gui chao cable news: note the power cable laying and laying (2017-非凡电子娱乐

some customers in the design of low and medium voltage power cable in the process of actual power cable ampacity and load flow theory in understanding the existence of errors, often think that the power cable selection as long as the actual operating capacity of equipment can be, and often ignore the actual conditions of cable laying operation correction ampacity of cable accident occurred, hidden danger.

a new silicon industry company, more than 50 10kv power cable factory internal transmission, all alone through the thick white pvc plastic pipe, without gap free stacking of 5 stacked, and then buried in soil, buried depth of about 1 meters, the number of power cable laying of each layer is 10, the cable duct in distribution the basic section underground a rectangular arrangement, a total length of about 1 km of cable line. there are two cable wells in the middle of the cable joint, which is convenient for the maintenance of the cable line. these cables run continuously for 1 days or so, from the mouth of the cable from the mouth of the unpleasant smell due to the decomposition of the cable plastic hot coke taste, less than a week on the power cables have a thermal breakdown. eventually led to the entire 10kv power cable lines can not be used properly. the occurrence of the above problems is a typical case of the power cable accident which is lack of scientific understanding of the actual operation of the cable. low voltage power cable specifications of the various models have an ampacity calculation theory, but the actual laying of power cable used, must fully consider the actual use of the thermal resistance of laying environment correction coefficient of the actual carrying capacity of power cable in the cable used for correction, this design stage before construction must be fully considered otherwise, once the power cable construction, will not be able to remedy the loss caused by the huge economic power. a plurality of cables into pvc plastic pipe, seamless random stacking buried, environmental resistance coefficient of each power cable with power cables directly buried way greatly increased. in the actual operation process of power cable, is located in the discharge pipe of each cable inside the surrounding medium is mainly plastic pipe and adjacent cable, rather than the pure soil, its thermal resistance will be far greater than the soil; heat and power cables in the operation are also constantly on the plastic tube and around the cable in the heating, at this time the actual power cable laying environment is not simply directly buried, the actual operation will be greatly reduced to allow cable ampacity, thermal breakdown accident is inevitable. therefore, in the initial design of cable laying project, the actual thermal resistance of cable laying must be taken into account, and the design should be corrected in time.

when a plurality of power cables are randomly stacked side by side gapless accumulation after a direct burying, when the power cable fault may be adjacent to one or more of the cable joint burned, spreading and expanding the cause of the accident. at the same time, it will lead to the occurrence of thermal breakdown. power cable buried root number too much for cable fault maintenance excavation unfavorable, because the cable number, the excavation process of mechanical damage caused by the cable opportunities will greatly increase, at the same time in the excavation of fault cable, power cable may have adjacent energized, electric shock accident and two power outages are may expand.

for a plurality of power cables are buried at the same time, the number of roots can best control in 6 below, as far as possible in the process of laying distance, give enough space for heat dissipation of power cable in the cable, when choosing to heat performance of the surrounding soil or sandy soil considered, correction coefficient of thermal resistance, to ensure normal power cable safety in use, the service life can be brought into full play.