Table 8 Topologies and characteristics of the offshore step-up substation
Topology type | Benefits | Challenges | Complexity |
|---|---|---|---|
AC collection [136] | •  Robust power control realized •  Harmonic voltage reduced •  Common-mode voltage reduced | •  FRT •  Influence of AC frequency on the circuit breaker | **** |
DC series collection [137] | •  Cost loss •  Requirement of DC/DC convert gain reduced | •  Fault protection •  Control of strong coupling •  Working voltage range | *** |
DC parallel connection [138] | •  High reliability •  Flexible operation | •  Requirement of DC/DC convert gain | ** |