Power system stability study with dynamic load

Normally loads can be classified into three major types: constant impedance, constant current, and constant power. Each type can cause variations in the characteristics of power system stability swings. The differences in magnitude of swing, frequency of oscillation, and damping factor were investigated. System voltage and frequency swing during disturbances of the system with composite load characteristics were investigated. These investigations lead to an understanding of load behavior with voltage and frequency dependency functions during disturbances and how it should be represented. Comparison runs were made using analytical calculation, digital simulation, and hybrid simulation. An analog load representation that can respond to voltage and frequency variations for the hybrid simulation was implemented. The hybrid simulation techniques are discussed.