There are currently various types of tracer wires on the market, such as copper clad steel, copper core PVC insulated cables (hereinafter referred to as copper core wires), copper clad aluminum, and so on. Which tracing line is better and more conducive to long-term tracing and positioning management of buried gas pipelines? It is necessary to test the performance of the tracing line in order to choose a more suitable tracing line. Therefore, we conducted tests on the commonly used tracer lines for the three types of PE gas pipelines mentioned above, providing reference for the selection of tracer lines for PE gas pipelines in terms of their conductivity, anti-corrosion treatment of tracer line joints, and strength.

示踪线的测试原理

Testing principle of tracer lines

铜包钢是由钢芯线和紧密包覆其外的铜层构成金属芯，外侧为PE防腐层，铜起到传导弱电信号的作用，钢丝则起到支撑作用。铜芯电线一般由内层的铜芯线、中间层的绝缘包皮和外层的保护外皮组成。铜包铝由铝芯线和紧密包覆其外的铜层构成金属芯，外层为PE防腐层。

Copper clad steel is a metal core composed of steel core wires and a tightly wrapped copper layer, with a PE anti-corrosion layer on the outer side. Copper plays a role in conducting weak electrical signals, while steel wire plays a supporting role. Copper core wires are generally composed of an inner layer of copper core wire, an insulating sheath in the middle layer, and an outer protective sheath. Copper clad aluminum consists of an aluminum core wire and a copper layer tightly wrapped around it to form a metal core, with an outer layer of PE anti-corrosion coating.

由于钢质燃气管道外层的防腐层为具有绝缘、防腐性能的塑料层或涂层，与铜包钢、铜芯电线、铜包铝等外层也为具有绝缘、防腐性能的塑料层结构相似。因此，我们将两者等效，通过采用PCM管道电流衰减率法，对示踪线防腐层平均绝缘质量进行检测。检测原理是向示踪线施加某一频率的电流信号，电流由示踪线向远方传递时会逐渐衰减。其衰减大小与示踪线的塑料层的绝缘电阻率有关，示踪线塑料层的平均绝缘电阻率越高，电流衰减就越慢，反之则衰减越快。

Due to the fact that the anti-corrosion layer of the outer layer of steel gas pipelines is a plastic layer or coating with insulation and anti-corrosion properties, similar in structure to the outer layers of copper clad steel, copper core wires, copper clad aluminum, etc., which also have insulation and anti-corrosion properties. Therefore, we equate the two and use the PCM pipeline current decay rate method to detect the average insulation quality of the trace line anti-corrosion layer. The detection principle is to apply a current signal of a certain frequency to the tracer line, and the current will gradually decay when transmitted from the tracer line to the distance. The magnitude of its attenuation is related to the insulation resistivity of the plastic layer of the tracer line. The higher the average insulation resistivity of the plastic layer of the tracer line, the slower the current attenuation, and vice versa, the faster the attenuation.