CP1519 ‘Treatment of Low Capacity Connections for Site Specific Line Loss Factor Calculations’

Formal title: Treatment of Low Capacity Connections for Site Specific Line Loss Factor Calculations

Summary

Line Loss Factors (LLFs) are calculated and applied to Metered Volumes to account for distribution losses. LLFs are calculated on an individual basis for sites connected at Extra High Voltage (EHV) and on a generic basis for other connections.

There are an increasing number of EHV Sites with a ‘main’ connection and a subordinate small-scale connection. The subordinate connection is often 1 MVA or less and the majority are ancillary import connections for Generating Plant and Apparatus e.g. to power aircraft avoidance lights on wind turbines when the turbine is not Generating its own power. Subordinate connections have low maximum demand and consumption and, if they were single connections in their own right, would be connected at lower voltage levels with generic LLFs.

CP1519 proposes to apply generic losses appropriate to the voltage of connection to sites with a capacity less than 1 MVA. There are already voltage boundary limits to qualify as EHV; this could be extended to applying a capacity boundary (e.g. low capacity sites less than 415V) as a proxy for determining subordinate connections. This would formalise a default replacement process for low consumption sites within Principle 17 of the LLF calculation principles.