Substation Safety – Are You Rock Solid?

Substation design typically calls for 2-6" of aggregate (crushed rock) as a top layer upon completion of construction. This layer serves several purposes, including …

Surface Material for Substation Ground Grid

I suggested the crushed rock should be the surface material to be used, my colleagues suggested should be the asphalt, as they are telling me that the crushed rock bottom is steel grating, and below the steel grating is an open space for transformer oil containment. Thanks. Regards, Bilegan Murphy's Law - If anything can go wrong..it will.

SPECIFICATION NO. 12 SUBSTATION GROUNDING …

The switchyard surface shall be dressed to a depth of 100 mm with crushed rock and extending 1.50 m beyond station fence line. For GIS substation, the switchyard surface shall be dressed to a depth of 150 mm around the building, and crushed rock extended 1.5 m beyond the fence. (If applicable) 2.1.4 Layings

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30" Fill with Crushed Rock (Typ.) Riser Entrance from Rack or Metal-Clad Sub. See working drawing for location. (See Note 3.) 4/0 Bare Copper Neutral Wire Slope conduits to proper depth to meet incoming conduits at substation fence. Full Encasement Length as Shown on Working Drawing 48" 2" 2" 6" 6" 6" 6" 1" Finger Holes for Lifting Every 4th ...

Non-Conductive Fence for 138kV Substation

Fiber glass fence could be an option. We used none conductive fence for a metropolitan utility in the North East coast. I will check the spec to see if we allow to share the info. In other project similar to the one described, we restored the area outside the property line beyond the fence with 24 inches of crushed rock.

Direct Buried Conduits – Substation Below …

Inside the substation, conduits route the cables from the yard equipment to the control house. To enable this, conduits can be either directly buried or placed in a cable trench. ... Crushed rock to top it off …

Substation Design

The Iowa State Senior Design team will submit a substation layout—including substation equipment, the control building, rigid bus, structures, and perimeter fence—based on the …

Application of Crushed Rock in Substations

Why Stones Are Used In Substation

Stone type: Crushed granite, limestone, or other hard, non-porous stones are preferred due to their high electrical resistivity and drainage properties. Stone size: Typically, a gradation of sizes ranging from 3/4 inch to 1 inch is recommended for optimal packing and drainage. Substation gravel size

Testing and application of crushed aggregate for use as a …

For the purposes of IEEE Std 80 and touch and step voltage analysis in substation grounding system design, the primary role of substation surface material is to increase series resistance to thereby limit current through the human body. Therefore, with a surface layer of high resistivity material installed higher touch voltages may be …

Design Guide for Rural Substations

bulletin 1724e-300 page 6 appendix a—typical substation drawing checklist.....73 appendix b—u.s. department of agriculture rural utilities

Power Grid Corporation of India

Power Grid Corporation of India

Testing and application of crushed aggregate for …

For the purposes of IEEE Std 80 and touch and step voltage analysis in substation grounding system design, the primary role of substation surface material is to increase series resistance to thereby …

Gravel Size Chart, Crushed Stone and Rock Sizes

Crushed Stone #10 (Stone dust or screenings): Usually 1/8″ Wide or Smaller. Crushed stone number 10 is the finest grade and is often referred to as dust or rock/gravel screenings. Resembling coarse sand, #10 is produced as a byproduct of the crushing process and has many uses in the construction and landscaping industries:

STANDARD SPECIFICATION PART 1

2.04 CRUSHED ROCK FOR BELOW GROUND INSTALLATIONS A. Gravel or crushed rock material shall contain less than 1% asbestos by weight or volume and conform to the Standard Specifications for Public Works Construction, Section 200-1.2 and shall meet the following gradation: Designated Rock Size 1-1/2-Inch 1-Inch 3/4-Inch 3/8-Inch Sieve …

(PDF) Guidelines to properly designed substation grounding

2.4 Design of a Substation Grounding System The substation ground grid design is based on the substation layout plan. The following points serve as guidelines …

Why Crushed Rock is Laid in Substations

There are in fact two main reasons why gravel is laid inside substations: 1. Improved safety during earth faults and lightning strikes; and 2. Improved fire suppression during oil fires. 1. Gravel improves safety during …

Design and Analysis of Substation Grounding Grid with …

V. USE OF CRUSHED ROCK LAYER ( s) A layer of crushed rock on surface helps in limiting the human body current by adding resistance to the equivalent body resistance. The values of s vary from 1000-5000 Ω -m. VI. RESISTANCE OF THE HUMAN BODY The human body can be represented by a non-inductive resistance (R B) for both …

Substation Grounding Design Challenges And Lessons …

crushed rock resistivity testing •california substation •3,000 ohm -m crushed rock was difficult to find. •compacted asphalt is 10,000 ohm -m (wet) •2" layer of compacted …

(PDF) Guidelines to properly designed substation grounding

Two –Layer soil model was utilized, average soil resistivity of 64.84 Ωˑm was determined 3. Total clearing time of a line to ground fault is 0.5 seconds. 4. Grid will be buried 18" (0.4572 m) 5. Crushed rock layer inside the substation is 4" (0.1016 m) 6. Ground rods will be 10' (3.05m) 7. Resistivity of the crushed rock layer is 3000 ...

Crushed Rock Spec Sheets | KRC Rock Landscape and …

KRC Rock Crushed Rock Specification Sheets. 700 North Twin Oaks Valley Road, San Marcos, CA 92069, USA ©2020 by KRC Rock Landscape & Building Supply

FLEXIBLE-PAVEMENT MATERIALS (INCLUDING …

stabilization including limerock, shell, shell-rock, cemented coquina shell, and recycled concrete aggregate (RCA). 911-2 Materials. 911-2.1 General: 911-2.1.1 Approval of Material: Approval of mineral aggregate sources shall be in accordance with 6-2.3. 911-2.1.2 Deleterious Substances: Materials shall not contain deleterious

Substation Grounding Tutorial

Eduardo has international experience in substation construction, O&M, and design in substations up to 500 kV. He has practiced engineering in the U.S., Canada …

OPTIMIZATION OF AC SUBSTATION GROUND GRID …

as washed crushed rock and would not be maintained in the same way as substation clean crushed rock. In most cases there is just pit run gravel, which has a much lower resistivity than washed crushed rock. This must be taken into consideration to ensure personnel in the station area have an added safeguard from shock. D. Ufer Grounds

Substation Grounding: Role of Crushed Rock

Ever wondered why crushed rock is spread over the surface of an electric substation? This article goes through the reasons behind this practice. When current is injected in to substation ground …

Electrical Substation Surface Material Resistivity …

Interior Corrosion Services can perform resistivity testing for crushed rock surface material supply for sub-station construction. A minimum sample size of 40-Litres is required for our testing purposes. Electrical resistivity …

substation stones

Thus, it is important that the resistivity of rock samples typical of the type being used in a given area be measured. So you see, the presence of crushed rocks are essentially for protecting the lives of the substation personnel and for soil moisture retention. Refer to IEEE 80-2000 for more detailed explainations. _____

Gravel in Switchyards

Generally the substation plan is prepared before the grid design . The earthing grid should cover as much ground area as possible . Soil resistivity can be determined using the four probe method . A thin surface layer of crushed rock helps in limiting the body current . A value of 3000 ohm-m is assumed for resistivity of crushed …

Offshore Substation General Requirements Functional …

ODS-GFS-00-001-R1 EirGrid Offshore Substation General Requirements Functional Specification Page 3 of 22 9.4.1 SCADA 15 9.4.2 PROTECTION COMMUNICATIONS 15 9.4.3 VOICE 16 9.4.4 DATA 16 9.5 TARIFF/REVENUE METERING 16 9.6 SECURITY 16 9.7 NAVIGATION AIDS 16 9.8 FIRE PROTECTION 16 9.9 EXPLOSION PROTECTION …