The main products of the control cable are polyvinyl chloride insulated control cable natural - styrene butadiene rubber insulated control cable and polyethylene insulated control cable three series. In addition, there are crosslinked polyethylene insulation and ethylene propylene rubber insulation products. The oil-impregnated paper-insulated lead-covered control cables produced in the early years have been eliminated. In order to ensure that the control cable in the event of insulation breakdown, mechanical damage or fire, reduce the scope of the spread, the national standard GB50217-91 "Electric power engineering cable design code" stipulates: dual protection of the current, voltage and DC power supply and trip control loop need to enhance the reliability of the two sets of systems, should use their own independent control cables.


After the control cable is put into operation, there is electrical interference between different cores of the same cable and between cables adjacent to parallel laying. The main reasons for electrical interference are:

(1) Electrostatic interference due to the application voltage on-line capacitive coupling between cores;

(2) electromagnetic induction interference due to on-current. In general, when there is a high voltage, high current interference source in the vicinity, the electrical interference is more serious, because the distance between the core of the same cable is small, the degree of interference is much greater than the adjacent cable laid in parallel.

For example, an ultra-high voltage substation split phase operation circuit breaker control loop, three phases with a cable, there has been such an accident, by the split phase operation of the pulse to trigger other phases of the thyristor, resulting in three-phase linkage, after the use of separate independent cables, there is no misoperation accident. Another example is the computer monitoring system of a power plant, because the analog low level signal line and the transmitter power line are combined with a four-core cable, which has caused 70V interference voltage in the signal line, which will obviously affect the normal operation of the low-level signal loop measured in millivolts.

The measures to prevent or reduce electrical interference are mainly in the following three aspects.

1. Practice has proved that when a spare core of the control cable is grounded, the amplitude of the interference voltage can be reduced to 25%~50%, and the implementation is simple, and the cost of the cable is not increased.

2, the circuit that will have serious consequences for electrical interference is not suitable for a control cable. These include:

(1) weak signal control loop and strong signal control loop;

(2) low level signal and high level signal loop;

(3) AC circuit breaker phase operation of each phase of the weak current control loop, should not use the same control cable. However, if each pair of round trip wires of the weak current loop belong to a control cable that is not the same, a ring arrangement may be formed when laying, and the potential will be induced under the electromagnetic line cross chain of the similar power supply, and its value may have a greater impact on the low level parameter interference of the weak current loop, so it is appropriate to use a control cable for round trip wires.

3. The metal shield is grounded with the shield layer

Metal shielding is an important measure to weaken and prevent electrical interference, including total shielding of wire core, separate shielding and double-layer total shielding. The selection of the metal shield type of the control cable should be included in the comprehensive interference suppression measures according to the strength of the possible electrical interference influence to meet the requirements of reducing interference and overvoltage. The higher the requirements for anti-interference effect, the greater the corresponding investment, when the use of steel tape armor, wire braided total shielding, the price of the cable increased by about 10% to 20%.

Qingdao Tianxing Cable Co., Ltd. is a technology enterprise specializing in the production of wire and cable in Shandong Province, with more than 150 sets of domestic excellent cable production equipment and testing equipment, excellent production technology, modern testing equipment, to ensure stable product quality and timely supply. The company's main products are power cable, mineral cable, high life wire and cable, radiation crosslinked cable, control cable, computer cable, photovoltaic cable, communication cable, data cable, low smoke halogen free cable, flame retardant series wire and cable.