控制电缆弱磁场分布特性分析

Analysis of weak magnetic field distribution characteristics of control cable

针对目前控制电缆传输空间紧张与电缆隧道内磁场复杂的的问题,基于解析计算、数值计算和现场实测相结合的方法,以发电厂常用的四芯控制电缆(450/750 V)为计算对象,分析了控制电缆工频磁场特性及控制电缆注入特定信号后的磁场分布特性,讨论了芯线注入和铠装注入两种注入信号方式下的磁场特性,通过数据对比得出最优信号注入方式。结果表明,控制电缆正常工作时产生的工频磁场强度在标准规定的曝露安全限值以内;控制电缆路径检测系统的注入信号与正常工作的控制电缆之间不会相互产生影响;不同信号注入的方法中芯线注入信号的方式产生的磁场更稳定,电缆路径检测系统的接收装置更容易检测到信号。对实际控制电缆隧道内的磁场进行现场测量,所得数据与仿真计算值吻合较好。

In view of the present control cable tension and cable tunnel transport space magnetic field of complex problems, this article is based on analytical method, numerical calculation and field measurement, the method of combining with power plants commonly used four core control cable(450/750 V) for computing object, analyzes the characteristics of power frequency magnetic field control cable and control cable into a specific signal after the magnetic field distribution features. The magnetic field characteristics of two signal injection modes, core wire injection and armored injection, are discussed and the optimal signal injection mode is obtained through data comparison. The results show that the strength of the power frequency magnetic field generated by the control cable is within the safety limit of exposure stipulated in the standard. The injected signal of the control cable path detection system does not affect each other with the control cable in normal operation. In different signal injection methods, the magnetic field generated by core wire injection is more stable, and the signal is more easily detected by the receiving device of cable path detection system. The field measurement of the magnetic field in the actual control cable tunnel shows good agreement with the simulation results.