Smart meters

Well for the time being WPs domestic users are not half hourly metered, so they do not get charged for poor power factors. Yet.

But even though that is true, some digital power meters that are the basis of the new smart meters are not as good at correcting for power factor due to funny wave-forms, compared to the traditional poor power factor where both the current and voltages are nice sinewaves, just offset in time.

A slightly dated study by some chaps at the University of Twente  highlighted some problems with electronic loads, and digital sampling meters, reporting quite bad over reading compared to the reference spinning disc metering (over  500% in some conditions !).

(Measurements were repeated with more meters and supplied from standard, low internal impedance, mains supply in the laboratory. Deviations of +475%, +566%, +569%, +581%, +582% and -31% and -32% were registered, with again the positive deviation for Rogowski coil current sensors and negative deviations for the Hall sensors.)

The meters used were the 3 phase smart meter kind used in Holland, but there is no reason to assume that UK specific single phase models by the same makers would be so much different internally- they are all tested to the same Euronorms after all.

Mike.

PS Selling power factor correction caps to domestic users is a bit of snake oil, but some low pass filtering on any really spiky loads may be worth while.

Well for the time being WPs domestic users are not half hourly metered, so they do not get charged for poor power factors. Yet.

But even though that is true, some digital power meters that are the basis of the new smart meters are not as good at correcting for power factor due to funny wave-forms, compared to the traditional poor power factor where both the current and voltages are nice sinewaves, just offset in time.

A slightly dated study by some chaps at the University of Twente  highlighted some problems with electronic loads, and digital sampling meters, reporting quite bad over reading compared to the reference spinning disc metering (over  500% in some conditions !).

(Measurements were repeated with more meters and supplied from standard, low internal impedance, mains supply in the laboratory. Deviations of +475%, +566%, +569%, +581%, +582% and -31% and -32% were registered, with again the positive deviation for Rogowski coil current sensors and negative deviations for the Hall sensors.)

The meters used were the 3 phase smart meter kind used in Holland, but there is no reason to assume that UK specific single phase models by the same makers would be so much different internally- they are all tested to the same Euronorms after all.

Mike.

PS Selling power factor correction caps to domestic users is a bit of snake oil, but some low pass filtering on any really spiky loads may be worth while.