ICEA P Short Circuit Performance of Metallic Shields and Sheaths on Insulated Cables. standard by Insulated Cable Engineers. ICEA P SHORT CIRCUIT PERFORMANCE. OF. METALLIC SHIELDS AND SHEATHS. ON. INSULATED CABLES. Approval by. AMERICAN. TEST METHOD FOR MEASUREMENT OF HOT CREEP OF POLYMERIC INSULATIONS. ICEA S ICEA S standard for power cables.
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Open wire lines have a high reactance. Join your peers on the Internet’s largest technical engineering professional community. Any input on how you calculate shield resistance would be appreciated. For three-phase circuits, use voltage to neutral and resistance and reactance of each conductor to neutral.
The formula also seems to imply that the shield resistance is independent p-45-4882 the diameter of the shield, which seems wrong to me. The percent voltage drop is the same between conductors as from conductor to ground and should not be multiplied by iceea.
The following equation can be utilized to find the reactance of icwa given configuration by using the concept of geometric mean radius. Shield losses due to circulating currents go down by approximately 2 percent, which brings energy costs down. Cable weight, pounds per ft Prysmian recommends that a recognized manufacturer supply the correct grip s on an individual p-45–482 basis, utilizing the formula shown above.
Multiple conductors with common covering a. To obtain symmetrical radial distribution of voltage stress within the dielectric, thereby minimizing the possibility of surface discharges by precluding excessive tangential and longitudinal stresses.
Using a mechanical clamp such as a constant tension spring or a hose clamp is usually adequate to secure the connection.
Formula 3 may be used to calculate -p45-482 effective cross-sectional area of the shield for new cable. Grounding of the Insulation Shield The insulation shield must be grounded at least at one end and preferably at two or more locations.
General Calculations Excerpt from PRYSMIAN`S WIRE AND CABLE
It covers spacing encountered for conduit wiring as well as for open wire circuits. Grips are not suitable for all vertical riser installation and the above is offered as a general guide only. The effective icez area of a shield or sheath needed to withstand a given short-circuit current for a given time.
To reduce the hazard of shock.
Insulated Cable Engineers Assoc., Publication No. PRevised – Google Books
For additional security, a mechanical device, such as a clamp, may be used to fasten the ends of the connection together.
Importance of Shielding Where there is no metallic covering or shield over the insulation, the electric field will be partly in the insulation and partly in whatever lies between the insulation and ground. XLPE jackets can allow reduced copper content and higher operating efficiencies.
Thank you 7anoter4 for your detailed response. Shielding which does not have adequate ground connection due to discontinuity of the shield or to improper termination may be more dangerous than non-shielded non-metallic cable and hazardous to life. It’s easy to join and it’s free. Voltage regulation is often the limiting factor ciea the choice of either conductor or type of insulation.
XLPE’s higher abrasion-resistance can also reduce potential cable damage during icsa. Metallic shield – should be nonmagnetic and may consist of tape, braid, concentric serving of wires, or a sheath.
XLPE MV Jackets Bring Sustainable Benefits
To confine the dielectric field within the cable. While the heat loss in the cable determines the maximum current it can safely carry without excessive deterioration, many circuits will be limited to currents lower than this in order to keep the voltage drop within permissible values. While resulting in slightly higher reactances than p-45-4882 cables in a non-magnetic duct, it is optimal relative to the alternative of a single cable in a magnetic duct.
The effective area of composite shields is the sum icsa the effective areas of the components. In common with other electrical equipment, the use of cable is not recommended on systems where the ratio of the zero to positive sequence reactance of the system at the point of cable application lies between -1 and since excessively high voltages may be encountered in the case of ground faults. The resultant intensity of discharge may be sufficient to cause burning of the insulation or jacket.
So which method is more correct? The formula you picked up from P is destined for: Corrugated tape, longitudinally applied. These formulas are shown also in: As a guide in preventing such serious damage, maximum allowable icez circuit temperatures that damage the insulation to a slight extent only, Industrial Drive P-54-482, South Carolina Phone: I came up with 7. Register now while it’s still free!