IEEE 80-2000

$100.75

IEEE Guide for Safety in AC Substation Grounding

Published By	Publication Date	Number of Pages
IEEE	2000

Guaranteed Safe Checkout

Category: IEEE

If you have any questions, feel free to reach out to our online customer service team by clicking on the bottom right corner. We’re here to assist you 24/7.
Email:[email protected]

Description

Revision Standard – Superseded. Outdoor ac substations, either conventional or gas-insulated, are covered in this guide. Distribution, transmission, and generating plant substations are also included. With proper caution,the methods described herein are also applicable to indoor portions of such substations, or to sub-stations that are wholly indoors. No attempt is made to cover the grounding problems peculiar to dc substations. A quantitative analysis of the effects of lightning surges is also beyond the scope of this guide.

PDF Catalog

PDF Pages	PDF Title
1	Title page
3	Introduction Participants
5	CONTENTS
9	1. Overview 1.1 Scope 1.2 Purpose
10	1.3 Relation to other standards 2. References
11	3. Definitions
16	4. Safety in grounding 4.1 Basic problem 4.2 Conditions of danger
19	5. Range of tolerable current 5.1 Effect of frequency 5.2 Effect of magnitude and duration
20	5.3 Importance of high-speed fault clearing
21	6. Tolerable body current limit 6.1 Duration formula 6.2 Alternative assumptions
22	6.3 Comparison of Dalziel’s equations and Biegelmeier’s curve
23	6.4 Note on reclosing
24	7. Accidental ground circuit 7.1 Resistance of the human body 7.2 Current paths through the body
25	7.3 Accidental circuit equivalents
28	7.4 Effect of a thin layer of surface material
31	8. Criteria of tolerable voltage 8.1 Definitions
34	8.2 Typical shock situations
35	8.3 Step and touch voltage criteria
36	8.4 Typical shock situations for gas-insulated substations
37	8.5 Effect of sustained ground currents 9. Principal design considerations 9.1 Definitions
38	9.2 General concept
39	9.3 Primary and auxiliary ground electrodes 9.4 Basic aspects of grid design 9.5 Design in difficult conditions
40	9.6 Connections to grid
41	10. Special considerations for GIS 10.1 Definitions
42	10.2 GIS characteristics 10.3 Enclosures and circulating currents
43	10.4 Grounding of enclosures 10.5 Cooperation between GIS manufacturer and user
44	10.6 Other special aspects of GIS grounding
45	10.7 Notes on grounding of GIS foundations 10.8 Touch voltage criteria for GIS
46	10.9 Recommendations
47	11. Selection of conductors and connections 11.1 Basic requirements
48	11.2 Choice of material for conductors and related corrosion problems 11.2.1 Copper 11.2.2 Copper-clad steel 11.2.3 Aluminum 11.2.4 Steel 11.2.5 Other considerations
49	11.3 Conductor sizing factors 11.3.1 Symmetrical currents
53	11.3.2 Asymmetrical currents
56	11.3.3 Additional conductor sizing factors
57	11.4 Selection of connections 12. Soil characteristics 12.1 Soil as a grounding medium 12.2 Effect of voltage gradient
58	12.3 Effect of current magnitude 12.4 Effect of moisture, temperature, and chemical content
59	12.5 Use of surface material layer 13. Soil structure and selection of soil model 13.1 Investigation of soil structure
60	13.2 Classification of soils and range of resistivity 13.3 Resistivity measurements
63	13.4 Interpretation of soil resistivity measurements
64	13.4.1 Uniform soil assumption
65	13.4.2 Nonuniform soil assumptions
72	14. Evaluation of ground resistance 14.1 Usual requirements 14.2 Simplified calculations
73	14.3 Schwarz’s equations
76	14.4 Note on ground resistance of primary electrodes 14.5 Soil treatment to lower resistivity 14.6 Concrete-encased electrodes
80	15. Determination of maximum grid current 15.1 Definitions
81	15.2 Procedure
82	15.3 Types of ground faults
84	15.4 Effect of substation ground resistance 15.5 Effect of fault resistance 15.6 Effect of overhead ground wires and neutral conductors
85	15.7 Effect of direct buried pipes and cables 15.8 Worst fault type and location
86	15.9 Computation of current division
91	15.10 Effect of asymmetry
93	15.11 Effect of future changes
94	16. Design of grounding system 16.1 Design criteria
95	16.2 Critical parameters 16.2.1 Maximum grid current (IG) 16.2.2 Fault duration (tf) and shock duration (ts) 16.2.3 Soil resistivity (r) 16.2.4 Resistivity of surface layer (rs)
96	16.2.5 Grid geometry 16.3 Index of design parameters 16.4 Design procedure
99	16.5 Calculation of maximum step and mesh voltages 16.5.1 Mesh voltage (Em)
102	16.5.2 Step voltage (Es)
103	16.6 Refinement of preliminary design 16.7 Application of equations for Em and Es 16.8 Use of computer analysis in grid design
104	17. Special areas of concern 17.1 Service areas 17.2 Switch shaft and operating handle grounding
107	17.3 Grounding of substation fence
115	17.4 Results of voltage profiles for fence grounding
116	17.5 Control cable sheath grounding 17.6 GIS bus extensions 17.7 Surge arrester grounding 17.8 Separate grounds
117	17.9 Transferred potentials 17.9.1 Communication circuits 17.9.2 Rails
118	17.9.3 Low-voltage neutral wires 17.9.4 Portable equipment and tools supplied from substation 17.9.5 Piping 17.9.6 Auxiliary buildings
119	17.9.7 Fences
120	18. Construction of a grounding system 18.1 Ground grid construction—trench method 18.2 Ground grid construction—conductor plowing method
121	18.3 Installation of connections, pigtails, and ground rods 18.4 Construction sequence consideration for ground grid installation 18.5 Safety considerations during subsequent excavations 19. Field measurements of a constructed grounding system 19.1 Measurements of grounding system impedance
122	19.1.1 Two-point method 19.1.2 Three-point method 19.1.3 Ratio method 19.1.4 Staged-fault tests
123	19.1.5 Fall-of-potential method
124	19.2 Field survey of potential contours and touch and step voltages
125	19.3 Assessment of field measurements for safe design 19.4 Ground grid integrity test
126	19.5 Periodic checks of installed grounding system 20. Physical scale models
127	Annex A—Bibliography
137	Annex B—Sample calculations
153	Annex C—Graphical and approximate analysis of current division
172	Annex D—Simplified step and mesh equations
175	Annex E—Equivalent uniform soil model for nonuniform soils
178	Annex F—Parametric analysis of grounding systems
193	Annex G—Grounding methods for high-voltage stations with grounded neutrals