Sizing of cables in randomly-filled trays with consideration for load diversity

Journal Article · Wed Jan 01 04:00:00 EST 1997 · IEEE Transactions on Power Delivery

DOI:https://doi.org/10.1109/61.568223· OSTI ID:477183

Leake, H C ^[1]

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1. Arizona Public Service Co., Phoenix, AZ (United States)

Method for demonstrating increased ampacity of cables in trays with loading diversity. Ampacity tables for sizing cables in randomly-filled cable trays are provided in NEMA WC 51-1986 based on a model developed by J. Stolpe which ensures that the maximum cable temperature does not exceed the insulation rating (typically 90 C) under worst-case conditions. The Stolpe model intentionally disregards the reduced heating effect of deenergized or lightly-loaded cables to ensure that all possible hot spot conditions are enveloped. In recent years other methods have been proposed to credit loading diversity in order to justify increased ampacity. However, since they involve certain assumptions about the heat distribution within the cable mass, these methods may fail to identify individual overloaded conductors. This paper describes a simple method which considers the performance of individual conductors while providing a means of increasing ampacity as a result of loading diversity.

• OSTI ID: 477183
• Report Number(s): CONF-960725--
• Journal Information: IEEE Transactions on Power Delivery, Journal Name: IEEE Transactions on Power Delivery Journal Issue: 1 Vol. 12; ISSN 0885-8977; ISSN ITPDE5
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
24 POWER TRANSMISSION AND DISTRIBUTION
AMBIENT TEMPERATURE
CALCULATION METHODS
CAPACITY
ELECTRIC CABLES
HEAT TRANSFER