Busbar protection is among the most critical functions in substation protection because a bus fault can interrupt multiple circuits at once, damage primary equipment, and rapidly escalate into a wide-area outage. At the same time, substation digitalization has changed the engineering basis of busbar protection. Modern schemes may be hardwired, IEC 61850-enabled, process-bus-based, centralized, distributed, or virtualized, and each architectural choice reshapes not only speed and selectivity but also maintainability, interoperability, and cyber exposure. This review compares centralized and distributed busbar protection schemes and develops a structured framework for dependability and security assessment. The study follows a protocol-driven review methodology focused on literature published between 2020 and 2025, with attention to bus differential protection, process bus design, synchronization, redundancy, interoperability, virtual IEDs, testing, and cybersecurity. The paper finds that centralized architectures provide a coherent system-wide view and simplify some forms of protection coordination, but they concentrate timing, software, and cyber risks. Distributed architectures improve modularity, support phased retrofit, and often degrade more gracefully under isolated failures, but they increase configuration-management burden and interoperability demands. The review argues that architecture alone does not determine performance. Dependability and security emerge from the interaction of differential algorithms, current-transformer behavior, topology processing, network redundancy, sampled-value quality, time synchronization, cyber controls, and maintenance practice. For most utilities, the most resilient pathway is not purely centralized or purely distributed but hybrid: distributed acquisition, deterministic communication, redundant timing and networking, disciplined configuration governance, and hardware-in-the-loop validation supported by IEC 62351-aligned cyber protections. The paper concludes by identifying research gaps and by proposing a practical assessment framework for procurement, FAT/SAT, commissioning, and lifecycle review.
Humayun Rafis (Tue,) studied this question.