LIWV 100 kV), but its target was only for the 22 kV overhead distribution lines in a resistance grounded neutral system. Recently, focus is placed on studying for protecting the lines from direct lightning strikes, thus a variety of lightning protection equipment is widely applied on the lines. Consequently, guideline (2) above is also taken into account. In short, 22 kV overhead distribution lines will achieve both decreasing insulation level and improving lightning protection ability by installing many arresters for LIWV 100 kV in an isolated neutral system. Given these circumstances, to make this idea feasible, the authors studied the absorption energy of the proposed arresters against the internal abnormal voltage of the 22 kV overhead distribution lines in an isolated neutral system. The results revealed that the arresters are well applicable to the 22 kV overhead distribution lines.

雷による配電線フラッシオーバ発生率算定手法の開発

Recent lightning protection design has been considered against not only induced overvoltages due to nearby lightning hits, but also overvoltages due to lightning direct hits on power distribution lines.Electric power companies are both expanding conventional protection methods such as overhead grounding wire and surge arresters, and developing new protection equipments with a Zinc-Oxide surge divider.In order to get effective protection method, it is important to study the relation between protection method and lightning outage ratio of a power distribution system.From the above point of view, authors developed the program which can calculate lightning outage ratio due to both lightning direct hits and indirect lightning hits. Moreover this program can consider interval of lightning protection equipment, grounding resistance, flashover voltage of the insulator, and characteristics of surge arresters at will. In this paper, detail of the developed program and comparison of calculated outage ratio according to lightning protection methods are described.