Apply Radios to Improve the Operation of Electrical Protection

A few decades ago, power system communications were power-line carrier, leased telephone lines, or pilot wires— all with expensive terminal equipment. Later, electric utilities applied sophisticated microwave communications systems, and optical fiber in optical ground wire (OPGW) was deployed along many transmission lines. More recently, radio has entered into teleprotection applications. This paper discusses fundamental concepts of radio systems and considers them in terms of the control and protection requirements for modern power systems. In many situations, radio solutions are an economical and reliable way to improve the speed and sensitivity of transmission and distribution systems. Further, radio solutions economically integrate distributed generation into power control systems at virtually any point. This paper begins with first principles and concludes with the economic benefits of radio-based control solutions. It considers system parameters for protection using radio solutions and discusses where, when, and how to apply radio as a protection communications method. The paper describes licensed and unlicensed radio principles, spread-spectrum techniques, and data requirements for high-speed protection. Finally, it examines the economic benefits of extending high-speed protection into subtransmission and distribution systems.