An Improved Merging Unit Model forSubstation Automation System Based onIEC61850

[摘要] The implementation of the IEC61850-9-2 standard in substation automation systems requires the use of merging units for elimination of several multiple wire connections running from the switchyard to the microprocessor relays located in the control room. The conventional merging unit model collects current and voltage signals from various current and voltage transformers in the switchyard, converts them into digital form and sends the digital equivalents to the microprocessor relays via a single fiber optic cable known as the process bus. In this paper, we proposed a new merging unit model with additional features of in-built overcurrent protection and bay control functions. This new model is intended to provide local over-current protection and bay control for all equipments in the bay being monitored by a particular merging unit.

[关键词] Merging Unit;Substation Automation System;IEC61850;Process Bus.