Controlled line commutated converter (CLCC) is a type of flexible current source converter

which has the controllable turn-off capability

and can eliminate commutation failure caused by AC system faults; Valves in CLCC can be turned off without relying on reverse voltage within the turn off angle λ

and can operate for a short period a state where λ is 0 or even negative

so it can flexibly control reactive power. By studying the principle of reactive power control in CLCC

it is concluded that adjusting the CLCC trigger angle α has the same effect as adjusting the excitation current of synchronous generators. The variation of active and reactive power output by CLCC with the trigger angle α is studied. If the reactive power output by the AC filter field is taken into account

the CLCC inverter station can provide a very considerable amount of reactive power to the receiving AC system; In practical engineering

the DC system adopts a constant DC voltage control strategy

which can flexibly control the output reactive power of the inverter station while maintaining a constant DC power as much as possible. The mechanism of fault current conduction between the DC and AC sides during AC system faults was studied

and the similarities and differences of short-circuit current injected into the AC side by CLCC and LCC were compared.