Evaluation Of Lightning Performance Research Articles

Development of GIS-based Ground Flash Density and its Statistical Analysis for Lightning Performance Evaluation of Transmission Lines in Peninsular Malaysia

Malaysia is one of the world's highest lightning regions, making it an ideal location for studying lightning activities, as they cause many power outages on overhead transmission lines. This study presents ground flash density (GFD) mapping and statistical analysis of lightning flash data in Peninsular Malaysia, which will be used to evaluate the lightning performance of transmission lines. Using Geographical Information System (GIS) software, the GFD map and lightning flash data for statistical analysis were extracted. MATLAB was then used to perform statistical analysis and obtain the probability of peak lightning current using the generalized extreme value (GEV) distribution. This study analyzed six years of lightning flash data from 2012 to 2017 recorded by the Lightning Location System (LLS) and used the Peninsular Malaysia base map from the Department of Survey and Mapping Malaysia (JUPEM). Results show that the GFD mapping approach effectively classifies GFD distribution and identifies areas with high lightning activity. 81% of 4,536,380 lightning flashes were negative polarity, with a higher mean peak current magnitude than positive ones. More lightning activity was observed during the Southwest Monsoon (June-September) and the first Inter-Monsoon season (April-May). Pahang had the most lightning flashes due to its large land area. The GFD map overlaid on the transmission line demonstrated how lightning performance on the transmission line can be assessed. These findings are useful for utility and protection engineers to improve the performance of transmission lines.

A Study of Lightning Performance to Multi-grounded System of KEPCO MV and LV Distribution Network

This paper presents the indirect lightning performance evaluation of Korea Electric Power Company (KEPCO) medium voltage (MV) and low voltage (LV) lines. The main topic of this paper is to analyze an effect of the grounding systems on the indirect lightning performance of MV and LV distribution lines. To this end, we define the models of the MV and LV distribution systems for the analysis of distribution line surge overvoltage due to lightning. With reference to the data typically adopted by KEPCO, the research describes and motivates the use of the most suitable models of distribution lines, transformers, and surge arresters (SAs) to be implemented in EMTP like simulation environments. The sensitivity of the lightning performance of the distribution lines to different configuration of MV and LV grounding systems, distance between SAs, as well as presence of overhead ground wires is also analyzed. Regarding overvoltage, both the temporary overvoltage and the surge overvoltage are considered. The presence of SAs at the MV terminals of distribution transformers is also considered.

Lightning Performance Evaluation of Transmission Line Based on Data-Driven Lightning Identification, Tracking, and Analysis

Lightning performance evaluation is aimed at classifying transmission lines into different risk levels of thunderstorm-induced trip-out. Its applications range from better lightning protection guidance, arrester installation design, transmission line retrofits, and line corridor design. Previous studies fail to consider the real-time lightning intensity, which is an essential factor of lightning trip-out that must not be ignored. This article proposes a novel lightning performance evaluation model based on the idea that the tower, which has a record of lightning trip-out with weaker real-time lightning intensity, is more susceptible to trip out, which means low lightning performance. In order to quantify the lightning intensity, this article puts forward a new definition of lightning intensity which includes three kinds of real-time characteristics, that is the location, the current of lightning strike, and the number of times the lightning movement track crosses the transmission line. More specifically, with the rapid development of lightning location system, a novel Lightning Identification, Tracking, and Analysis algorithm is proposed to search lightning movement track based on a database of 17 million lightning records. When lightning trip-out happens, the lightning performance level is graded according to the real-time lightning intensity. By comparing the similarity of static characteristics, the lightning performance level is extended to the tower, which has no record of lightning trip-out. By comparison with the traditional model, the proposed model is closer to the actual situation and can significantly improve the accuracy of lightning performance evaluation, which is improved by 66.7%.

Lightning Performance Evaluation of Italian 150 kV Sub-Transmission Lines

A significant majority of overhead transmission lines’ (OHLs) outages is due to backflashovers caused by direct lightning strikes: the realistic assessment of the lightning performance is thus an important task. The paper presents the analysis of the lightning performance of an existing 150 kV Italian OHL, namely, its backflashover rate (BFOR), carried out by means of an ATP-EMTP-based Monte Carlo procedure. Among other features, the procedure makes use of a simplified pi-circuit for line towers’ grounding system, allowing a very accurate reproduction of transient behaviours at a very low computational cost. Tower grounding design modifications, aimed at improving the OHL lightning performance, are also proposed and discussed.

Investigation on Shielding Failure of a Novel 400-k$\text{V}$ Double-Circuit Composite Tower

In this paper, the lightning shielding performance of a newly designed 400-k $\text{V}$ double-circuit composite tower is investigated. Based on a revised electrogeometric model (EGM) method, traditional shielding failure regions located at both sides of a traditional tower are no longer a big issue for the fully composite tower, due to its unusual $^{\prime }Y^{\prime }$ configuration. Instead, a new unprotected region exists in the tower center. The maximum lightning current that can lead to shielding failure and the shielding failure rate of the new tower are calculated. To verify results from the revised EGM method, a scale model test is conducted. Spatial shielding failure probability around the tower is calculated based on the ratio of discharge paths recorded in the test. Moreover, based on test results, the maximum shielding failure lightning currents are obtained. Analysis and results derived from the revised EGM method and scale model test have a small deviation, verifying the feasibility of these two methods in the lightning performance evaluation of the fully composite tower. Both methods confirm that the unusual negative shielding angle of $-\text{60}^{\circ }$ in the newly composite tower provides good lightning shielding performance. The feasibility of the novel composite tower is verified from the lightning protection point of view.

Wide-Band Modeling of Tower-Footing Grounding Systems for the Evaluation of Lightning Performance of Transmission Lines

This paper presents the evaluation of lightning performance of transmission lines considering the wide-band modeling of their associated tower-footing grounding systems. To this aim, first, the grounding system admittance matrix over the frequency range of interest is obtained by making use of the method of moments solution to Maxwell's equations. In the next stage, the matrix pencil method is used to infer the pole-residue identification of the obtained admittance matrix. Finally, the obtained pole-residue model is incorporated into the EMTP-RV in the form of a state-space block. The back-flashover analysis is done for a typical 132-kV transmission line, while the tower-footing grounding system is modeled in three different ways namely: 1) static-model, 2) wide-band model assuming constant electrical parameters for the soil, and 3) wide-band model assuming frequency-dependent electrical parameters for the soil. From the simulations, it is found that the inclusion of the wide-band model of the tower-footing grounding system can markedly affect the total probability of back-flashover in transmission lines. This effect is more pronounced when the frequency dependence of soil electrical parameters is taken into account. It is shown that considering the wide-band modeling of tower-footing grounding system can affect (either decrease or increase) the total back-flashover probability of transmission lines.

Application of artificial neural network methods for the lightning performance evaluation of Hellenic high voltage transmission lines

Feed-forward (FF) artificial neural networks (ANN) and radial basis function (RBF) ANN methods were addressed for evaluating the lightning performance of high voltage transmission lines. Several structures, learning algorithms and transfer functions were tested in order to produce a model with the best generalizing ability. Actual input and output data, collected from operating Hellenic high voltage transmission lines, as well as simulated output data were used in the training, validation and testing process. The aims of the paper are to describe in detail and compare the proposed FF and RBF ANN models, to state their advantages and disadvantages and to present results obtained by their application on operating Hellenic transmission lines of 150 kV and 400 kV. The ANN results are also compared with results obtained using conventional methods and real records of outage rate showing a quite satisfactory agreement. The proposed ANN methods can be used by electric power utilities as useful tools for the design of electric power systems, alternative to the conventional analytical methods.

Long term experience on lightning acquisition in Italy and Austria and data application to the improvement of lightning performance

Lightning location systems (LLS) have been in operation in Italy and Austria for about 10 years. The two networks have been running a collaboration sharing sensors data since the beginning. The importance of this collaboration is shown, analyzing the behavior of the two networks as standing alone or as cooperating. In particular a detailed analysis is run on a set of data, evaluating the importance of the other network sensors in the calculation of lightning and in the efficiency and accuracy of the final results. The application of LLS data to improve the lightning performance evaluation of transmission and distribution lines is analyzed. Lightning density at ground is a key factor for performance evaluation of transmission lines. More accurate and detailed maps than those standardized may be derived from LLS, indicating that standardized values (average values for an area) are not sufficiently accurate to describe the situation of a given territory. The use of LLS data to correlate faults and lightning is discussed. For MV lines, one of the particular problems discussed is the necessary accuracy in lightning location.

An expert system for high-voltage substations lightning performance estimation

A computer-based expert system approach to the detailed lightning performance evaluation of high-voltage overhead lines and substations is described. All parameters causing the computation result uncertainty are systematized and analyzed. The importance of the optimal equivalent circuit design is emphasized. For a 400 kV substation layout the sensitivity study of the parameters of the equivalent circuit is performed and an optimal circuit is evaluated. The lightning and the computing parameters are studied and the default values for practical application are suggested. Some of the software possibilities using a multilevel menu system are presented. A statistical approach to the substation lightning performance estimation based on the discharge point moving along the span of the connected overhead line in front of the analyzed substation entrance is described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>