Fault Locating Using TDR Synchronized with the Phase of Supply Voltage on Overhead Distribution Lines

TDR pulse injection, posing design challenges.

We propose a method that injects pulses synchronized to the phase of a 6.6 kV supply and locates faults by differencing waveforms near the zero crossing and near the peak, using only fault-period data. Because phase-synchronized injection increases the risk of pulse interference when multiple devices operate, the injection phases are also staggered among devices to prevent mutual interference. This enables arc-fault location immediately after fault inception using only the fault-period waveforms.

We validated the proposed method on a test line and assessed its utility and accuracy. With a 6.6 kV, 50 Hz supply (≈20 ms period), the phase was shifted in 1 ms steps and recorded 90 samples per fault (≈4.5 cycles) of reflection during the fault. The measurements confirmed that the reflection near the zero crossing matches the healthy waveform.

Next, by shifting the injection phase of one unit, it was verified that offsetting the phase angle by at least 3° prevents interference from TDR pulses of another unit. Using the differences between healthy and fault reflections, each device achieved a location error within 10 m. Thus, tests confirmed high-accuracy fault location with the proposed method.