Abstract: | Abstract:?At?present,?there?are?many?secondary?faults?in?the?secondary?circuit?of?the?current?transformer?of?the?high-voltage?substation.?The?two-point?grounding?of?the?current?transformer?causes?a?500kV?protection?misoperation?because?500kV?protection?collects?the?currents?of?the?secondary?loops?of?the?two?current?transformers?and?adopts?two-fold.?In?the?three-connection?mode,?when?one?of?the?current?transformers?and?its?secondary?circuit?is?overhauled?and?stopped,?another?current?transformer?and?its?secondary?circuit?are?still?running.?At?this?time,?if?the?risk?control?measures?are?improper?in?the?work,?it?will?lead?to?protection.?Misoperation?caused?grid?accidents.?This?article?summarizes?the?500kV?protection?of?high-voltage?substations?through?the?case?analysis?and?summarizes?the?risk?control?measures?in?the?maintenance?of?the?secondary?circuits?of?the?two?current?transfo |