At present

IEC standard and DL standard has no specific limitation value on the ground resistance of HVDC electrode system

however

in some oversea projects

this value is limited additionally. When the soil resistivity of electrode site is extremely high

the ground resistance will increase as well. Consequently

we list the ground resistances of plenty of as-built HVDC electrode projects

revealing that some projects can operate normally with ground resistance >0.35 ?. Through theoretical derivation and simulation calculation

we analyze the effects of high ground resistance on the steady-state temperature rise

transient temperature rise

step potential

touch potential

loss

and DC bias of the surrounding transformer. Based on Belo Monte Ⅱ UHVDC project Terminal Rio electrode design case

the conclusion can be drawn that high ground resistance will not influence the stability operation of electrode with reasonable design. The comparison of different design cases reveals that canceling the limitation of ground resistance can save engineering costs without impairing the safe and stable operation of electrodes.