Research on Power of Damped AC Voltage While Conducting Simultaneous Three-Phase Partial Discharge Test on 10kV Distribution Cable

The 10 kV distribution cable is extensively used in urban power grids; however, minor defects introduced during the production, construction, and operational phases can lead to partial discharges within these cables. Such discharges significantly compromise the safe and stable operation of the distribution system. Currently, damped AC voltage technology is widely used on-site to detect and locate partial discharge defects in 10 kV distribution cables. With the growing demand for improved efficiency in operation and maintenance, researchers have begun to explore the simultaneous detection of partial discharges across all three phases of distribution cables using damped AC voltage testing systems. The power demand characteristics required for simultaneously detecting three phases are influenced by various factors such as load capacity, insulation resistance, and more. Therefore, this paper analyzes the power characteristics required for simultaneous damped AC voltage testing of three-phase 10 kV distribution cables through simulation. Initially, the working principle of DC charging damped AC voltage is introduced. Subsequently, a Simulink simulation model is constructed based on this principle. The simulation encompasses various scenarios, including single-phase testing, three-phase simultaneous testing, and three-phase simultaneous testing with reduced insulation resistance due to defects. The analysis yields critical data, such as the charging voltage applied to the tested cable, the damped AC voltage waveform, and the charging current from the power supply. Additionally, the study calculates the required boosting time and the power demand characteristics for the three-phase simultaneous test under these conditions, as well as the energy consumed during these scenarios.