Definition and Analysis of Receiving System Voltage Support Strength Factor

Based on the analysis of the relationship between the voltage sensitivity of the receiving system and the DC power stability, an evaluation index, Receiving System Voltage Support Strength Factor (RVSF), is proposed in this paper for identifying the voltage support strength of the receiving system. The threshold of RVSF is derived and used as the criteria for distinguishing the voltage support strength of the receiving system. The critical Receiving System Voltage Support Strength Factor (CRVSF) can keep constant in receiving systems which operate in different modes. Furthermore, the analytical expression of RVSF is derived from the Jacobian matrix form of the incremental flow equation of the AC system. By deriving the relationship between RVSF and power stability and considering the constraint of commutation angle, it can be obtained that the receiving system is a very weak system when RVSF<;0.60, a weak system when 0.60<;RVSF<;2, and a strong system in case of RVSF>2. Finally, the performance of RVSF and other widely used system strength indicators such as effective short circuit ratio (ESCR) and multi-infeed effective short circuit ratio (MIESCR) are compared and analyzed. Compared with other indicators, it is found that RVSF has a clear threshold when measuring the strength of different receiving systems.