NG TS 3.24.101
National Grid Technical Specifications - Merging Units
|Publication Date:||1 May 2018|
PURPOSE AND SCOPE
Conventional NG Protection and Control practice is for direct point to point hard wired connections between the primary plant interfaces (Conventional Instrument Transformers (CT/VTs) and digital Inputs/Outputs(I/O) used for monitoring and control) and Intelligent Electronic Devices (IEDs). This approach does not easily facilitate secondary system upgrade or replacement without securing a long primary circuit outage of the bay or substation.
IEC 61850 (bay) Process Bus technology has the potential to significantly reduce the required wiring work. Such installations would then use Merging Units (MU) as common plant interfaces and distribute digitised analogue and digital data to the respective control, protection and measurement IEDs via fibre networks. The perceived benefits of this approach being the reduction in replacement time and costs for both systems and IEDs, and in the longer term interchangeability between different manufacturer's offerings as a result of a well-defined interface.