Now in many places with a relatively large number of cables that control cable. Well, you know when you install the control cables should pay attention to what? Here, Xiao Bian, I took off in terms of it.

After the control cable in operation, between the same core cables are laid in parallel between adjacent cables of electrical interference problems, the main cause of electrical interference are:

(1) electrostatic interference due under the applied voltage line capacitive coupling between the core of the action generated;

(2) Since the electric current generated by electromagnetic induction interference. In general, when the near presence of high voltage, high current source of interference, electrical interference is more serious, since the distance between the same cable wire core is small, the degree of interference is much larger than the immediate vicinity of the cable laid in parallel. For example, a circuit breaker operation EHV Substation phase control loop, combined with a three-phase cable, such accidents have occurred, the pulse phase of the operation so that other phase thyristor trigger, resulting in three-phase linkage error, later renamed with each separate cable, it does not happen again malfunction. Another example is a computer monitoring system in a power plant due to the low level of the analog signal line and power line transmitter combined a four-core cable, which has caused interference in the signal line voltage of 70V, which is in millivolts the low signal circuit will obviously affect the normal work.

Measures to prevent or reduce electrical interference, mainly in the following three aspects.

1, a backup core control cable grounding: Practice has proved that the control cables a spare core grounding, interference voltage amplitude can be reduced to 25% to 50%, and is simple to implement, while the cable cost increase is minimal.

2, the electrical interference occurs when the serious consequences of a circuit, with a sub-control cable: These include: (1) weak signal and strong signal control loop control loop; (2) low-level signal and a high level signal loop; each phase weak (3) AC operated circuit breakers control loop, should not use the same control cable. But weak loop wire each pair of round-trip is not the same as belonging to a control cable, it is possible to form a ring arranged in the laying, magnet wire under similar cross-linking power will be induced potential, its value may be weak loop low interference parameter greater impact, so the round trip wire should remain a combination of the control cable is appropriate.

3, the metal shield and shield ground: metal shield is weakened and an important measure to prevent electrical interference, including wire core shield, shielding and double type shield and the like. Measures to control the cable metal shield type selection, the strength of electrical interference shall be possible, included in the integrated interference suppression to meet to reduce interference and over-voltage. On the anti-jamming effect of the higher requirements, the corresponding investment greater when using steel armor, when steel wire braided shield, cable price increase of about 10% to 20%.