Q257 : Definition of Computation Methods for Step Voltage
Question What are the differences between the various options available for the computation of step voltages?
Answer When the program computes the step voltage at a given point, it needs to compute the potential difference between that point and a nearby point located at a distance specified in the "Stride" field (typically 1 meter). The problem is that the potential at that nearby point may be unavailable. For instance, the computation profiles can be specified in such a way that the spacing between adjacent computation points is larger than the stride. When that happens, the program will first determine the location of suitable test points close to the desired point, and compute the worst step voltage between the desired point and all of those points. The value that is reported (and plotted) depends on the computation method as follows:
- Worst spherical: the worst step voltage obtained above is rescaled to obtain the corresponding value at a spacing equal to the stride. - Human worst: the worst step voltage obtained above is rescaled to obtain the corresponding value at a spacing of 1 meter. In this case, the "stride" really indicates a search radius around the desired point; the resulting sphere is scanned to locate suitable test points
This last option can be used to extend the search region without making the stride larger than 1 meter.
The Average Spherical method is generally less useful, and will not be discussed further.