SINGLE BUS BAR ARRANGEMENT

This is the simplest switching scheme in which each circuit is provided with one circuit breaker. This arrangement offers little security against bus bar faults and no switching flexibility resulting into quite extensive outages of bus bar and frequent maintenance of bus bar isolator(s). The entire SubStation is lost in case of a fault on the bus bar or on any bus bar isolator and also in case of maintenance of the bus bar. Another disadvantage of this switching scheme is that in case of maintenance of circuit breaker, the associated feeder has also to be shutdown

Exothermic welding installation guide

Here is a guide for exothermic  welding system

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Shock indicator for new materials

Protect-A-Pak is a single use shock indicator that can be attached to the item being shipped or inside of shipping boxes via a self-adhesive backing. Protect-A-Pak is composed of a cylindrical plastic casing containing two springs, each of which is fitted between two steel balls. These springs are designed to withstand a specific rated g-force. If the acceleration exceeds the rated force, the two balls detach from the axis affected and fall into the plastic casing. As the springs are fitted at a 90 degree angle, each Protect-A-Pak can monitor two axes. A label on the outside of the packaging shows the shipper that an impact indicator is being used.

High voltage Transmission line bending due to a sand storm in Egypt

 A sand storm caused a totally bending  in a high voltage  transmission line in  Egypt .

Cable reels specifications (part 2)

• When lifting cable reels by crane, a steel shaft of proper length and diameter shall be placed through the reel drum spindle. The steel shaft shall be threaded at both ends and provided with circular plates and retaining nuts to prevent the reel from falling in case of accidental tilt during the lifting process
• When rolling a cable reel from one location to another, care shall be taken to remove any objects on the surface area that might contact the cable surface. The marked rolling direction must be followed to prevent the cable layers from becoming loose
• The cable storage site shall be an elevated flat surface and must not be reached by flood or sea water
• Reels shall be stored on a solid support or hard and regular surface that will not allow the flanges to sink into the earth.
• Storage areas shall be free of construction equipment, flying or falling objects, chemical or petroleum spill or sprays, open fires or other heat sources and far from heavy vibration areas.
• The conductor or ground wire in reel shall be protected by wood lagging to prevent damage. The conductor reels are set or stored on ground blocking. It is advisable to store the different types of conductors in separate locations. Blocking shall be used to prevent movement or rolling of reels. When the conductor or ground wire is not protected by wood lagging, in no case, shall the blocking touch the conductors or ground wire.

Source SEC standard

SEE previous article 

cable reels specifications (part 1)

·         Cable reels shall be stored and maintained in a proper manner. Cable reels shall be shipped with adequate physical protection to ensure that they can be stored in an outdoor environment for the period of time between arrival and installation

·         All shipping reels for LPOF, EHV & HV cables shall be made of steel. Reels for MV cables Shall be made of steel or wood. Steel strapped wooden lagging is required in all cases. The LPOF cable reels will include a shipping/storage oil pressurization system for the testing and maintaining of proper oil pressure on the stored cable.

·         LPOF cables, when prepared for shipment shall be subjected to expulsion test to check the entrapped gas as per AEIC CS4. Figure 02-06 shows the expulsion test panel

·         When the LPOF cables are completed and ready for shipment, samples of oil shall be taken from each length of cable as per AEIC CS4 to determine the dielectric strength of oil samples.

·         The selection and use of the proper equipment and tools used in cable reel handling is essential. A thorough knowledge of the capabilities of equipment, cable reels weight and physical dimensions are required prior to moving or loading the cable reels

·         For XLPE cables in reels, the inner end and the outer end shall be sealed with heat shrinkable end cap after attaching a pulling eye to the conductor. This sealing method will prevent ingress of moisture into the cable.

·         Care on reel deterioration should be taken if cable are to be stored for extended period. Wooden reels shall be stored on concrete base or on raised wooden stringers placed under the reel flanges.

·         Cable reels shall be stored in an upright position only. Laying cable reelson their flat sides are not allowed.

To be continued

Source : SEC standards