Category: Electricity
Specification: S-E-09
Document(s): S-E-07 and LMB-EG-07
Issue Date: 2010-04-27
Effective Date: 2010-04-27
Table of Contents
- 1.0 Scope
- 2.0 Authority
- 3.0 References
- 4.0 Definitions
- 5.0 General Requirements
- 6.0 Ratings
- 7.0 Rated Burden
- 8.0 Accuracy
- 9.0 Additional Information
1.0 Scope
This specification applies to 80 milliampere (mA) Current Transformers (CT) and 100 milliampere (mA) Current Transformers (CT) which are intended to be used in revenue metering.
2.0 Authority
This specification is issued pursuant to subsection 12 (1) of the Electricity and Gas Inspection Regulations.
3.0 References
- Electricity and Gas Inspection Act (R.S. 1985, c. E-4), ss. 9(4).
- Electricity and Gas Inspection Regulations (SOR/86-13), ss. 12(1).
- Measurement Canada, LMB-EG-07: Specifications for the Approval of Type of Electricity Meters, Instrument Transformers, and Auxiliary Devices.
- Measurement Canada, S-E-07: Specifications for the Approval of Measuring Instrument Transformers.
- IEEE Std C57.13-2008: IEEE Standard Requirements for Instruments Transformers.
- CAN-CSA 60044-X:07 series: Instrument Transformers series.
4.0 Definitions
Applicable definitions can be found in Measurement Canada (MC) S-E-07.
5.0 General Requirements
All requirements specified in MC specifications S-E-07 shall be applicable to the 80 mA and 100 mA class CT in addition to the following requirements.
6.0 Ratings
6.1 Current rating of 80 mA class measuring CT shall be according to the values in Table 1 below.
Primary Current (A) | Secondary Current (mA) | Ratio |
---|---|---|
5 | 80 | 62.5:1 |
100 | 80 | 1250:1 |
200 | 80 | 2500:1 |
400 | 80 | 5000:1 |
6.2 Current rating of 100 mA class measuring CT shall be according to the values in Table 2 below.
Primary Current (A) | Secondary Current (mA) | Ratio |
---|---|---|
5 | 100 | 50:1 |
100 | 100 | 1000:1 |
200 | 100 | 2000:1 |
400 | 100 | 4000:1 |
600 | 100 | 6000:1 |
800 | 100 | 8000:1 |
7.0 Rated Burden
7.1 Standard burdens for 80 mA class CT shall be according to the values in Table 3 below.
Standard Burden | Characteristics | Characteristics for 60 Hz 0.08A Secondary Current | |||
---|---|---|---|---|---|
Resistance (ohm) | Inductance (mH) | Impedance (ohm) | V*A | PF | |
B0.005 | 17.6 | 23 | 20 | 0.125 | 0.9 |
B0.01 | 35.2 | 45 | 39 | 0.25 | 0.9 |
B0.03 | 105.5 | 135 | 117 | 0.75 | 0.9 |
B0.05 | 176 | 226 | 195 | 1.25 | 0.9 |
7.2 Standard burdens for 100 mA class CT shall be according to the values in Table 4 below.
Standard Burden | Characteristics | Characteristics for 60 Hz 0.1A Secondary Current | |||
---|---|---|---|---|---|
Resistance (ohm) | Inductance (mH) | Impedance (ohm) | V*A | PF | |
B0.005 | 11.3 | 14 | 13 | 0.125 | 0.9 |
B0.01 | 22.5 | 29 | 25 | 0.25 | 0.9 |
B0.03 | 67.5 | 87 | 75 | 0.75 | 0.9 |
B0.05 | 112.5 | 145 | 125 | 1.25 | 0.9 |
8.0 Accuracy
8.1 Assignment of Accuracy Class - A measuring mA current transformer shall be given an accuracy class as specified in Table 5 for each standard burden, (Tables 3 and 4), up to the maximum for which it is designed.
8.2 Basis for Measurement Accuracy Classes - Accuracy classes for mA measuring CT are based on the requirement that the transformer correction factor (TCF) shall be within specified limits for the following conditions:
- 100% of rated primary current or the corresponding continuous current factor
- 10% or 5% of rated primary current
- Power factor (lagging) of metered power load from 0.6 to 1.0
- Burden of a specific standard value
- Normal service conditions
Note: At 5% or 10% of rated primary current, the permissible error is twice the error at 100% rated primary current.
The relationships between the limits of the ratio correction factors (RCFs) and the phase angle for the limiting values of the TCFs specified in Table 5 are shown in the parallelograms in Figure 1.
Accuracy Class | 100% rated current* | 10% rated Current | 5% rated current | Limits of power factor (lag) of metered power load |
---|---|---|---|---|
0.15 | 0.9985–1.0015 | - | 0.997–1.003 | 0.6–1 |
0.3 | 0.997–1.003 | 0.994–1.006 | - | 0.6–1 |
0.6 | 0.994–1.006 | 0.988–1.012 | - | 0.6–1 |
Note:
- These limits also shall be applicable at the maximum continuous current rating factor (RF)
- 5A:80mA 5A:100mA rating CT shall not be approved for accuracy class other than 0.15%
Figure 1–Limits for measuring current transformer
Limits of 0.15 accuracy class
Limits of 0.3 accuracy class
Limits of 0.6 accuracy class
9.0 Additional Information
For additional information regarding this specification, please contact the Senior Program Officer responsible for electricity measurement.
Alan E. Johnston
President