Power cable emergency load current carrying capacity detection method and system

Abstract

The invention relates to a power cable emergency load current carrying capacity detection method and system. The method comprises the following steps that: the alternating current resistance, ambienttemperature, conductor temperature and the temperature of each branch layer of the insulation layer of a power cable under a condition that a circuit malfunctions are detected; thermal resistance andthermal capacity between the external surface of the cable outer jacket of the power cable and a soil temperature stabilization point are determined according to the historical operating data of the power cable; the emergency load current carrying capacity calculation model of emergency load time is obtained by using the law of conservation of energy of thermodynamics according to the alternatingcurrent resistance, the ambient temperature, the conductor temperature, the temperature of each branch layer of the insulation layer, the thermal resistance and the thermal capacity; and the maximum current carrying capacity of the power cable with the temperature of the power cable not exceeding set temperature after the emergency load time is calculated. With the method and system of the invention adopted, the maximum current carrying capacity of the power cable under a condition of the emergency load can be detected, and a large amount of experimental resources can be saved. The detection method and system can be more conveniently applied to practical projects.

Description

technical field [0001] The invention relates to the technical field of power cables, in particular to a method and system for detecting the emergency load ampacity of power cables. Background technique [0002] When there is an accident on the transmission line, it is often necessary to switch the load on the original cable to other cables to maintain the normal power consumption of the user, but too much load will cause a large current and increase the burden on the cable. When the insulation of the cable exceeds a certain temperature, thermal breakdown will occur, so it is not feasible to carry out overload operation for a long time; because the grid dispatcher can generally distribute the load scheduling of the original cable before the accident to other parts of the grid within two hours. Therefore, it becomes particularly important to predict the temperature rise of temporarily overloaded cables within two hours under transient conditions. [0003] At present, the dete...

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Problems solved by technology

[0004] Based on this, it is necessary to provide a detection method and system for emergency load ampacity of power cables in view of the existing detection schemes that consume a lot of experimental resources and are difficult to be easily applied to actual projects.

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