Doubly-fed induction generator(DFIG)based wind farms with line-commutated converter based high voltage direct current(LCC-HVDC)integration are not able to startup as usual without voltage support on the sending-end AC bus. Besides

the whole system cannot operate stably with conventional control algorithms. This paper proposes a strategy for the system black startup and integration operation

which includes three critical parts: circuit topology based on distributed energy storage

startup sequence and control algorithm. In the circuit topology

the energy storage configured at the DC link of several wind turbine converters provide energy to startup the system. Thereby

the startup of DFIG based wind turbines is accomplished in the no-load startup mode. After integrated to the HVDC rectifier substation

the proposed reactive power based frequency control is applied into the wind turbine converters whereas the active power based voltage control is used in the HVDC rectifier

jointly maintaining both the voltage and frequency stability of the sending-end AC bus. The simulations on PSCAD/EMTDC indicate that the black startup of the system can be realized successfully

and both the voltage and frequency stability under normal operating conditions can be maintained

which verifies the effectiveness of the proposed strategy.