Load cycle heating method of high-voltage alternating-current cable

Abstract

The invention relates to a cable testing method, especially to a load cycle heating method of a high-voltage alternating-current cable. According to the existing heating method for the alternating-current cable load cycle at the low voltage level, a test loop applies the same heating current as a simulated loop, so that the cable temperature of the test loop is higher than the highest operating temperature. The heating method comprises: obtaining a structural parameter and a material parameter of a cable; establishing equivalent heat circuit models of a test loop and a simulated loop; calculating a simulated loop steady-state current in a highest temperature state of a conductor; constructing a loss equivalent model; obtaining corresponding loss equivalent models of the simulated loop and the test loop; calculating an equivalent dielectric loss current in a steady state; and determining a heating current of the test loop. According to the heating method, the influence on temperature control equivalence of load cycle test and simulation loops by dielectric losses of the high-voltage cable are considered fully; and a phenomenon that the practical temperature of the test loop conductor is higher than that of the simulated loop can be avoided.

Description

technical field [0001] The invention relates to a cable test method, in particular to a high-voltage AC cable load cycle heating method. Background technique [0002] When the AC cable is in load cycle, the conductor temperature of the test loop cannot be directly measured. It is necessary to set up an analog loop to monitor the conductor temperature in real time, so as to control the conductor temperature of the test loop. Therefore, the test circuit applies AC test voltage and heating current, and the simulation circuit only applies heating current. When the voltage level is above 220kV or even 500kV, the test voltage is relatively high, and the influence of the dielectric loss caused by AC high voltage on the temperature rise of the test circuit cannot be ignored. In the current heating method for low-voltage AC cable load cycles, the heating current applied to the test loop is the same as that of the simulated loop, but for high-voltage AC cables, this heating method ig...

AI Technical Summary

Problems solved by technology

In the current heating method for low-voltage AC cable load cycles, the heating current applied to the test loop is the same as that of the simulated loop, but for high-voltage AC cables, this heating method ignores the effect on the temperature of the test loop caused by dielectric loss. l impact

When the current value of the simulation circuit reaches the maximum operating temperature of the cable is added to the test circuit, the temperature of the cable in the test circuit may be higher than the maximum operating temperature, resulting in too harsh test conditions, and even premature breakdown of the test circuit cable. Affect the accuracy of electrical performance verification of cable samples

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