Electric cable conductor transient-state temperature determining method and determining device

Abstract

The invention relates to an electric cable conductor transient-state temperature determining method and a determining device, comprising the following steps: initial temperature value is measured, and the initial temperature value is a cable skin temperature value or a protective metal sleeve temperature value; according to the initial temperature value, the cable skin temperature value or the protective metal sleeve temperature value is determined to be unchanged, the transient-state temperature rise of a first cable conductor is determined only under the cable loading action; according to the initial temperature value, the transient-state temperature rise of a second cable conductor is determined under the condition that the cable loading is zero; the initial temperature value, the transient-state temperature rise of the first cable conductor and the transient-state temperature rise of the second cable conductor are summed to obtain the transient-state temperature of the cable conductor, as the transient-state temperature of the cable conductor is obtained by deducing the real-time value of the cable skin temperature or the protective metal sleeve temperature, heat resisting coefficient of surrounding mediums, which is hard to hold in a real-time manner, is avoided, and the effect of external environment factors to the calculation of the cable conductor temperature is castedaway, and the calculating precision of the electric cable conductor transient-state temperature is improved.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to a method for determining the transient temperature of a cable conductor and a device for determining the transient temperature of a cable conductor. Background technique [0002] The temperature of the cable conductor is an important parameter reflecting the normal operation of the power cable. It should not exceed the temperature that the main insulation can withstand for a long time (for example, 90°C when the main insulation material is cross-linked polyethylene), so as to ensure the life of the cable. If the temperature of the cable conductor exceeds the limit value, it will accelerate the aging of the cable, shorten the life of the main insulation, and even cause thermal breakdown due to local overheating, causing cable accidents. Therefore, it is particularly important to monitor the operating state of the cable by monitoring the temperature of the cable conductor. ...

AI Technical Summary

Problems solved by technology

[0005] However, in actual operation, the cable current cannot be kept at a fixed value, but runs under a cyclic load. Therefore, this method in the IEC60583 standard is not suitable for determining the temperature of the cable conductor under this condition. In addition, Due to the complexity of the external temperature rise of the cable, it is difficult to achieve accurate calculations. All these reasons lead to the inaccuracy of the total temperature rise of the cable

Images