The need for voltage stability analysis in voltage-controlled buses

• Voltage stability analysis in voltage-controlled buses is necessary.
• There is a maximum power that can be injected by a generator into the grid.
• The effect of voltage control i.e. whether expected or inverse, needs evaluation.
• The size of new generation may have to be limited to assure correct voltage control.

This paper addresses the need to perform voltage stability analysis in voltage-controlled buses. The theory that identifies the existence of a maximum power that can be injected by a generator or compensator into the grid is presented. It is also argued that it is necessary to evaluate the effect of voltage control i.e. whether it produces the expected or inverse effect. The reason for the possibility of having an opposite relationship between the excitation and the terminal voltage is explained. An index relating the two voltages is also presented. A real life illustrative example is provided.