Induced Voltage Calculation in Metallic Sheath of Single-Core Cables under Power Frequency Load Current

To address issues of scattered calculation formulas, lack of unified derivation, and difficulty in adapting to complex laying conditions for induced voltage in metallic sheaths of single-core cables, a general calculation model for induced voltage in metallic sheaths of high-voltage cables was established through detailed derivation and analysis. Additionally, the influence of an auxiliary ground wire with a "3:7" arrangement on induced voltage of cable metallic sheaths under normal operating conditions was investigated, and comparative validation was performed against formulas provided in GB 50217—2018 standard. Results demonstrated that the proposed general formulas were completely consistent with scattered formulas in the standard, and could uniformly describe various laying arrangements; the "3:7" arrangement of auxiliary ground wires exerted no effect on induced voltage of metallic sheaths during normal operation. This model could facilitate understanding of the principle and influencing factors of induced voltage generation in metallic sheaths, and derived calculation formulas exhibit enhanced universality, making them applicable to various arrangements under multiple laying conditions, thereby providing a theoretical reference for calculating induced voltage in metallic sheaths of single-core cables.