A novel approach to microcurrent detection in full-bridge circuits using harmonic signals

Purpose Buried steel pipelines are critical to infrastructure; however, they are susceptible to undetected corrosion, posing safety and operational risks. The current detection techniques often lack sensitivity and accuracy, especially for weak magnetic signals that are affected by environmental noise and material alternations. The purpose of this study is to propose a high-sensitivity, reliable detection method for locating and classifying defects in buried steel pipelines. Design/methodology/approach To address these challenges, a unique micro-differential current detection technology that uses harmonic magnetic fields to locate and classify defects in buried steel pipes. A detector was introduced which has two horizontal excitation coils that produce a magnetic field for buried steel pipelines. The Wheatstone bridge principle uses alterations in surface material at the defect to induce a variation in inductive reactance, disrupting electric equilibrium and producing a microcurrent differential between the two coils. Findings The results reveal the effectiveness of the method at different heights and distances, producing consistent results even in harsh environments. And the technology has the detection effect of increasing height and lifting away, and can effectively identify pipeline defects. Originality/value This portable, high-performance instrument combines differential current measurement with harmonic signal processing to provide a reliable, nonintrusive alternative for pipeline monitoring. This method is adaptable to a variety of working conditions and suitable for long-distance use, offering great potential for improving pipeline safety.