This paper analyzes the impact of conventional DC and renewable energy integration on transient voltage instability characteristics in receiving-end power grids and proposes a measurement-based real-time transient voltage stability criterion. First

based on the partitioning characteristics of voltage dynamic responses

an aggregate model is used to represent the average voltage response of the receiving-end grid. Key electrical characteristics of load-dominated voltage instability are extracted

leading to the proposal of an "active power decline-reactive power rise" instability criterion. Second

by incorporating the equivalent impedance of DC systems

Thévenin equivalence is used to analyze the impact of different DC power levels on load voltage stability. DC power monitoring is introduced to address misjudgments caused by the slow recovery of DC systems. Furthermore

the characteristics of active and reactive power variations in renewable energy sources under low-voltage conditions are examined

and an improved transient voltage instability criterion is proposed considering renewable energy integration. Finally

simulation results from a practical AC-DC receiving-end power grid demonstrate that

compared with the power-current method and voltage integration method

the proposed approach accurately identifies voltage instability under various operating conditions.