Study of voltage stability for HVDC transmission systems
The status quo of the voltage stability study for the HVDC transmission system is discussed in detail,and the defects of the current study methods are pointed out.Based on the application achievements of bifurcation theory to the voltage stability study for AC systems,it is proposed that the bifurcation theory can also be applied to the voltage stability study for HVDC systems.The difficulties in application of the theory to voltage stability study for HVDC systems are put forward,as well as relevant solutions.
No matter the size of the hydro plant, if it has a long waterway and will operate in peaking mode, the project designer needs to address the issue of hydraulic transients-known as water hammer-early in the design. This article describes the application of transient analysis to the design of a 20-MW hydro plant in California. In this case, a Howell Bunger valve was used as a pressure regulating valve to control transient pressures and speed rise.