Frequency and Time Response of Power Plant Grounding System Exposed to Lightning Strike

<span lang="EN-US">Ground grid system is important for preventing the hazardous effects of overvoltage in high voltage substations due to fault current perhaps from lightning strike or device malfunction. Therefore, this study aimed to investigate the effects of overvoltage on square, rectangular and L-shaped ground grids with ground rods being distributed in mesh-pattern by using alternate transients program/electromagnetic transients program (ATP/EMTP) program. The models were simulated in the cases that 25 kA-fault current being injected into the center or one of the corners of ground grids. The results showed that the highest level of overvoltage (6.3349 kV) was detected at the corner of rectangular ground grid when the fault current was injected into its corner. However, the lowest level of overvoltage was found when the fault current was injected into the center of square ground grid. The results from this study indicated that ATP/EMTP program was useful for preliminary investigation of overvoltage on ground grids of different shapes. The obtained knowledge could be beneficial for further designing of ground grid systems of high voltage substations to receive the minimal damages due to fault current.</span>

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of overvoltage on square, rectangular and L-shaped ground grids of high voltage substations by ATP/EMTP

Luewattana

Rattanasena

2021

“…According to [1], lightning discharges are characterized by short duration of high electric voltage and current pulses. Also, lightning event is arbitrary, unpredictable and can strike anywhere on earth with current value that could exceed 40kA, induce temperature up to 50,000 degrees Fahrenheit, and move at speed closing to 33% speed of light [1], [2]. Lightning is the transient passage of electrical current between a cloud and either the surface of the earth, another cloud, or an object in or near a cloud.…”

Section: Introductionmentioning

confidence: 99%

“…Lightning strikes, especially C-G, has continued to be subject of studies in different locations and conditions as depicted in [2], [5], [7]- [9]; especially as it impacts protective grounding designs and locations; empirical intensities, physical processes in different geographical locations have been the foci. These mostly location specific foci and approaches are particularly central for sub-saharan Africa studies, where dependence on foreign models and technologies are predominant.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Lightning Strike Events, and it’s Correlational with Power Outages in South-West Coast, Nigeria

Melodi¹,

Oyeleye²

2017

This paper aimed to model lightning strike events and evaluate its correlation with power outages in a Nigerian power distribution system. A specified coastal distribution network of southwest Nigeria was selected as a case study. Zone-specific records of cloud-to-ground lightning strikes for 84 months were obtained from the Nigerian Meteorological Agency (NiMet); records of power outage frequencies and durations for 36 months were obtained at the substations of the selected distribution network. Using numerical statistical analysis techniques, lightning activity in the system area were characterized in relative frequency terms, and correlation statistics were evaluated and analyzed for power outages and lightning events on the 11kV, 33kV, and 132kV voltage levels. An analysis of the results shows that the modelled lightning strike events patterns are closely related but the expected frequencies vary from one zone to another; and there is correlation between lightning strike and power outages in the distribution networks, which is strong and positive at the 33 kV and 132 kV circuits. In essence, the results provided salient information, useful for power systems lightning protection review, management and planning in the area. Keyword:Lightning

“…Recently, Current Distribution in Earth and Grounding System (CDEGS) program has been used for illustrating the three-dimentional (3D) plots ofpower plant grounding system that was exposed to the lightning current. The results suggested that the spatial distributions of the scalarpotentials and the electric fields werelargely affected [7]. In addition, the severity of lightning strikeon transmission line tower andnearby gas pipeline was explored by using Power System Computer Aided Design (PSCAD) and CDEGS programs, and CDEGS could give more precise results of the effect of soil structure on induced voltage [8].…”

Section: Introductionmentioning

confidence: 99%

Overvoltage Effects on Ground Grid Systems of Single and Two Neighboring High Voltage Substations

Luewattana¹,

Pruksanubal²

2016

The power networks with reliable transmission and distribution systems require high voltage substations with effective ground grid systems. Therefore, this study aimed to analyze the effects of overvoltage on ground grid systems within high voltage substations in two cases, including a single substation and the two neighboring substations, by using ATP/EMTP and ANSYS softwares. The simulations were performed to show both graphs and 3D results when the fault current flowed into the ground grids of substations at various positions. In case of the single high voltage substation, the overvoltage was highest when the fault current was injected at the corner of ground grid. However, in case of two neighboring high voltage substations, the levels of overvoltage were similar between that caused by injecting the fault current at the center and at the corner of ground grid. The simulation showed that overvoltage which occurring at the ground grid of high voltage substation A could permeate to the ground grid of nearby high voltage substation B, which nevertheless depending on the how the fault current was injected at different spots. The data from these simulations and analysis can be useful for future designs of ground grid systems with high reliability.