Preface
This is the third edition of CSA Standard C108.3.1 (now CAN3-C108.3.1), Limits and Measurement Methods of Electromagnetic Noise from AC Power Systems, 0.15 - 30 MHz. It supersedes the second edition published in 1975, entitled Tolerable Limits and Methods of Measurement of Electromagnetic Interference from Alternating Current High Voltage Power Systems 0.15 MHz - 30 MHz, and the first edition published in 1948 under the designation C22.4 No. 103, Tolerable Limits and Special Methods of Measurement of Radio Interference from High Voltage Lines and Apparatus.
Limits of electromagnetic noise from electric power systems have been established in order to maintain electromagnetic compatibility between two public services; the transmission and distribution of electric power and telecommunications and radio broadcasting. This Standard specifies limits and measurement methods for alternating current overhead power lines and stations at distribution and transmission voltages up to 800 kV, and at frequencies between 0.15 and 30 MHz.
Consideration has been given to the practicability of the specified limits from the standpoint of technical practice and economic feasibility. It is considered to be more satisfactory to provide limits for complete power lines and stations rather than to set limits on individual components. In this way, the power utility is free to carry out design and remedial measures where they are most effective.
This third edition incorporates the CISPR type measuring instrument and measurement procedures. These are being adopted in many CSA standards on EMC in order, wherever possible, to harmonize Canadian standards with the recommendations of the International Special Committee on Radio Interference (CISPR), a Committee of the International Electrotechnical Commission. To allow time for changeover to the new instrumentation, this Standard still specifies that the older ANSI type measuring instrument may also be used. Clauses 4.2.2 and 5.1.2 specify the resulting changes in procedures and limits. Appendix C discusses the rationale for these changes. After a period of approximately five years after publication of this edition, the committee proposes to revise the standard calling only for use of the CISPR type instrument.
The concept of relaxed noise limits in large metropolitan areas, which was included in the second edition, has been moved to a nonmandatory appendix in this Edition. This concept may be of vital importance to electric power utilities forces to route power lines through heavily built-up areas. It might, however, be difficult to specify the exact areas in a city where relaxation of limits could be applied. The use of this concept should be considered on an individual basis.
Although this Standard is directed mainly to the AM broadcast band, 535-1605 kHz, the limits should also provide protection to services in the LF and HF bands. A further standard covering the VHF and UHF bands up to 1000 MHz will be prepared when sufficient technical information is available. Similarly, a standard covering dc lines will be prepared in the future.
Five Appendices are attached to this Standard. They are not a mandatory part of the Standard:
A - Relaxed Noise Limits in Large Metropolitan Areas;
B - Radio Influence Voltage Limits for Apparatus, Insulators, and Hardware;
C - Rationale for Different Limits with CISPR and ANSI Type Measuring Instruments;
D - Implications of Acceptable Noise Levels on AM Radio Broadcast Reception; and
E - Interference to VHF Reception - Noise Sources and Means of Prevention.
This Standard represents the voluntary contribution of electric power utilities towards the solution of problems arising from the continuing development of telecommunications services. It was prepared by the CSA Technical Committee on Electromagnetic Compatibility of High Voltage Power Systems under the jurisdiction of the Standards Steering Committee on Electromagnetic Compatibility and was formally approved by these Committees. It has been approved as a National Standard of Canada by the Standards Council of Canada.
Scope
1.1 General
This Standard applies to electromagnetic noise originating from alternating current, overhead electric power lines, and associated generating and distributing stations.
1.2 Equipment Covered
This Standard applies to lines and stations the construction of which was commenced after the date of publication of this Standard.
1.3 Voltage
This Standard applies to power lines and stations operating at voltages up to 800 kV phase to phase.
1.4 Frequency
The limits apply from 0.15 to 30 MHz.
1.5 Weather
The Standard applies during fair weather conditions, as defined in Clause 2. During periods of rain, snow, or fog, noise in excess of the limits stated in Clause 5 may occur.
1.6 Operating Conditions
The Standard applies during normal operating conditions of the power system. During infrequent, abnormal operating conditions outside of the control of the power utility, such as operation at unusually high voltages or use of temporary structures following damage to power line towers, noise in excess of the limits may occur.
