High proportion of external power in the area plays an important role in promoting energy conservation and emission reduction in the receiving-end power system and

at the same time

weakens the regulation ability of the receiving-end system during the peak-load period and

in case of DC lock fault

causes great impact to the receiving end grid. The energy storage device has the characteristic of flexibility and controllability and

in case of DC lock fault

can inject active power

provide virtual inertia for the system and support the system frequency stability. Considering the access of large-scale energy storage devices will affect the system power flow and

at the same time

will generate coupling with the existing conventional generation units and other regulation resources in the system

it will

in the event of DC lock fault

have a complex impact on the emergency support of the system. In this paper

the equivalence construction at certain practical industry-area power grid is performed to study its frequency stability in dealing with DC lock fault. In case of emergency DC lock fault of the system

it is proposed to optimize the parameters of the dead-zone and charge-to-discharge ratio of the emergency active-power support strategy and adjust the time and power of switching on/off of the storage device and the optimal strategy with comprehensive consideration of life of the storage device and frequency adjustment effect is concluded. Finally

the proposed optimization method is verified in the equivalent grid and the corresponding emergency active power support strategy of the storage device is proposed.