ground potential rise of multi-grounded neutral and shield wires in joint systems

power line faults create the ground potential rise (gpr) on both the neutral and shield conductors when the transmission lines (tl) and distribution lines (dl) are built on the same structures. the durations and magnitudes of resulting gprs are unique for dl faults and tl faults because the corresponding fault currents are significantly different in terms of their magnitudes and durations. this paper analyzes and compares the safety impacts of tl faults and dl faults in the joint structures. approximate formulas are established to describe the gpr characteristics. computer simulation results are provided to illustrate the effects of different parameters on gprs in various configurations.