System for monitoring current-carrying capacity of cable conductor and method

Abstract

The invention provides a method for monitoring the current-carrying capacity of a cable conductor, which comprises the following steps of: firstly, monitoring the temperature of an outer sheath layer of the cable conductor and current of a cable core of the cable conductor; deducting the cable conductor into a conductor layer, a conductor shielding layer, an insulating layer, an insulated shielding layer, a cushion layer, an air gap layer, an aluminum sheath shielding layer and an outer sheath layer in advance according to the heat transfer characteristic of the cable conductor; acquiring the heat resistance of each layer for the cable conductor and the loss generated by each layer for the cable conductor according to the heat conducting performance of each layer of material of the cable; acquiring the temperature of the cable conductor by using a node method according to the heat resistance, the loss, the outer sheath layer temperature of the cable conductor and the current of the cable cote of the cable conductor, wherein the temperature of the cable conductor comprises the steady temperature and the transient temperature of the cable conductor; and monitoring the current-carrying capacity of the cable conductor according to the temperature of the conductor cable. The invention further provides a device for monitoring the current-carrying capacity of the cable conductor. According to the method and the device, disclosed by the invention, the temperature of the cable conductor can be monitored in a real time.

Description

technical field [0001] The invention relates to a temperature measurement technology of a cable conductor, in particular to a system and a method for measuring the temperature of a cable conductor. Background technique [0002] The most direct characteristic quantity of the amplitude change of the ampacity of the power cable conductor is the temperature change of the conductor. Once the transient and steady-state temperature of the cable conductor is determined, it is easy to determine the transient and steady-state ampacity of the power cable line, but the direct measurement of the cable conductor There are still technical difficulties with temperature. [0003] At present, the cable ampacity is determined by means of thermocouples or continuous measurement of the outer surface temperature of the power cable line, and then the conductor temperature is determined according to the method provided by the IEC standard to obtain the conductor temperature through the cable outer ...

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Problems solved by technology

[0005] However, the method for determining the transient and steady-state temperature of the cable conductor provided by the current IEC standard has the following defects: because the standard is based on the following assumptions: 1. The surface of the earth is an isothermal surface; 2. The surface of the cable is an isothermal surface; 3. The principle of superposition Be applicable

Due to these concerns, the current actual use load controlled by the power sector usually does not exceed 70% of the calculated rated value; on the other hand, it is difficult to make a decision due to the uncertainty of various parameters when a large current is loaded during the peak power consumption in summer. Decide

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