Research on Strong Polarization Detection Technology for Grounding Electrode Condition Diagnosis

This study proposes a novel corrosion detection technology for grounding electrode feed rods based on the strong polarization method. By injecting a 1A-level polarization current into the grounding electrode and measuring its voltage decay characteristics, a quantitative relationship between the time constant (τ) and the corrosion degree of feed rods was established. Experiments were conducted using three types of feed rod samples: 1.5m (intact), 1.0m (partially fractured), and 0.5m (severely damaged), under long-term monitoring at a burial depth of 4.5m. The results show that the intact feed rod exhibited the smallest initial time constant (1.17×10⁻⁵s), while the partially fractured and severely damaged samples showed increased values (2.17×10⁻⁵s and 6.04×10⁻⁵s, respectively). Over time, all samples demonstrated a growing trend in time constants (e.g., the intact sample increased to 9.67×10⁻⁵s after 45 days), confirming performance degradation due to soil erosion. The proposed technology, utilizing bipolar square-wave excitation and a specially designed reference electrode, overcomes the limitations of traditional sampling methods that require power outages and excavation. This research provides a new non-destructive testing method for assessing the condition of grounding systems in power networks, offering significant engineering value for preventing equipment failures caused by grounding deterioration.