Voltage Stability Bifurcation Analysis for AC/DC Systems with VSC-HVDC

Table 1

System parameters of operation and control modes of VSC-HVDC.

Operation modes	Control parameters of VSC converters (p.u.)
	VSC1	VSC2
1	Constant DC voltage 𝑈^refd1=2.0000	Constant AC active power 𝑃^refs2=−0.8993
	Constant AC reactive power 𝑄^refs1=0.1220	Constant AC reactive power 𝑄^refs2=0.1734
2	Constant DC voltage 𝑈^refd1=2.0000	Constant AC active power 𝑃^refs2=−0.8993
	Constant AC reactive power 𝑄^refs1=0.1220	Constant AC voltage 𝑈^refs2=1.0186
3	Constant DC voltage 𝑈^refd2=1.9863	Constant AC active power 𝑃^refs1=0.9194
	Constant AC voltage 𝑈^refs2=1.0186	Constant AC reactive power 𝑄^refs1=0.1220
4	Constant DC voltage 𝑈^refd2=1.9863	Constant AC active power 𝑃^refs1=0.9194
	Constant AC voltage 𝑈^refs2=1.0186	Constant AC voltage 𝑈^refs1=1.0203