IEEE Std 1246 pdf free download

IEEE Std 1246 pdf free download.Temporary Protective Grounding Systems Used in Substations.
3. Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE Standards
Dictionary: Glossary of Terms & Definitions should be consulted for terms not defined in this clause.5
bracket grounding: The location of temporary protective grounds (TPGs) on all sides of a worksite. The location of the TPGs can be immediately adjacent to or some distance from the worksite.
cluster ground assembly: A preassembled set of four cable or bar assemblies, with three phase connections and one ground connection, all terminating at a common (cluster) point.
continuit: A continuous, unbroken electrical circuit. For the purposes of temporary protective grounding. any device capable of transforming voltage or producing a significant voltage drop cannot be considered as maintaining continuity. Examples include transformers, fuses, reactors, resistors, circuit breakers, and line traps.
equipotcntial zone (equipotential grounding): A general term used to describe the application of temporary protective grounds to limit the potential across the worker’s body. It is often associated with worksite or single-point grounding but also includes other applications of temporary grounding.
ground potential rise (GPR): The maximum voltage that a station-grounding grid can attain relative to a distant grounding point assumed to be at the potential of remote earth.
multipoint grounding: The application of temporary protective grounds (TPGs) on either side of the worksite plus TPGs at the worksite. See also: bracket grounding: worksite (single-point) grounding.
phase-to-ground (parallel) grounding: The installation of temporary protective grounds from each phase to ground. The ground attachment point can be a common point for all three temporary protective ground (TPG) ground connections or can be a different point for one or more TPG ground connections, but a low- resistance connection between any separated TPG ground connection points is required.
worksite (single-point) grounding: The application of temporary protective grounds only in the immediate vicinity of an electrically continuous worksite. The location of the temporary protective grounds (TPGs) must be close enough to the worksite to prevent a hazardous difference in potential across a worker at the worksite.
4. Considerations for temporary protective grounding systems
4.1 General TPG
Temporary protective ground equipment is used when grounding a substation power bus and equipment to protect personnel from high voltages that can be induced or applied because of equipment failure or operating error. The TPGs can be properly sized and assembled to protect personnel from injury during a steady state or abnormal power system operation. This is accomplished by creating a short circuit (using the TPGs) to deenergize the circuit as soon as possible while minimizing the exposure voltage at the worker.
4.2 Permanent or mobile substation
TPG assemblies are applicable for both mobile and permanent substations.
4.3 Current magnitude and duration
The current magnitude and duration of the short-circuit current are critical factors in sizing TPGs. The protective ground is sized to conduct the maximum available short-circuit current at the short-circuit location without failure tbr the duration of the short circuit.IEEE Std 1246 pdf download.