Download CYMGRD Users Guide PDF

TitleCYMGRD Users Guide
Tags Electricity Electric Current Electrical Resistivity And Conductivity
File Size1.7 MB
Total Pages141
Table of Contents
                            GETTING STARTED
	General introduction
	Software and hardware requirements
	Installing CYMGRD
	CYMGRD modules
	First-time user
	Interactive data entry
	How to use CYMGRD to design a new grounding grid
	Dividing the grid into elements
	How to use CYMGRD to reinforce and verify existing grounding grids
	Creating and opening Projects and Studies
	The Windows layout of CYMGRD
SOIL RESISTIVITY AND SAFETY ASSESSMENT
	Soil resistivity measurements and soil models
	Soil resistivity: Methodology and algorithm
	How to perform a soil analysis
	How to specify the soil model type
	How to perform Safety Analysis
	Transferring the results of Safety Analysis for danger point evaluation
	Importing Projects from the previous version
	Importing Projects from the previous version – An
THE GRID ANALYSIS MODULE
	General introduction
	Electrode types and terminology
	Electrode Sizing
		LG fault parameters
		Electrode Material
		Electrode Sizing report
	Grounding system structure and location
	Entering the Grid data
		Asymmetrically-arranged grid Conductors
		Symmetrically-arranged ground Rods
		Asymmetrically-arranged ground Rods
		Arc Conductors
	Modifying and inspecting the station Geometry data
	Importing/Exporting Grid data and Station layouts
	Overlapping conductor elements
	Grid analysis and reports
	Visualize the station layout in 3-Dimensions.
	The station layout and the ‘Installation’ view.
	A note on modeling Grounding Structures
	Soil data from earlier versions of the application
THE PLOTTING MODULE
	General introduction
	How to generate ‘Touch’ and ‘Surface’ potential C
	Touch and Surface potential contours
	Contour color coding and Safety Analysis
	How to generate 3-D contour plots
	Contour graph reports
	Contour graph management
	How to perform ‘spot-check’ danger point evaluati
	How to generate Profile voltage plots
	Inspecting potential profile plots
	Comparing contour plots from two different studies
EXAMPLE STUDIES
	Example 1: Primary electrode only
	Methodology
	First step: Soil Analysis and interpretation of resistivity measurements
	Third step: Grounding installation data entry
	Fourth step: Danger point evaluation and surface analysis
	Example 2: Primary, Return and Distinct electrodes
	Grounding installation data and layout
Comparison with the IEEE80 Guide
	Comparison with the IEEE80 Guide
		CASE NAME: Example 1: Preliminary design stage.
		CASE NAME: Example 2: Improved design.
		CASE NAME: Example 3: Finalized design.
CADGRD - The CYMGRD - AutoCAD Interface module
	Program summary
	Drawing a station ground grid with AutoCAD
		General outline
		Drawing the Grid Layout using AutoCAD:
		Example
	Validation & Update of the AutoCAD drawing
		Validating the AutoCAD drawing
		Updating the AutoCAD drawing.
	Importing from AutoCAD to CYMGRD
	Exporting from CYMGRD to AutoCAD
	Working with AutoCAD
Appendix A – New Features in CYMGRD
Appendix B - Troubleshooting
                        
Document Text Contents
Page 1

USER'S GUIDE AND REFERENCE MANUAL











October 2006



CYMGRD 6.3 for Windows

Page 71

CYMGRD 6.3 for Windows

Chapter 5 – Example Studies 65

Chapter 5


EXAMPLE STUDIES

In this chapter, two step-by-step sample studies are detailed: A primary electrode only model,
below, and a Primary, Return and Distinct electrodes model, Section 5.6.

The descriptions of the two examples show how the most commonly used functions of the
application are actually utilized.

5.1 Example 1: Primary electrode only

In this example, the grounding grid is square and symmetrical (meshes of equal area). It is
76.2 meters long and 76.2 meters wide. All conductors are buried at a depth of 0.5 meters. Nine
conductors lie parallel to the X-axis and Nine parallel to the Y-axis. The diameter of all the
conductors is 19.1 millimeters. Finally, 25 grounding rods are connected to the grounding grid at
the perimeter. The rods are 10.9 meters long with diameter 2.858 centimeters (1-1/8 inches).
There are no auxiliary grounds in the vicinity and the fence of the station is to be disregarded, for
now.

The grounding installation is in parallel with a resistance of 25 ohms, simulating the presence
of overhead sky wire and counterpoise resistance. The total fault current is 4000 Amperes, but
since the equivalent impedance of the sky wires is not infinite (9999 ohms), not all of that current
will contribute to the station potential rise.

This example shows how to build the station from scratch with all resistivity measurements
taken along the same direction, using the Wenner technique, in order to determine the soil
characteristics.

In order to test the Soil Analysis module in CYMGRD, the following measurements were
obtained from one of IEEE sample. (IEEE 80-2000, page 168 & 169. Soil type 2)

Page 141

CYMGRD for Windows

Index 135





INDEX


Allowable LG fault current .......................... 131
Arc Conductors .............................................. 34
Asymmetrically-arranged grid Conductors .... 31
Asymmetrically-arranged ground Rods.......... 33
AutoCAD Interface module ........................... 91
Comparing contour plots ................................ 61
Comparison with the IEEE80 Guide .............. 83
Contour color coding...................................... 53
Contour graph reports..................................... 56
CYMGRD modules.......................................... 2
Default Parameters ....................................... 125
Dividing the grid into elements ........................ 4
Drawing a station ground grid with AutoCAD93
Drawing the Grid Layout using AutoCAD .... 94
Electrode Material .......................................... 25
Electrode Sizing ............................................. 24
Electrode Sizing report................................... 26
Electrode types and terminology .................... 23
Entering the Grid data .................................... 29
EXAMPLE STUDIES.................................... 65
Exporting from CYMGRD to AutoCAD ..... 121
First-time user................................................... 3
General introduction......................................... 1
generate Profile voltage plots ......................... 59
GETTING STARTED...................................... 1
Grid analysis and reports................................ 38
GRID ANALYSIS MODULE ....................... 23
Ground Electrode sizing by CYMGRD ....... 125
grounding grid .................................................. 4
Grounding installation data and layout........... 77
Grounding installation data entry ................... 70
Grounding system structure and location ....... 27
Importing from AutoCAD to CYMGRD ..... 119
Importing Projects .......................................... 19
Importing/Exporting Grid data and Station

layouts ........................................................ 37
Installing CYMGRD ........................................ 2

Interactive data entry ........................................3
LG fault parameters ........................................24
Maximum Permissible Shock Duration........130
Methodology and algorithm ...........................12
modeling Grounding Structures .....................45
Modifying and inspecting the station Geometry

data .............................................................36
Overlapping conductor elements ....................37
PLOTTING MODULE ..................................47
Primary electrode............................................65
Primary, Return and Distinct electrodes.........77
profile plots.....................................................61
Program summary...........................................91
reinforce and verify existing grounding grids ..5
Rod Encasement ...........................................129
Safety Analysis .........................................17, 53
Software and hardware requirements ...............1
soil analysis ....................................................14
Soil data ..........................................................46
soil model type ...............................................16
soil models......................................................11
SOIL RESISTIVITY AND SAFETY

ASSESSMENT...........................................11
Split-factor (Sf), Decrement- factor (Df) and

Definition for Remote-Contribution in [%]127
spot-check’ danger point evaluation...............58
station layout and the ‘Installation’ view........45
Symmetrically-arranged ground Rods............32
Touch’ and ‘Surface’ potential Contours .......47
Transferring the results...................................19
Troubleshooting............................................133
Updating the AutoCAD drawing..................117
Validating the AutoCAD drawing................113
Validation & Update.....................................113
Visualize the station layout in 3-Dimensions .41
Windows layout of CYMGRD.........................8
Working with AutoCAD ..............................122

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