Limited case studies on MTDC operational issues have also
been carried out, for example, DC fault [21] and transient
DC over-voltage caused by the loss of converters [22]
because of the delay in system response. In [23], the
authors proposed a simple four-terminal MTDC system
and the use of coordinated droops to ensure proper power
sharing whereas in [24], three DC grid management
strategies were proposed and their control principles were
outlined. However, only a brief description on the operation
of the third control mode was provided and no study has
been conducted.
generators [18].