Challenges with series compensation applications in power systems when overcompensating lines
Series compensation is a cost-efficient way to decrease the line reactance and improve the system stability and increase the transfer capacity for long transmission lines. Traditionally, the maximum degree of compensation has been around 80 %. The necessity to connect renewable electricity sources (e.g. wind and solar power stations) is a driver for installing new substations along series compensated lines. When a new substation is installed along an existing series compensated transmission line, the result can be an overcompensated line, i.e. a line, which has an effective series reactance that becomes capacitive.