XGSLab New Feature - Seasonal Analysis For Grounding Systems
In regions where the frost depth meets or exceeds the depth of a grounding system, the grounding system’s performance may be dramatically reduced, possibly creating hazardous conditions. The latest XGSLab release 9.5 provides a powerful new tool to analyze grounding system performance that considers the seasonal variation in soil characteristics. In this webinar, given by David Lewis, an electrical engineer at EasyPower, we describe the effect that seasonal variation can have on a grounding system and we step you through the use of the Seasonal Analysis tool.
Answers to Q&A Following Live Webinar
| Question | Answer (David Lewis, PE at EasyPower) |
| What percentage of seasonal effect of soil on resistance and touch voltages, approximately? | Seasonal variations can more than double your grounding system impedance, but effects are dependent on your region and analysis specific. Seasonal Variation may increase your impedance, but also reduce the total fault current contributing to a ground potential rise, and increase your permissible limits. Again each site will have a different effect, but design/analysis processes can be developed on a regional basis. |
| What temperature condition is the default condition for the resistivity calculation in the software? | XGSLab has some default coefficient's for the temp to soil resistivity relationship (clay, Fairbanks soil, saturated soil, and granite). In the libraries, there is a 'soil properties' icon. There is not a default temperature in the software, but it would be populated based on review of historical temperature. You can check the history on weather.com, NOAA, or other similar resources. |
| Can you summarize the essential climate data required for creating a seasonal model? | The Seasonal Analysis tool requires user's input the mean annual air temperature, the yearly fluctuation of air temperature, and an approximate date in spring that the days temperature is equivalent to the mean annual air temperature. |
| Is XGSLab mainly a substation application? | XGSLab has several applications, including general grounding system analysis, cathodic protection, AC interference, lightning performance, and flexible short circuit software. Check out our website for more information https://www.easypower.com/products/xgslab-grounding? |
| Is it possible to design Gas Insulated Switchgears earthing with this software. | Yes, XGSLab can suppport various types of sites/facilities, including GIS stations. Just to note that have analysis process similar to typical grounding analysis, though, additional analysis may be required to evaluate metal to metal touch voltage with XGSLab. |
| 1) What is difference between finite element method & IEEE method? 2) What are the drawbacks of IEEE over finite element method? 3) Does IEEE have drawbacks such as the shape of the entire electrical substation being rectangle in shape? |
1) IEEE Std 80 provides a few hand calculation methods to evaluate a grounding system's impedance, and calculate touch and step voltages. These calculation methods have several limitations such as the geometry of a grounding system, soil layers/resistivity, and also uses some assumptions like equipotential plane. 2) This means IEEE calculations cannot be applied to many projects. 3) XGSLab uses the PEEC (partial Element Equivalent Circuit) method, which provides accurate calculation of complex system(s) geometry, soil modeling, energization, etc. Software solutions like XGSLab are inexpensive especially when compared to the cost under/over design of a grounding system, not to mention the hazards to human life that can occur. |
| Does XGSLAB support IEC compliance? | Yes, XGSLab supports the calculation of permissible voltage limits for IEC 60479. |
| Does XGS lab calculate spilt factor? | Yes, XGSLab provides split factor calculations in a simple format based on reference standards the user selects. The NETS module is capable of analyzing complex fault splits with multiple phases, sources, and infrastructure and the interface is typical of a short circuit software. |