隧道敷设高压电缆特征导纳模型及局部放电信号幅值分布特性

摘要

为了研究交叉互联电缆中局部放电信号的幅值分布特性,基于Tylavsky公式建立了隧道内三相电缆系统的参数化特征导纳模型,利用该模型计算得到局部放电脉冲电流在交叉互联线上的幅值分布公式.研究了电缆的敷设方式和隧道环境对幅值分布的影响.最后通过模拟实验和现场数据验证了所提模型和结论的正确性.研究结果表明:信号幅值分布由特征导纳比值决定且呈现“两大一小”的特点;随着电缆中心间距、电缆中心距隧道内壁距离的增大,三相幅值差异逐步减小.%In order to study the amplitude distribution of PD(Partial Discharge) signals in cross-bonded cables,a parameterized characteristic admittance model of three-phase tunnel-installed cable is established based on Tylavsky's formulas to calculate the amplitude distribution of PD pulse current on the cross-bonded cables.The influences of cable laying mode and tunnel environment on the amplitude distribution are studied.The accuracy of the proposed model and the correctness of the obtained conclusions are verified by simulation experiments and field tests.Research shows that,with the characteristic expression of "two-larger-one-smaller",the amplitude distribution of PD signals is decided by the characteristic admittance ratio;the amplitude difference among three phases is reduced along with the increase of the space between cable centres and the distance between the cable centre and the inner wall of tunnel.