In modern power systems, communication between multiple Intelligent Electronic Devices (IEDs) has opened up a number of new applications to protection, automation and control of substations. Many system operators are concerned about the reliability of this digital transition, specifically the complexity and the reliability of the protection in these digital substations. The IEC 61850 standard is the likely communication protocol for these substations; however, it still faces some issues regarding interoperability and reliability. Therefore, it is valuable to examine the reliability of the information exchange between IEDs, particularly fault triggered events transported through GOOSE-messages and analogue data sampling through Sample Values (SV). One important task within a reliability assessment is to evaluate the consequences of selected failure modes. This paper presents different failure cases in the overall communication network and proposes a practical evaluation of an IEC61850-based protection scheme under a selected failure condition. The paper reviews reliability requirements for a digital substation with regards to the operation speed and dependability. Tests are performed in a real-time simulation environment to which IEDs are physically interfaced. Performance data is statistically analysed to produce likelihood curves of the operation time to evaluate the reliability of the protection scheme.
R. Loenders, D. Van Hertem, J. Beerten, G. Chaffey, L. Yang, Presented at the 15th International Conference on Developments in Power System Protection, DPSP, Liverpool, 9 - 12 March, 2020
KEYWORDS: digital substation, reliability, IEC 61850, protection