Services		CFTM		Approvals		Electricity		Volume
Sector Review		Authorized Service  Providers		Consumer Page		Natural Gas		Mass

E-24 (rev. 1) Policy on Approval and Use of 2½ Element Metering

Date: 2002-11-29
Bulletin: E-24-E revision 1
Category: Electricity

PDF Format, 19 KB, E-24-E (revision 1)

If you encounter any difficulty in accessing the content on this or any other page please contact us for assistance.

To access any of the PDF documents included in this page, please use this free Adobe Acrobat Reader as needed.

1.0 Scope

This bulletin applies to 2½ element electricity meters used for revenue metering in Canada.

2.0 Background

The 2½ element meters were designed to reduce costs associated with metering, by using one less instrument transformer and associated components internal to the meter. Although 2½ element metering is a legal and approved form of metering used in Canada, there is a potential for error as a result of its noncompliance to Blondel’s theorem when certain conditions of application are not met. This potential for error was considered negligible while presenting significant cost benefits to the electricity utilities. However, the electricity industry and Measurement Canada (MC) have recently questioned this potential error and the appropriateness of using 2½ element metering in light of today’s market and technology.

A national survey was completed by industry representatives of the Canadian Electricity Association and supported by MC to determine the actual impact of 2½ element metering on the Canadian market. The results of that survey¹ were discussed by MC and industry during the Canadian Forum on Trade Measurement 2001 and a number of recommendations were agreed on to reduce the impact of this potential error.

The purpose of this bulletin is to provide policies to reduce the potential for error in the application of 2½ element metering.

3.0 Terminology

Blondel’s Theorem: In a system of N conductors, N-1 meter elements, properly connected, will correctly measure the power or energy taken. The connection must be such that all potential coils have a common tie to the conductor in which there is no current coil.

Self-contained Meter: A meter designed to be connected directly to a power circuit, without the use of external devices such as instrument transformers or shunts.

Transformer Type Meter: A meter designed to be used with instrument transformers.

4.0 Approval Policy

4.1 Applications for approval of self contained 2½ element meters will no longer be accepted by Measurement Canada after December 31, 2002.

4.2 Applications for approval of transformer type 2½ element meters will continue to be accepted by Measurement Canada.

5.0 Installation Policy

5.1 Effective April 1, 2003;

(a) all new, and

(b) all reconstruction of existing,