Abstract: When distributed arc-suppression coils operate in parallel, frequency-injection tracking may misestimate the capacitive earth-fault current under coupling, causing tuning errors and delayed tap response. Inductance drift then drives repeated crossings near full compensation, triggering underdamped tuning overvoltage, while fixed damping cannot adapt to resonance drift or varying zero-sequence excitation, leading to recurring limit violations. This paper introduces a controllable neutral damping resistor at the bus and proposes a coordinated coil–resistor mitigation scheme: a driving-point-impedance– based risk index quantifies low-frequency amplification and guides adaptive damping switching, and a low-frequency DC mode extracted from neutral displacement voltage provides an energy metric for operating-condition identification and control adjustment. Simulations show that, in a representative parallel-tuning overvoltage scenario, the peak neutral displacement voltage is reduced by up to 94.7%, and the suppression robustness is improved, supporting practical setting and operation of distributed-compensation systems.