Parallel groove clamps are essential components for ensuring the safe operation of power systems. This paper explores the evolution of contact resistance in parallel groove clamps. An experimental setup was built to measure temperature rise and resistance under various operating conditions, complemented by simulation modeling. The results from the simulation were compared with experimental data, showing temperature errors within ±2 °C and contact resistance errors within ±1.5 μΩ. The findings indicate that contact resistance and temperature of the parallel groove clamp increase with higher excitation current. Multi-segment parallel groove clamps demonstrate lower increases in contact resistance and temperature, indicating superior performance.