To address transient voltage stability and control issues in AC/DC hybrid power systems

a reactive power-voltage zoning method that integrates transient voltage security and network topological characteristics is proposed. First

transient voltage security indices reflecting voltage recovery capability and time margin during faults are defined

along with short-circuit impedance to characterize system topology. Based on these

a transient voltage characteristic distance and a short-circuit impedance distance are constructed

respectively. Then

two initial zoning schemes are formed according to the two distance measures. Nodes that are assigned to the same zone in both schemes are selected to form independent zones (consensus zones)

while nodes that fail to reach consensus form independent zones

thereby yielding an initial zoning scheme that combines both features. Next

an improved hierarchical clustering method is applied to progressively merge highly similar zones in the initial scheme

using the minimum inter-zone transient voltage characteristic distance as the criterion under zoning principle constraints. Finally

the optimal zoning structure is adaptively determined by maximizing the modularity index. The effectiveness of the proposed method is validated through simulations on a modified IEEE 39-bus system.