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In grounding system design, there are many parameters that affect touch voltage, step voltage, and grid resistance such as depth of grid, mesh size, number of rod, length of rod, size of buried conductor, etc. This research simulated effect of mesh size, number of rod, and length of rod, where 3 design models were created. Model 1 using 4 rods with length per rod 3m and mesh size 20 × 20m, model 2...
In order to improve the corrosion maintenance efficiency of grounding grid metal, the corrosion state of underground grounding grid in an 110kV substation was tested and evaluated by the electrical impedance tomography (EIT) technology. Results indicated that the impedance increase ratio of grounding grid branch was in a reasonable range below the warning value, proving the whole ground grid metal...
The paper deals with the protective relaying of MV rings recently introduced by e-distribuzione, the largest Italian Distribution System Operator (DSO). The paper refers to an existing MV distribution system which includes a loop line. Attention is focused on Cross-Country Faults (CCFs), i.e. two Line-to-Ground Faults simultaneously occurring in two different phases at different locations. A large...
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...
The demand of electricity transmission toward regions for society, industrial and other needs are increasing hence, making electricity transmission and distribution increased as well. The increase in electricity transmission and distribution requires addition of Substation construction. Substation constructions are crucial for economic growth in Indonesia. This research aims to design two models of...
External grounding grid is an effective measure to reduce grounding resistance of grounding grid. In order to meet the requirements of the grounding resistance in the most economical way, it is important to determine the distance and the area of the external grounding grid. Generally speaking, when the area is larger, the grounding resistance is smaller. When the distance of the external grounding...
Proper operation of any power system depends on reliable performance of the substations. In any substation, a well-designed grounding system plays vital role. Since the grounding system should preserve safe and effective operation of control and protective devices. This work is to investigate the optimum design of the grounding system of a typical high voltage substation of 500/220 kV Egypt. The design...
When an overhead electric power distribution circuit conductor breaks—for example, when a car strikes a pole or a splice or clamp fails—the energized conductor falls to ground. The resulting high-impedance ground fault may be difficult or impossible to detect by relays located in the substation. In any case, no ground fault protection relay can operate until well after the time the fault has occurred—after...
This paper presents a safe and economic grounding system design for the substation of Ain El-Melh located in M'Sila city (Algeria) using genetic algorithm optimization (GAO). The main objective is to minimize the cost function of the considered grounding system in accordance with the security restrictions required by the ANSI/IEEE Std. 80-2000. A new mathematical model has been proposed for the cost...
Grounding grid is an important equipment to guarantee the safety and reliable of power system. It should be diagnosed regularly to prevent from corrosion, which is significant to ensure the safety of people and equipment. It has a significant value to do some research on the algorithm of grounding grid diagnosis. Contact voltage, step voltage and ground resistance are the most important characters...
This paper describes hands-on solid modeling experience of the safe optimal ground grid design (less copper) for a large Extra High Voltage (EHV) substation. The optimized ground grid meets the IEEE-80 standards for safety without compromising on step or touch potential thresholds. The ground grid has been designed in CDEGS using fault current flow concepts, and multiple injection points simulate...
This paper presents touch voltage reduction technique for uniform and two-layer soil by applying grid compression ratio. The design of ground grid is discussed pertinent to its maximum touch and step voltage produced for a given GPR. The parameters are analyzed to ensure that they conform to the IEEE 80-2000. It is found that, for a given GPR, the maximum touch and step voltages of the rectangle grid,...
A grounding practice which has been widely adopted as a personal protective measure for carrying out de-energized line works is causing many fatal accidents. The conclusion was arrived after analyzing a fatal accident. This method of protective grounding is still practiced by many distribution companies without realizing the imminent danger involved. The paper explains how this particular practice...
Industrial substation grounding studies usually assume a simple isolated substation, follow the routine IEEE 80 design and analysis procedures using the software tools bundled with the power systems analysis suite of choice, and carry on with the rest of the project. However, there can be complications to substation grounding designs. This paper discusses two case studies where a ground fault in one...
The following work investigates the risk of electrocution from earth potential rise at transmission substations and nearby third party locations as a result of a power system earth fault. Current earthing standards use a deterministic approach where the risk assessment considers a set of worst-case conditions. However, it is recognised that most of the parameters involved in calculating the earth...
A connection between a phase conductor and the ground in MV networks is called earth fault. The fault current in this case does not depend on the point of the fault, but only on the total capacity (size) of a network. Distribution system operator (DSO) sometimes needs to operate the large network which means operating of the network with big capacitive current (in Czech Republic more than 800A). This...
Unequally spaced method of grounding grid can economize metal material on the premise of ensuring the safety of equipment and personnel. A new optimization formula of grounding grid buried in uniform soil is presented in this paper. An analysis of grid conductor spacing of unequally spaced grounding grid was done. Serial number was given to each conductor as a specific numbering. A conversion formula...
It is an effective method for detecting and evaluation substation's grounding grids with break and corrosion to measure magnetic induction intensity. But it will be faced with complicated EMI problem to measure effectively magnetic induction intensities in substation. So power frequency harassment and transient EMI caused by switching operations are measured practically in a few substations. These...
The paper deals with the clarification of basic terms related to the calculation of the earth potential rise (EPR), transferred potential and earth resistance of the earthing grid. In case of earth fault occurring in a substation, significant fraction of the fault current is flowing in the passive conductors (cable sheath, earth wire) of the lines feeding to the fault. These passive conductors are...
This article presents a summary of the standard design procedures successfully used by several Brazilian utilities to control electromagnetic interferences in power plants, substations and telecommunication installations. Those users stated in articles and conferences that the reported procedures controlled very well the interference problems in their facilities. The article shows that usual cable...
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