Substation grounding

Substation grounding software

Analytical capabilities

• Finite element analysis of the ground grid conductors and rods
• Computation of the station ground resistance (Rg) and the Ground Potential Rise (GPR)
• Touch and surface potential analysis, inside and outside the grid perimeter, with color display in 2D or 3D representation
• Step voltage analysis
• Uniform or two-layer soil model from field measurements or user-defined values
• Computation of reduction factor (Cs)
• Library of the most common types of surface layer materials
• Library of typical station soil resistivity values
• Safety assessment calculations for maximum  permissible touch and step voltages as per IEEE 80 2000
• Current Split Factor (SF) estimated from substation configuration data as per IEEE 80 2000
• Computation of the Decrement Factor (DF) from bus X/R ratio and shock duration data as per IEEE 80 2000
• DC component of asymmetrical fault current taken into account in the computations
• Electrode analysis for the optimal sizing of conductors and rods based on the most common type of electrode material as per IEEE 80 2000 and IEEE 837 2002
• Supports symmetrical or asymmetrical grids of any shape
• Arbitrarily located ground rods
• Ability to model return electrodes and distinct electrodes
• Ability to model concrete encased rods
• Computation of maximum allowable single phase to ground fault current for a specified grid

CYMGRD/AUTOCAD interface module

Eaton's CYMGRD/AUTOCAD Interface module allows the user to alternate between the AutoCAD and the CYMGRD environments.

This utility is not a substitute for AutoCAD. In fact, AutoCAD remains a firm software requirement, because it is AutoCAD that will produce the necessary *.DXF or *.DWG file(s) that contain the pictorial description of the substation grid layout realized with the CYMGRD software.

Simulation results management

The charts functionality allows:

• Graphical comparison of deduced soil model with field measurements, for model acceptance
• Color-coding of the surface potential gradients based on user-defined thresholds for touch or surface potentials. Any area of the grid can be selected with the mouse for detailed calculations and danger point evaluation
• Equipotential contours for surface potentials in either 2-D or 3-D plots, with facilities to examine the graphs from any desired viewing angle
• Graphics of touch and step voltage variation along any straight line, with comparison to the safe values computed by the safety assessment module
• Graphic indications on the 2-D grid layout of the area being analyzed for touch and step voltages, for easy identification of hazardous locations