A digitally-controlled, real-time, analog power-system simulator for closed-loop protective relaying testing

A power-system simulator is described that uses a control computer to configure an electronic analog model of a three-phase symmetrical power system and to set the model parameters. The model closely represents the dynamics of the real world up to 3 kHz. Precision high-power amplifiers convert the low-level analog signals to supply the protective relays under test. The design has been influenced by the key feature of closed-loop operation, with the relays functioning dynamically and in real time with the model. Nonlinearities are represented where significant, including the fault, transformer, arrester, and series-capacitor protection modules. The long-line transmission models represent the traveling-wave phenomena. Numerous system configurations can be selected. The data-acquisition system utilizes four digital computers, storing analog data at up to 25 kHz rate. The computers also analyze and manipulate the analog and event data and control a color plotter and printer. The emphasis of the discussion is on the analog models and the power amplifier designs