Medium voltage flame-retardant frequency-conversion power cable

Abstract

The invention relates to a medium voltage flame-retardant frequency-conversion power cable which comprises three cable core wires arranged in parallel and identical in structure. Each cable core wire comprises a circular conductor. A shielding layer, an insulating layer and an insulating shielding layer are arranged outside the conductor in a three-layer co-extrusion manner. The insulating shielding layer is externally covered by an inner layer plastic-aluminum composite belt, an inner copper wire sparse-winding shielding layer, an inner copper-belt wrapping shielding layer and a phase-splitting inner isolating sleeve in sequence. Gaps among the three cable core wires are filled with flame-retardant PP filling ropes and then are externally provided with a cabling layer. The cabling layer is externally covered by an outer layer plastic-aluminum composite belt, an outer copper wire sparse-winding shielding layer and an outer copper-belt wrapping shielding layer in sequence, then an outer isolating sleeve is extruded outside, and aluminum alloy linkage armour serves as the outmost layer for covering. According to the invention, the interference of pulse voltages can be reduced to the lowest level, and the frequency-conversion power cable is enabled to effectively inhibiting the interference of electromagnetic wave.

Description

technical field [0001] The invention belongs to the technical field of power cables, in particular to a medium-voltage flame-retardant variable-frequency power cable. Background technique [0002] The frequency conversion power cable must have strong voltage shock resistance, be able to withstand the pulse voltage during frequency conversion, and must have good shielding, which can effectively eliminate electromagnetic interference, reduce the noise of the frequency conversion motor, and ensure the stable operation of the system. The anti-electromagnetic wave interference and mechanical protection performance of frequency conversion power cables are important factors affecting the performance of cables, and most of the existing frequency conversion cables cannot have excellent anti-electromagnetic wave ability and strong tensile and compression resistance at the same time. [0003] The internal structure of the general variable frequency power cable is mainly composed of thr...

AI Technical Summary

Problems solved by technology

However, due to the interference of pulse voltage, that is, because the frequency adjustment range of the frequency conversion power supply in the frequency conversion system is relatively wide, it contains many high-order harmonics, and the amplitude is also large. Breakdown, and the interference and harmonic voltage generated by the main core and the neutral core are also unbalanced; and there is electromagnetic wave interference, that is, the cable connected to the variable frequency power supply generates electromagnetic waves during operation, which will cause electromagnetic interference to the surrounding adjacent areas. Electromagnetic waves can also interfere with frequency conversion cables

At the same time, the shielding structure of general variable frequency power cables is to use a layer of copper tape wrapped around the cable core. This kind of cable can achieve a certain shielding effect on electromagnetic interference within a certain frequency, but its shielding effect is very low at high frequencies. Difference

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