根据导体温升特性实现高压单芯电缆动态增容的实验研究

为了动态增加运行电缆的输送容量,在分析动态增加运行电缆输送容量的必要性后提出了实现电缆动态增容的方法,并模拟电缆的隧道敷设环境设计了110kV交联聚乙烯单芯电缆的正常负荷、满负荷、超负荷等阶跃电流温升实验。分析发现:实验得到的电缆导体温升时间与理论计算得到的导体温升时间基本相符;电缆增加的容量在电缆正常负荷运行范围内,根据供电需求可以长时间对电缆进行动态增容;电缆由正常容量增加到电缆满负荷运行时,在导体温升时间范围内,电缆导体温度达到的最大数值为87%额定工作温度,因此也可以根据供电需求长时间动态增加电缆的容量;电缆由正常容量增加到电缆超负荷运行时,当电缆超负荷20%,电缆运行约50%导体温升时间后,电缆导体温度才达到额定工作温度。因此,利用电缆的导体温升时间,可以动态增加电缆的输送容量,甚至可以让电缆处于满负荷或者超负荷的运行状态。这对电缆线路负荷优化、电力调度以及相关工程实践具有参考意义。

Experimental Research of Dynamic Capacity Based on Conductor Temperature-rise Characteristic of HV Single-core Cable

Increasing transmission current capacity of existing power cable transmission lines is of great significance to the implementation of smart grid.In order to add transmission current capacity of operation cable dynamically,by analyzing the necessity of increasing cable transmission capacity,we put forward a way of increasing cable transmission capacity,designed a temperature rising test for step current of 110 kV XLPE under simulated cable tunnel,including normal load,full load,and over load,and analyzed the experimental data.The results show that,the value of conductor temperature rising-time from the experimental data is consistent with that calculated by theoretical model;if increased cable capacity is within the rated load,according to power supply demand,cable current capacity can be increased and operated dynamically for a long time;when cable capacity is increased from normal load to full load,within conductor temperature rising-time range,under steady condition,the max conductor temperature is 87% of rated operating temperature,so cable current capacity can also be added and operated dynamically for a long time;when cable capacity is increased from normal load to over load,if cable capacity is overloaded 20% of rated load,after 50% of conductor temperature rising-time,conductor temperature reaches rated operating temperature,that is,the operating time of over load is about 50% of conductor temperature rising-time cable.Therefore,making use of cable conductor temperature rising-time,we can increase the capacity of cable transmission lines dynamically,even may make cable to run in status of full load or over load.The results can give a reference value for optimal load of cable lines,power cable operation and management,and related engineering practice.