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To balance the potential distribution on the surface of a substation, an equal spacing arrangement of the grounding grid conductors is not an economical solution. The implementable solution is an unequal placement of its constituent elements. The design methodologies of such a configuration are complex and require computer-assisted numerical analysis. This paper proposes and validates a very simple method, based on an arithmetic progression, of arranging the conductors of the grounding grid that guarantees the reduction of touch and step voltages, ensures the efficiency of the material used and has no limitations on its applicability for atypical substation surfaces (too large or too small), respectively for few or many parallel conductors. To certify the method, the proposed algorithm is analyzed, through the CYMGRD Substation Grounding Program, and compared to the technologies currently applied, for the substation grounding grid presented as an example in the IEEE Guide for Safety in AC Substation Grounding 80™- 2013 standard.

The analysis of adjacent grounding systems under lightning currents which is responsible for many safety problems to human beings and damages to devices is very important. In this study, the behaviours of such grounding grids under lightning conditions which are not well documented in the literature are analysed using the multi-conductor transmission line method in a two-layer soil model. To achieve this goal, the expressions related to the study of a single grounding grid extracted from the recent study of the authors are developed to be appropriate to the analysis of adjacent grounding systems under lightning currents. Also, through the representation of the connectivity matrix, the analysis of the adjacent grounding grids with any size and degree of complexity is facilitated. Furthermore, the behaviours of the adjacent grounding grids under different lightning and soil characteristics are examined and some conclusions are derived.

This article investigates the impacts of electric potential (EP) and electromagnetic fields (EMF) on human health, especially for those living or working near a distribution system, as a co...

It has been determined that the discharge of lightning current to ground through grounding grid results in high potential at the grounding grid and other nearby grounding grids, which is very destructive. In the present paper, based on artificially triggered lightning technology, the characteristics of the ground potential rise (GPR), the transient effect at the active grid under the transient impulse of lightning current was analyzed. The impulse grounding resistance is found to decrease for large input currents. On the other hand, for small input currents, it usually increases. In addition, the characteristics of the transfer potential of the passive grid which is located 40 m from the active grid were analyzed. It was shown that the peak value of the transfer potential at the passive grid was approximately 5.1% of the peak value of the ground potential at the active grid during the return stroke. The achievements made in this study may contribute toward the optimization of the simulation model.

Transient electromagnetic (TEM) method is a reliable means of non-destructive testing for fault diagnosis of grounding grid in substation. In view of the small transmitter loop of the TEM system and many measuring points and survey lines of grounding grid detection in substation. This study presents a fast solution to TEM apparent resistivity imaging for grounding grid detection using artificial neural networks. The input -output mapping relation of neural network is established based on TEM response characteristics of the grounding grid. The built network could map the recorded TEM data of grounding grid detection and quickly obtain the resistivity image. The proposed method offers accuracy and fast computation for the resistivity imaging of grounding grid. Feasibility and technical attractiveness of the proposed method in fast imaging of apparent resistivity is investigated with the measurement of grounding grids in the actual substations. It can be used in real time so that the recorded TEM data in substation can be calculated without re-training, which avoids time-consuming inversion computation. The rapid processing of massive data and submitting the detection results of the grounding grid to customers rapidly and in real time, which is expectation for a modern power industry.

Nondestructive testing of substation grounding grids is an issue that has increasing importance. The traditional EMI method transforms the condition of the undergrounding conductors to the surficial induced electric signal in the sensing coil. However, The EMI signals excited by multiple coexisted faults combining with other unknown noises surrounding the substation often cause the failure of detection. Therefore, the observed EMI signals rather complex and cannot be used directly. To address this problem, the separation of individual signatures from the mixture is posed as an SCBSS problem. To extract the induced signal, an EEMD-based EMI method is proposed. The desired signal is then reconstructed to visualize the structure of the grounding grids by a virtual instrument that consists of DAQ and digital signal processing modules. The numerical simulation and practical experiments are employed. The results show the proposed method can be used to effectively detect the topological structure of grounding grid in real substations' electromagnetic environment.

The grounding grid is an important part of ensuring the safety of power plants and substations, and its performance is directly related to the safety of people, equipment and power grids. After the grounding grid is running, due to the concealment of the project, it lacks sufficient technical means to evaluate it after it is put into operation, which has caused many difficulties for equipment operation, personnel safety and grounding grid maintenance. In order to solve the above problems, this paper uses CDEGS software to simplify the modeling of the grounding grid of a substation, and evaluates the performance of the grounding grid by analyzing the soil resistance layered model, touch voltage, step voltage and other parameters of the grounding grid, and give an optimization plan.

This paper gives the different grounding mat design modifications and the impact on the design parameters of these modifications. Different modifications in different cases like case 1: grounding mat design without earth electrodes, case 2: grounding mat design with the electrodes at the corner of mat, case 3: grounding mat design with compression ratio without earth electrode, and case 4: grounding mat design with compression ratio and earth electrodes have been applied with the application of ETAP 16.0.0 version software. The primary framework of the grounding mat solidly depends upon, \( R_{g} \), \( V_{\text{touch}} \), \( V_{\text{step}} \), and ground potential rise (GPR). These quantities are of great concern for safety of any grounding system. Here, our main concern is to minimize the design quantities by inserting electrodes and by changing the compression ratio to meet the standard safety regulations annunciated in various guidelines and standards. Here, in this paper, homogeneous soil model is considered for designing the grounding mat.

Lightning transient characteristic of the grounding grid is fundamental for optimum performance of lightning protection of a substation. In order to design an appropriate grounding system for such substation, it is important to study its transient characteristics because the high impulse current is significantly different compared to power frequency current. In this paper, substation grounding grid model was developed using CDEGS software to analyze the grid transient performance in terms of ground potential rise (GPR), touch voltage and step voltage when the grounding system is struck by a lightning impulse current. Several parameters, such as lightning current amplitude, feed point and the number of sub-grids, were altered to study their relationship with the transient performance. The maximum transient GPR, touch voltage, and step voltage increase as the lightning current amplitude increase. The maximum transient GPR and step voltage are the highest at the corner of the grounding grid while the maximum touch voltage is the highest at the centre of the grounding grid. In addition, the maximum transient GPR and step voltage decrease when the number of sub-grid increases. In contrast, the touch voltage slightly increases as the number of sub-grid increases. The maximum transient GPR, and step voltage are the highest at the 2-layer and the lowest at the uniform soil or single-layer soil.

Optimizing the grounding grid configuration is an effective approach to improve the performance of grounding grid. On the other hand, configuration of grounding grid is necessary for some defect diagnosis method to detect the faults existing in grounding conductors. This paper employs the transient electromagnetic (TEM) method to draw the configuration of a substation grounding grid. The surface magnetic field is recorded by receiver coils above the grounding grid. Based on the regular distribution characteristics of a recorded magnetic field, the grounding conductor is accurately located from the curve of magnetic intensity. The complete process of configuration detection of the grounding grid is described in detail. After fast inversion calculation of the recorded magnetic field, the equivalent resistivity is obtained. The configuration of the grounding grid will be clearly and accurately shown in the contour map and three-dimensional (3-D) surface map of equivalent resistivity. Model study is performed, and a field test is also conducted. The results are in good agreement to demonstrate the effectiveness of TEM method for configuration detection of the substation grounding grid.

This paper deals with the computation of ground resistance, surface voltage, touch voltage and step voltage, to mesh with horizontal wires arranged in different angles. The computer program implemented used in the mathematical modeling is based on the method proposed by Heppe, which allows obtaining the grounding parameters for homogeneous soil and soil stratified in two layers. The results obtained with the proposed method will be compared with other methods in literature. Also will be presented the results of a grounding grid using wires at various angles.

Substation design that refers to IEEE Standard 80–2000 can be carried out through manual calculation. Considering that there are lot of data involved used and also repeated calculations, it will be very difficult and requires high accuracy. Therefore, a computer-based computing system is needed to solve this problem. This paper discusses an application modelling of LabViewgraphical user interface to provide convenience in designing the substation grounding grid. Some options have been developed such as grounding grid resistance calculation method, conductor diameters determination, grounding grid selection with ground rod and without ground rod and weight body. The effect of any changes in design can be known directly and compared with limit of the touch voltage and the step voltage allowed. For validation, the model used data from Std. 80–2000 and compared with some design model already existed. As a result of this application, grounding grid design process will be easy, more accurate, and faster.

The ground potential will rise abnormally when impulse current injects into grounding grid if a converter substation is struck by lightning or there exist short-circuit faults. Transient ground potential rise (TGPR) could couple to the cable core wire through conductive and near-field coupling ways and it will invade the secondary system eventually. Taking those two coupling ways into consideration, this paper builds a simulation model describing the technisim on how TGPR couples to the secondary cables in an UHVDC converter substation and searches for the best grounding way for suppressing disturbance voltage in secondary cables’ cores caused by TGPR. Through simulation and test, for a single cable harness with armor double-ended grounded, we propose that cable’s shielding sheath should be grounded only in protecting cabin. For a four-segment cable, we find the best grounding way is that for the harness segment between protecting cabin and terminal box, we should guarantee armor double-ended in both sides while shielding sheath be grounded only in protecting cabin, for the segment between terminal box and operating cabinet, we should guarantee armor double-ended in both ends while shielding sheath be grounded only in terminal box, what’s more, the armor and sheath among operating cabinets should be grounded only in phase B’s cabinet.

This study presents the comparative analysis of three grounding grid configurations to find the optimum grid design in terms of safety parameters. Square grid, rectangular grid and L-shape grid, buried in two-layer soil model are taken in this study. Same grounding area is considered to design three different configurations of grounding grid. Effect of different grid designs, shapes and dimensions on grounding system performance is noticed. Equal and unequal spaced grounding grids for each shape are designed and it is found that unequally spaced rectangular grid gives better results than other considered designs. Study shows that rectangular grid has minimum value of grounding system resistance, grounding potential rise and mesh voltage in comparison of square and L-shape grid. ANSI/IEEE standard 80–2000 are used to designing the grids and all safety constraints are followed as mentioned in the slandered. Good agreements are found with unequal spaced rectangular grounding grid in comparison of square and L-shape grid. Two-layer soil structure is considered in the analysis. Vertical rods are placed at the periphery of the grid.

The grounding device plays performs the role of releasing a lightning current and a fault current in the power system, and the corrosion of the conductor will cause damage to the grounding body, which threatens the safe operation of the power system. The grounding grid corrosion detection technology and equipment guarantee the safe operation of the power system. This paper discusses the research status of grounding corrosion and topological detection in detail and introduces the basic principles, research difficulties and existing problems of the methods such as the electric network method, electromagnetic field method, electrochemical method, ultrasonic detection method and electromagnetic imaging method. The methods of electromagnetic imaging and time difference positioning proposed in recent years have been also discussed in detail. The paper points out that the application of grounding grid corrosion detection distance engineering still faces great challenges and that multi-disciplinary, multi-information fusion, new sensing technology, big data platforms and intelligent computing will be the trends to follow in research on grounding grid fault, corrosion detection and life prediction.

The corrosion condition of the grounding grid of the converter station is very important to ensure the safety and stability of the power system. From the perspective of the leakage current of the converter station equipment, the circuit model of the leakage current in the DC field of the converter station is proposed; According to the leakage current characteristics, the DC field of the converter station is divided into the high-voltage side and the neutral-pole side area; According to the actual situation of the converter station, a measurement and analysis platform suitable for the leakage current of the converter station equipment is built; Through field test, the leakage current of each area equipment is measured and analyzed, and the distribution characteristics of equipment leakage current in different areas are summarized; According to the measurement data, the areas and equipment types that should be focused on corrosion problems are proposed.

The lightning impulse behavior of substation grounding grids plays a very important role in lightning protection of substations and the grounding design of the grounding grid around the down leads has great influence on it. This paper analyzed the lightning impulse behavior of substation grounding grids with different grounding designs around the down lead, including the connection points, local refinement and layout of vertical grounding poles around down leads. Results showed that special designs around down leads including multi-point connection, local refinement and vertical grounding poles could improve the transient behavior of substation grounding grid. Meanwhile only increasing the number of vertical grounding poles cannot improve the transient behavior significantly.

Today with increase in use of microgrid, appropriate grounding design is needed for it. In this paper it is done by considering different grounding shapes for the MG. For this purpose, paper evaluates the performances of triangular, rectangular, square, L shape and T shape grounding design considering uniform and two layer soil structure. Influence of diverse designs on safety parameters such as touch voltage and step voltage are examined. Investigation is done with the help of ETAP based finite element method and for its authentification, results obtained by it are substantiated with analytical results obtained through IEEE standard 80-2013. As per the results obtained, triangular shape performs better. Also, this paper reveals the touch and step potential profiles for different shapes.

Developing cracks in the soil by means of explosions in the holes, as is called the explosion grounding electrode in this study, is a very effective way to reduce the grounding resistance in the area with high resistivity soil. In this study, the influence of the grounding grid scale and the arrangement of the grounding electrode on reducing the grounding resistance of three-dimensional grounding grid with explosion grounding electrode are studied. There is a strong shielding effect between the explosion grounding electrodes. When the distance between the explosion grounding poles is short, the effectiveness of reducing the grounding resistance by using the long explosion grounding electrode is obviously restrained. The distance between the explosion grounding electrodes should be more than half the length of the electrodes.

The mathematical models proposed in the literature are used to determine the grounding resistance value for electrical installations. These models are mathematical expressions that change according to grounding type and the mechanical properties of the grounding system elements. Besides, the inclusion of nonlinear terms is another important issue in the modeling studies. For the modeling of nonlinear systems and the analysis of the faults that may occur, the finite element analysis (FEA) approach provides realistic results. In the present study, the simulation of a grid fault that may occur in the grounding system of a sample wind turbine (WT) is modeled by 2D electrostatic solver in FEA software. The simulation results prove that the findings are similar to the realistic faults in the grounding system. © 2019 Published by peer-reviewed open access scientific journal.

In the intelligent substation, the shell of the secondary equipment is connected to the ground grid locally. When the short circuit fault current is injected into the grounding grid to cause the ground potential rise, the potential difference between the two points of the grounding grid will affect the normal operation of the secondary equipment. In this paper, aiming at the grounding grid of a 220kV substation, the grounding impedance, ground potential rise and ground potential difference between galvanized flat steel and copper grounding grid are calculated by using CDEGS software. The results show that the copper ground grid has a significant effect on reducing the potential difference of the ground grid.

The condition of thesubstationgrounding grid is vital for the safety of the people. Inadequate grounding may cause failures in majorsubstation's equipment, as well as in control, metering and telecommunication equipment. Therefore, it is necessary to clearly identify damaged elements on grounding grid. This paper presents an approach to test the integrity of the grounding grid in a general framework of IEEE Std. 81-2012. More precisely, in order to locate damaged grounding riser(s) and/or grounding grid conductor(s), this paper is focused on novel unambiguous criteria for post-processing of raw-data collected from the measurements. In order to avoid the effect of power frequency interference on the measurement, we use DC test current of 100A. The field test is described and discussed in details. The outcome of field test clearly shows the validity and feasibility of the proposed approach.

The role of the grounding system in the safety of the power system and protection of personnel is obvious during an unexpected short circuit or lightning discharge at the substation. The aim of this work is to analyze the effects of several parameters: lightning impulse front time, soil resistivity and types of grid materials on the grounding system of the Substation. The ground potential rise (GPR), touch voltage and step voltage of a 50 m x 60 m grounding grid buried at a depth of 0.5 m were computed using CDEGS when injected by impulse with different front times. Results show that the shorter the front time of lightning impulse waveform, the higher the value of GPR, touch voltage and step voltage. Meanwhile, when the value of soil resistivity is increased, the value of GPR, touch voltage and step voltage is also increased. Lastly, different types of grid conductor materials give different values of GPR, touch voltage and step voltage. However, it can be said that the differences are too small to be of any significance.

The metro stray current will flow through the neutral point of the transformer from the grounding grid in the soil, causing the transformer DC bias phenomenon. In order to effectively evaluate the influence of metro stray currents on the transformers, the traction current in metro, the “rail-current drainage net-earth” grounding network structure, and the DC bias current loop were equivalent, so a resistance model for the transformer DC bias caused by stray current was built. Then the dynamic equation of transformer neutral point current with time and metro train position was established, and the neutral point current can be solved by LU decomposition. The software CDEGS was used to build train and transformer simulation model. By comparative analyzing the transformer neutral point current between the simulation results and the calculation results of the proposed modeling method, the model error was small, which can be effectively applied to the evaluation of transformers affected by metro stray current.

This paper presents the design of 220kV substation grounding grid with difference resistivity soil according to horizontal and vertical two layer soil model is structure using the MALT program of CDEGS Software. The target of this paper is to minimize the touch and step voltages when the resistivity soil is high, in 220kV urban substation pending a direct lightning stroke. Also, it is shown that for a sensor located on the ground, close to 220kV substation, the magnetic field component vertical to the structure can also experience a considerable attenuation, perhaps due to the effect of the induced currents in the substation. The results are confirming by numerical simulations, obtained using NEC-4 and IEEE Guide for Safety in AC Substation Grounding. The step by step procedure for designing 220kV substation grounding grid has been presented for which design parameters were obtained by CDEGS Software.

In this paper, development of a data processing software for grounding grid fault diagnosis of power substation based on the state response analysis (SRA) with impulse current is introduced. The SRA method with impulse current for grounding grid of power substation is described in detail firstly. Then the main function of the developed software used to analyze and display the measured current and voltage waveshapes is presented, including data loading, data display, parameter calculation, database management and correlation analysis to achieve fault diagnosis for grounding grid of power substation. At last, two examples of tests to the grounding grids with filed measured data are shown. All of that provides an effective technical support for grounding grid fault diagnosis based on the SRA.

Secondary devices are important components of a substation. The overvoltage due to the short circuit fault may interfere and do harm to the secondary devices. Based on the short circuit test of a ±500 kV converter station, the overvoltage of secondary cables in the substation was measured. The ground potential distribution of the grounding grid was calculated. Results show that the ground potential difference between two ends of secondary cables may cause overvoltage between core and shield and they are in the same order of magnitude.

In unequally spaced grounding grid the buried horizontal interconnected conductors are placed at unequal space in such a manner that denser and closely spaced grid conductors placed near periphery of the grid than center of the earth grid. So grounding grid design in unequally spaced manner may be more safe than equally spaced in which there are greater space between horizontal conductors at the center of grid and distance between adjacent horizontal conductors are gradually decreased from center to the periphery of grid. This paper describes the method to design safe and economic unequally spaced grounding grid from equally spaced grounding grid for 220/132 kV substation without using ground rods in uniform soil to overcome the drawback of equally spaced grounding grid. By designing grounding grid in unequally spaced manner may save grounding grid materials also.

The behavior of grounding systems excited by high-current show great differs from that at low-frequency and low-current. Simulation of high-current draining to earth require accurate modeling of tower grounding system. The current model cannot meet this requirement. This paper proposed an accurate time-varying nonlinearly model of grounding systems established by ATP-EMTP, aiming at simulating the impulse characteristic of grounding systems. The results indicated that the strong agreement between the model and experimental values. At the end of this paper come to the calculation that the active length of the grounding bodies ray is 40 m in the grounding grid. And increasing the ray length infinitely is not conducive to reducing the impulse grounding resistance. The results above can be used for optimizing the grounding grid and selecting the length of grounding bodies ray.

Faults in the grounding grid are a hidden danger to the safety of power systems and cause significant economic loss every year. This paper presents a new means to locate faults in grounding grids using the transient electromagnetic imaging method. The method compares the distribution characteristics of the equivalent resistivity of the underground covered by grids for the no-fault case and those with break points. We describe why and how the proposed method can be used for the break-point diagnosis of grounding grids. Simulation was performed using the Ansoft finite-element method package, and a field experiment was conducted to verify the effectiveness of the proposed method. This study provides a practical means for break-point diagnosis with no requirement of power shut down or soil excavation. Moreover, the proposed method does not require the design drawings of grounding grids.

In this paper, we present a numerical model based on the boundary element method that allows to analyze the grounding systems (GSs) of aboveground and underground substations under different locations and considerations. The proposed formulation allows to consider most of the specific properties and conditions of this kind of substations, i.e., complex geometry, different material properties, and different grounding grid configurations, and to study phenomena like transferred potentials by earthing electrodes. Finally, GSs of real substations have been analyzed as application examples.

Since more elements are involved in the construction projects, the decision making process of Resource-constrained Project Scheduling Problems (RCPSP) cannot be determined by a manager, but multiple level decision makers. This study focuses on the RCPSP in a practical grounding grid system project in Jin’ An Qiao hydropower station, which consider the hierarchical organization structure and hybrid uncertainty environment simultaneously. In this practical RCPSP, the construction contractor is the Upper Level Decision Maker (ULDM), while the outsourcing partner is the Lower Level Decision Maker (LLDM). Considering the operations difficulties and practical decision making process in the RCPSP, a bi-level multi-objective RCPSP model with bi-random coefficients is developed. To deal with the bi-random variables in the model, the Dependent-Chance Programming (DCP) method is introduced and the equivalent crisp model is derived. Subsequently, motivated by the particular nature of model, Bi-level Global-local-neighbor Particle Swarm Optimization Algorithm (BGLN-PSO) is designed to obtain the optimal schedule for grounding grid system project. A practical application is presented to verify the efficiency of proposed bi-level multi-objective RCPSP model and algorithm.

The grounding system in a solar farm has unique characteristics due to its extended footprint and varying type of grounding components. The changing physical properties of the soil within the perimeter of a solar farm result in the nonuniform resistivity of the top soil layers. Measurements of the as-built grounding grid could indicate higher grounding resistance than that predicted by design. Once this difference is detected, it is the duty of the designer to modify the existing grounding grid such that the touch potential is below the limits specified by the applicable codes. This paper presents the analysis of the touch potentials in solar farms and also provides some recommendations to reduce these potentials when the grounding resistance is higher than that predicted by the design. An actual grounding grid design and field measurements are used in an example to illustrate the concepts introduced in this paper.

The configuration of grounding grids which are used to earth electrical substations could be equally or unequally spaced. Unequally spaced grids were introduced to improve the requirements of the grids such as grounding grid resistance (Rg), ground potential rise (GPR), maximum touch voltage (Et) and maximum step voltage (Es) values. Also, unequal spacing can reduce the cost of the grids and enhance the level of safety for people and equipments. In this paper two different approaches were used to determine the best possible configuration of grounding grid. These approaches based on sequential multiplicative and sequential power techniques.

The corrosion of grounding grids can result in a grounding accident of a power system, and much attentions has been concentrated on the method used to detect a corrosion fault in a grounding grid, in which the methods of voltage measurement and magnetic field measurement are usually used. In this paper, a cycle voltage measurement method and L-curve regularization method are proposed to locate the faults in grounding grids. The L-curve method was used to select the appropriate regularization parameter, which can effectively balance the error and stability of the solution to the inverse problem. The uncertainty of the solution due to the ill-posed problem in the inverse problem has been well-solved. Experiments were conducted in a laboratory with two network types. In addition, a field experiment was carried out in a 110-kV substation. Both of the results showed that the method can effectively locate a branch fault with a single branch and multiple branches in the grounding grids.

In order to study the influence of vertical grounding electrode on impulse grounding resistance of substation ground network, the grounding model was built in COMSOL, and the impulse grounding resistances of substation grounding grid in different distribution, length and quantity of vertical grounding electrode were simulated and calculated. The results show that the closer the vertical ground to the lightning current injection point is, the smaller the impact grounding resistance is. The impulse grounding resistance, that has a minimum value, decreases first and then increases with the increase of the vertical grounding electrode length. When the additional vertical grounding electrodes are placed in accordance with the evacuation outside and internal density manner within a certain region ranging from the lightning current injection point, the impact grounding resistance has the best reduction effect.

When substations suffer from lightning, the potential difference occurs within the grounding grid, which will generate induced voltage between the core, shield and the armor of the two-end grounded cables and significantly affect the secondary system in substation. This paper analyses the potential difference within large grounding grid and its influence on the secondary cables through the field test. The induced voltage in cable was measured and analyzed. The usage of drain wires was studied.

Grounding system plays very important role in AC substation station for person and equipment safety. Proper design of grounding system is achievable by following IEEE Std-80 on safety in AC substation grounding but novice professionals find it not easy to use. The advantage of this paper presents evaluation of grounding system for AC substation by case studies presentation thus easing the understanding of IEEE Std-80 and its usage. This was carried out by using homegrown Sub-ground software with capability to identify the safety status of a grounding system design procedures. The grounding system is evaluated with six different cases. Different parameter is changed in each case to observe the result of the grounding system. The result shows that there are several important parameters in designing a grounding system. The parameters are grounding grid size, number of parallel rod, level of fault current, crush rock layer, cross sectional area of ground rod and level of soil resistivity. The tolerable and calculated step and touch voltage as well as the mesh voltage of the grounding system are presented in manner to tutor novice professionals on AC grounding system design. Last but not least the software developed in the laboratory useful for novice professionals training for AC substation grounding system.

As the large grounding grid occupies large area, the potential difference on the grounding grid is obvious, and the proportion of inductive components in the grounding impedance is larger. Then the design and the operation of the grounding grid are different from the small grounding grid. The paper studies the characteristics of resistive component and inductive component in the grounding impedance of the large grounding grid. The factors affecting the grounding impedance and the features of the large grounding grid are discussed. The results can provide a technical reference for design, operation and maintenance of the large grounding grid.

The grounding system requires for maintaining safety of operators and apparatus and ensuring reliable working of power network. A grounding of substation connects electrical apparatus and the metallic structures to the common ground. Grounding system of substation should be such that it should limit the potential gradients with in and around substation during normal and fault condition. Ground Fault creates potential rise within and around the substation which increases the step and touch potential. These potentials should be less than the permissible human body limit. For examination grounding grid of substation needs to calculate parameters related to earth and grounding for safe operation. In this paper parameters of existing design of grounding grid of substation are calculated with IEEE standard 80-2013 and some techniques are discussed for increasing grounding system safety. ETAP (Electrical power system analysis) software is used for analysis.

This paper presents the design of grounding grid system for substations. In last past years the design engineers follows steps of grounding grid design as per IEEE standard 80–2013, which is complicated process. This digital application is mainly concerned with development of Standalone software with using Visual Studio, named by “Grounding Grid Designer”, which calculated accurate grounding system as per guidelines given by IEEE standard 80–2013. After applying this computer aid application the complexity as well as time will reduces. This paper mainly conduct three mostly applicable grounding grid design:-Square Shape, Rectangular Shape, and L-shape. After developed software, the results obtained by standalone software is compared by sample calculation of square grid with ground rods design which is given into the IEEE 80–2000 standard in Annex B.

The grounding grid plays an important role in the safe and reliable running of substation, The study on detection and fault diagnosis of grounding grid will provide an effective means for its state evaluation. This paper proposes a multiple parameter imaging method for grounding grid by pulsed electromagnetic inverse, that aims at accurate positioning and quantitative evaluation of corrosion and breakpoint for power system grounding grid, and the new method intends to realize the image reconstruction of electrical conductivity, permittivity and structure for grounding grid. Using the characteristics of electromagnetic wave propagating in different medium surface, the new method establishes the mathematical-physical model and analyzes the electromagnetic field propagation characteristics between grounding grid and the surrounding medium.

In this paper, we proposed a training model to predict the corrosion rate for substation grounding grid based on the Similarity and Support Vector Regression (SSVR). In the proposed model, the effect of grounding grid corrosion rate was acted as a feature vector and processed by a dimensionless treatment. Then, the similarity between the feature vector of training terminal and index vector of actual site would be calculated. In the prediction of corrosion rate, the traditional Linear Average Method (LAM) to describe the nonlinear contribution has some fault defects. Therefore, we proposed the training model named SSVR. From the experimental results, the proposed SSVR can obtain better predicting performance than the traditional LAM.

The corrosion characteristics of grounding grid in different kinds of resistance-reducing agent were analyzed. The corrosion characteristic of carbon steel in different resistance-reducing agent was presented. Comprehensive evaluation on construction technology was made. Moreover, reference for the protection of the grounding grid and the safe operation were provided.

A nonparametric cluster classification prediction model was established aiming at small sample and parametric modeling of grounding grid corrosion rate. First of all, a grounding grid corrosion rate level classification strategy was used to reduced the complexity of the prediction model; secondly, a selfhelp method (Bootstrap) was utilized to produce Bootstrap subsets, avoiding small sample problem; finally, multiple weak classifiers were generated for all bootstrap subsets with nonparametric – KNN classification and the Adaboost method and were clustered into a strong classifier. The experimental result shows that, compared with the KNN classification method, corrosion rate levels resulting from the nonparametric cluster algorithm can be matched with the actual results better, and this model is suitable for the grounding grid corrosion rate prediction.