Understanding Radio Noise:

Radio noise is the unwanted electromagnetic emission from electrical & electronic devices/systems while operating that can interfere with other radio communication systems.

Radio noise can be emitted during the operation of the power system transmission and distribution facility (overhead lines, substations & associated equipment). The causes of radio noise emission from overhead line infrastructure are:

• Corona discharges in the air at the surfaces of electrical conductors, and hardware. 
• Discharges and sparking at insulator’s highly stressed areas
• Sparking at loose or imperfect contacts, and at defects in hardware (cracks, rust).

Radio noise may also generate from high-voltage apparatus in substations. If the radio noise level at the antennas used for radio reception is too high, it can cause degradation of the quality and performance of the respective radio communication or broadcast service that is in the vicinity of the overhead line/substation infrastructure.

What is CISPR 18?

CISPR 18 series are the technical reports that have three parts, CISPR TR 18-1, CISPR TR 18-2, and CISPR TR 18-3. These technical reports are dealing with radio noise from overhead power lines, distribution lines, substations, and associated equipment which may cause interference to the radio reception.

 Let’s discuss these technical reports one by one.

 Note: that the CISPR 18 series does not deal with biological effects on living matter or any issues related to exposure to electromagnetic fields.

What is CISPR TR 18-1?

CISPR TR 18-1 is a Technical Report and is the first of the CISPR 18 series. It applies to radio noise generated from overhead power lines, distribution lines, substations & associated equipment, which may cause interference to radio reception.  The report covers the frequency range of 0.15 MHz to 3 GHz.

The scope of the CISPR TR 18-1 document contains information in relation to physical phenomena involved in the generation of radio noise from overhead power lines, distribution lines & associated equipment, causes of radio noise, measurement and effects of radio interference, and design aspects in relation to this interference. This part of the CISPR 18 series also features methods and examples for establishing limits and prediction of tolerable levels of interference from high voltage overhead power lines and associated equipment. Currently, the third edition of this technical report (CISPR TR 18-1:2017, published in 2017) is available and valid.

The purpose of the CISPR TR 18-1 report is to provide information on the many factors relating to protecting the reception of radio, especially (but not limited to) analog television and digital terrestrial television broadcasting, from interference due to radio noise generated by AC and DC overhead power lines, distribution lines, and associated equipment.

The CISPR 18-1 report is intended to be a useful aid to overhead line designers and also to anyone concerned with checking the radio noise performance of a line to ensure satisfactory protection of wanted radio signals. The third edition (CISPR TR 18-1:2017) supersedes the second edition published in 2010. The third edition features significant technical changes from the previous edition, which are listed below.  

• Features updation in the description of the RF characteristics of spark discharges which might contain spectral radio noise components up to the GHz frequency range;
• Has the addition of state of the art in HVDC converter technology.

Note: This document does not consider radio frequency interference due to the pantograph of overhead railway traction systems.

Additional information on CISPR TR 18-1:2017:

What is CISPR TR 18-2?

CISPR TR 18-2 is a Technical Report and is the second part of the CISPR 18 series. It applies to radio noise generated from overhead power lines, distribution lines, substations & associated equipment, which may cause interference to radio reception. The report covers the frequency range of 0.15 MHz to 3 GHz. Currently, the third edition of this technical report (CISPR TR 18-2:2017, published in 2017) is available and valid.

The scope of the CISPR TR 18-2 document contains methods of measurements & test procedures for on-site measurement of radio noise in the vicinity of high-voltage (HV) overhead power lines and substations and also contains methods for determination of radio noise limits for protection of radio reception. The purpose of the report is to protect the radio reception (from the radio noise) in the vicinity of high-voltage (HV) overhead power lines and substations. The measurement methods and procedure of this document also used to measure the radio noise generated by line equipment and accessories in a laboratory.  

 The CISPR TR 18-2 report is a useful aid to engineers engaged in the maintenance work of overhead power lines and substations and also to anyone concerned with checking the radio noise performance of a line to ensure satisfactory protection of radio reception.

On-site measurements in the vicinity of HV overhead power lines should be carried out as per the instructions provided in the subclause of this document. The measuring site of HV overhead line should be flat, free from bushes and trees, and remote away from large metal structures and other overhead power and telephone lines.

The third edition (CISPR TR 18-2:2017) supersedes the second edition published in 2010. The third edition is adapted to the modern structure and now also covers an adequate measurement for radiated disturbances from overhead HV power lines and substations in the frequency range of 300 MHz to 3 GHz, since gap-type discharges can be a potential noise source interfering with modern digital radio communication.

It is emphasized that the CISPR TR 18-2 does not specify a single set of limits to be applied internationally. Rather it describes the procedures to enable national authorities to specify limits where it is decided that there is a need for regulations.

Additional information on CISPR TR 18-2:2017:

What is CISPR TR 18-3? 

CISPR TR 18-3 is a Technical Report and is the third part of the CISPR 18 series. It applies to radio noise generated from overhead power lines, distribution lines, substations & associated equipment, which may cause interference to radio reception, excluding the fields from power line carrier signals. The report covers the frequency range of 0.15 MHz to 3 GHz. Currently, the third edition of this technical report (CISPR TR 18-3:2017, published in 2017) is available and valid.

The CISPR TR 18-3 report covers the code of practice to minimize the generation of radio noise from the overhead power lines (HVDC/HVDC) and associated equipment, in order to promote protection of radio reception. The document contains information relating to the design of overhead power lines and associated equipment, preventive & remedial measures, and other related details to minimize the generation of radio noise from the overhead power lines and associated equipment.

This technical report has been prepared to aid engineers involved in the design, erection, and maintenance of overhead lines and HV stations and also to anyone concerned with checking the radio noise performance of a line to ensure acceptable protection of radio reception.

The third edition (CISPR TR 18-3:2017) supersedes the second edition published in 2010. The third edition features significant technical changes from the previous edition, which are listed below.  

• Details related to the localisation system of spark discharges which might contain frequency components up to 3 GHz;
• Details related to equations for predetermination of the radio noise level from HVDC overhead power lines.

Additional information of CISPR TR 18-3:2017: