CYME CYMGRD v6 3 R3golkes: A Software for Substation Grounding Design and Analysis
CYME CYMGRD v6 3 R3golkes is a software program that helps engineers optimize the design of new and existing substation grounding grids, of any shape, by using finite element analysis and danger point evaluation facilities. The software conforms to IEEE standards and allows for the rapid analysis of various design alternatives to choose an economical solution for any particular installation.
The software is part of the CYME Power Engineering software suite, which includes applications for transmission, distribution and industrial power network analysis, cable ampacity calculations and protective device coordination. The software is developed by CYME International, a company that provides power engineering solutions and services to customers worldwide.
CYME CYMGRD v6 3 R3golkes can be downloaded from the official website of CYME International[^1^] or from other online sources[^3^]. The software requires a license key to activate and run. Users can request a trial version of the software by filling out a form on the website[^2^]. The software also provides customer technical support and user group forums for assistance and feedback.The grounding network bonds all the metallic parts of the substation equipment and structures, creating a low impedance path for the fault currents to flow to the earth. The connection to the earth is the interface between the electrical system and the earth, which provides a reference potential for the grounding network and dissipates the fault currents into the soil.
The design of a substation grounding system involves several steps, such as:
Collecting data on the substation layout, equipment ratings, fault levels, soil resistivity, and environmental conditions
Calculating the grid current, ground resistance, and ground potential rise (GPR) of the grounding system under fault conditions
Designing the grid geometry, conductor size, and rod depth to meet the safety criteria for step and touch voltages, as well as equipment withstand limits
Verifying the design using computer software or field measurements
Applying mitigation measures if necessary to reduce the step and touch voltages or GPR, such as adding ground rods, increasing conductor size, installing crushed rock or asphalt layers, or using equipotential bonding
The design of a substation grounding system requires a balance between safety, reliability, and cost. A well-designed grounding system can protect personnel and equipment from electric shock hazards, improve the operation of protective relays, and increase the availability of the electrical system.Step and touch voltages are the voltages that a person may be exposed to when standing near a grounded object during a fault. Step voltage is the voltage between the feet of a person, while touch voltage is the voltage between the hand of a person and the feet. Both voltages are caused by the potential gradient on the earth surface due to the fault current flowing through the soil.
Step and touch voltages are dangerous because they can cause electric shock to a person. The magnitude of the shock current depends on the body resistance and the voltage difference between the body parts. The shock current can cause involuntary muscle contractions, cardiac arrest, or even death. The severity of the shock also depends on the duration of the fault, the frequency of the current, and the path of the current through the body.
The maximum tolerable step and touch voltages are determined by various standards and regulations, such as IEEE 80â 2000, IEEE 81â 1983, and IEEE 837â 2002. These standards provide formulas and tables to calculate the safe values of step and touch voltages based on factors such as body weight, soil resistivity, fault duration, and surface material. The design of a substation grounding system should ensure that the step and touch voltages do not exceed these values. 061ffe29dd