Detecting impurities that lead to electrical cables outages using laser sensing

This study provides the causes of underground power cables failures in the Eastern region of Saudi Arabia have been investigated. The major cause for these outages has been identified as the quality of cable, play major role in these outages. Due to moisture in the soil across red sea and Arabian region, the cables outages problem is aggravated. This is due to water penetration into the plastic insulated multi-conductor cables which can seriously effect the electrical properties of such devices/or conductors. The problem of water penetration is amplified when the cable is positioned underground or in a high humidity environment. The impurities of ionic species like Na, Mg, K in the insulating layer of cables under moisturized soil could enhance the tree formation process and could cause breakdown between conducting part and the earth. A laser senor based on laser-induced breakdown spectroscopy (LIBS) principle was developed for the measurement of sodium and chlorine which exist in cables and those impurities responsible for absorption of water and water tree formation. For quality testing of different kinds of cables manufactured in the Kingdom of Saudi Arabia of various samples such as faulted cables, new manufactured and even the raw materials like PVC used for insulation were analyzed by using the LIBS. For spectroscopic analysis of cables the plasma was generated by focusing a pulsed Nd: YAG laser at 1064 nm (1 J, 8 ns, 10 Hz) on the polymer cable samples. The LIBS results were compared with the results obtained using standard analytical technique such as inductively coupled plasma emission spectroscopy (ICP). The relative accuracy of our LIBS system for various elements as compared with ICP method is in the range of 0.03-0.6 at 2.5% error confidence.