scope:

PURPOSE AND SCOPE

This Technical Guidance Note details National Grid requirements for the calculation and application of metering errors / compensations for three phase four wire energy meters as used for Settlement Metering purposes.

This version of the TGN has been produced to cover the National Grid Settlement Metering Upgrade Project (starting in 2013) and for future new metering installations.

The algorithms specified in this document deal with the compensation for errors associated with the measurement circuits external to the meter. The algorithms do not include for the compensation of plant losses (power transformer and/or line losses) where the actual metering point does not coincide with the defined metering point.

National Grid Asset Management (or the National Grid Meter Operator Agent) should be consulted for advice on issues relating to plant loss compensation.

The algorithms will normally be used in a calculation utility (e.g. spreadsheet or similar) which calculates the required errors /compensations for each Metering System (both Main and Check meters) and stores in an associated database the calculated results and relevant source data.

In instances where compensation is not applied to the energy meters (e.g. for very small compensation values) the calculated metering system errors (available from the database) provide part of the evidence that the metering system meets the accuracy requirements of Metering Code of Practice One.

Informative: Metering Code of Practice 1 is an industry standard available on the Elexon web site and with which full compliance is required

The energy meters covered by this document are four quadrant energy meters (combined active and reactive types).