control cable

KVV is a connecting wire used for control and protection lines in industrial and mining enterprises, energy and transportation departments, commonly known as control cables. Mainly used in fixed situations with high mechanical tension such as cable trenches, pipelines, and shafts. In this article, Asia Cable will discuss with you the selection and use of control cables.

Main series varieties of control cables

The main products of control cables today include PVC insulated control cables, natural styrene butadiene rubber insulated control cables, and polyethylene insulated control cables. In addition, there are also cross-linked polyethylene insulation and ethylene propylene rubber insulation products. The oil immersed paper insulated lead wrapped control cables produced in the early years have been phased out.

The rated voltage of the control cable is expressed in U0/U. The national standard issued in 1998 in China stipulates that the rated voltage of plastic insulated control cables is 450/750V. Foreign countries have proposed 600/1000V products as the conventional product series for control cables. At present, China can also produce 600/1000V plastic insulated control cables. The rated voltage of rubber insulated control cables is specified as 300/500V.

The control cable core is copper core, with a nominal cross-section of 2.5mm and below, with 2-61 cores; 4-6 mm, 2-14 cores; 10mm, 2-10 cores. Control the working temperature of the cable: rubber insulation at 65 ℃, polyvinyl chloride insulation at 70 ℃ and 105 ℃. The control cables used in computer systems generally use PVC, polyethylene, cross-linked polyethylene, and fluoroplastic insulation products.

Measures to ensure the normal operation of control cables and prevent interference

To ensure that the control cable can reduce the impact range in the event of insulation breakdown, mechanical damage, or fire, the national standard GB50217-91 "Code for Design of Electric Power Engineering Cables" stipulates: current, voltage, DC power supply, and trip control circuit. The two systems that require enhanced reliability should use separate control cables.

After the control cable is put into operation, there is an electrical interference problem between different cores of the same cable and between cables laid in parallel. The main reasons for electrical interference are:

(1) Electrostatic interference caused by capacitive coupling between iron cores due to applied voltage;

(2) Electromagnetic induced interference caused by energized current. Generally speaking, when there are high-voltage and high current interference sources nearby, electrical interference is more severe. Due to the small spacing between the cores of the same cable, the degree of interference is much greater than that of adjacent parallel cables.