Voltage stability analysis of power system with uncertain load characteristics

One of the major factors defining voltage stability limits of an electrical power system is electrical load characteristics. Since any detailed information on complex load composition at the system buses is usually absent for a constantly changing power demand, there exist large parametric uncertainties in the electrical load representation. In order to determine a whole set of electrical load parameters, for which power system voltage stability is preserved, robust control theory was applied in the present paper. A new method exploiting a zero set concept was derived to determine the required set in parameter space. A particular definition of the zero set adopted in this paper allows one to obtain its boundary in a totally analytical, straight forward way.