Investigations into feasibility of a modified woodpole distribution structure to reduce pole-top fire risk

Summary

The feasibility of a modified partially bonded woodpole line structure with a downwire insulator instead of the 500 mm gap along the wood in limiting the risk of pole-top fires and bird electrocution was investigated. Preliminary results of the tests performed in a naturally polluted environment were reported previously and encouraging. This paper details the results of laboratory tests conducted to confirm previous findings. The results indicate that the impedance of the downwire insulator is sufficiently low (in order of tens k?) under conducive conditions to conduct leakage current to earth effectively, with very little current (<< 1 mA) flowing through the wood generally. Such low levels of currents may not be sufficient to cause wood burning to occur (experience shows that sustained currents in order of 1 mA are adequate), indicating that the modified structure may limit the risk of pole-top fires. The downfall is that the impedance of the downwire insulators may not be adequately high to ensure acceptably low risk of bird electrocution under the same conditions.

Additional informations

Authors

Lin Fuchang, Xu Zhijian, Sun Haofei, Zhang Qin, Anglhuber Martin, Freiburg Michael, Shimonosono