Research On Distribution Network Preventive Control Based On The Evaluation Of Cable Ampcity

In the distribution network, the mainly performance about equipment defects which willlead to partial invalidation, is the allowed maximum ampacity reducing in a significant way. Ifit keeps running in the normal way, the equipments completely damaged and will affect thenormal power supply of partial load possibly result from the overload in the period of peakload. It is one of the commonest breakdown conditions that caused by cable defects.In order to find the early detection of cable defects, and find out sick cable sequentially,the cable temperature measurement technique becomes mature and promotes itspopularization and application. According to the online monitoring results of the abnormaltemperature rise of the cable line, we can assess the operational risk in a period in the futurebased on forecasting results of load by calculating the maximum allowable under the sickcable. For greater risk situation, preventive control measures can be adopted through theDistribution Automation System to reduce the load level of sick cable by transferring the load.In that way, it could avoid the risk of a permanent malfunction from the damage caused byload peaks.In order to achieve the distribution network of prevention controls, calculating themaximum ampacity and measuring the load current value of cable load are necessarily needed.Distributed Temperature Sensing has been used in this paper to measure the cable skintemperature and assess the cable ampacity in the present temperature combining the IECformula. In this approach, the influence of the external circumstances of thermal of cable hadbeen ignored, and the calculation process had been simplified to improve the computationalefficiency. For the load current value that had been measured, we could use the trendconstraint relations decided by network topology and the operational ways, to identify andcorrect the bad data of distribution network. This method improves the reliability of the cableload current value that had been measured. Under the circumstance of only a few cases of baddata existed they can be corrected to improve the reliability of the data object demonstrated in the numerical examples.In this paper, the overload factor of distribution network cable running is defined on thebasis of these studies. The network reconfiguration method, which the minimum overloadfactor of sick cable as its target, has been proposed of prevented control. The preventivecontrolling target could be achieved just as the example shows, based on the cable capacitywhich is a constraint in network reconstruction, while reducing sick line load, other normalcable could continue regular work.