Generating Detailed Software Models of Microprocessor-Based Relays

Computer models of relays play an important role in evaluating the performance of protection systems during system faults and other disturbances. The use of relay models would enable us to investigate the relays with closed-loop simulations and approximate actual relays´ characteristics so that their performance can be evaluated for a variety of operation conditions. This paper describes a unified approach for computer-based simulation of microprocessor-based relays. The software relay model developed is a detailed digital model, which closely follows the hardware and firmware architecture of the physical relays. The model is employed for testing the performance of the relay with a variety of simulation tests. Results obtained have verified the effectiveness of the presented method and the relay models.