Using spread-spectrum radio as a cost-effective teleprotection channel - field experience in Mexico

In this paper, we first review the need for communications-based protection of subtransmission lines and show the advantages of directional comparison protection using spread-spectrum radio channels for this application. After a brief description of the applications of directional comparison protection over radio channels in Mexico, we provide data on the field performance of protection schemes and radio channels. We then present cases of protection scheme operation for actual faults. Finally, we provide guidelines for applying directional comparison protection over radio channels to subtransmission lines.