When the internal components of capacitor break down

the capacitance of capacitor bank will change accordingly

which will lead to the deviation of neutral point voltage and the generation of unbalanced current. Firstly

the calculation formula of bridge differential protection of compensation capacitor bank in power system is deduced

and the single star connection form of capacitor bank is sorted out. And then

the Simulink simulation model is established by Matlab with examples

and the operation of capacitor banks under different breakdown rates is simulated and analyzed. Finally

the derived formula is verified by simulation data.