Protecting a future HVDC network from short
circuit DC faults is presently expected to require extensive imple-
mentation of fast HVDC circuit breakers, allowing for rapid fault
isolation. The requirement for circuit breakers may, however, be
reduced or removed depending on the protection methodology,
resulting in a slower post-fault recovery. The expected fault
response and the subsequent network recovery is dependent
on the circuit breaker, network, and converter configurations.
This paper examines a low speed protection methodology for
a symmetrical monopolar HVDC system, a configuration which
requires pole to pole balancing following a pole to ground fault.
The fault clearance and network recovery timings are therefore
evaluated for both pole to pole and pole to ground faults on
several case study networks.