PS-E-08-E—Provisional specifications for the installation and use of 2-element electricity meters
Table of contents
- 1.0 Scope
- 2.0 Background
- 3.0 Authority
- 4.0 Terminology
- 5.0 Metering configuration
- 6.0 Electrical requirements
These specifications apply to 2-element electricity meters used to measure volt-ampere (VA) or volt-ampere hour VA·h on 3-phase 4-wire installations which have been installed using a delta connection at the terminal (test) block.
Measurement Canada has never allowed the use of a 2-element, rectithermal VA meter in the above configuration, as the resulting registration is too high by approximately 25%. In 1999, at the pre-Canadian Forum on Trade Measurement, Measurement Canada raised concerns that 2-element, electronic meters, programmed to measure arithmetic apparent power (VA) used in a similar configuration, will measure VA with errors comparable to those found with the electro-mechanical equivalent.
These specifications are issued under the authority of section 12(2) of the Electricity and Gas Inspection Regulations.
- Delta connection
The wiring configuration of a 3-phase 4-wire metering installation which sums the secondaries of the current instrument transformers. The configuration is made in such a way to add the Ib current to the Ia and Ic secondaries of the instrument transformers. The resultant current measured by the meter is Iab in one element and Icb in the other element.
- Test Block
The wiring termination point for the secondaries of the voltage and current transformers. It is the connection point where measurement test equipment can be connected for inspection purposes.
5.0 Metering configuration
Standard drawing number 3409 below shows the acceptable configuration for the use of a 2-element meter to measure a 3-phase 4-wire electrical metering installation using voltage and current instrument transformers.
6.0 Electrical requirements
For 2-element meters used in the installation configuration shown in section 5 it shall be assured that:
- in the case of an electro-mechanical demand meter it does not provide full rectification of the voltage and current inputs,
- in the case of an electronic demand meter it is of the type that calculates VA using vectorial VA calculations and not arithmetic VA calculations
- the paralleled current flowing in each current circuit never exceeds the maximum current rating of the meter.
- Date modified: