Approximately 100 years ago, the backbone of protection technology consisted of electromechanical relays. These devices operated based on fundamental principles of physics, utilizing changes in springs and coils induced by variations in current or voltage to perform their functions. Although impressive for their time, electromechanical relays had notable limitations: each relay was sizable and typically dedicated to a single protection function.
Today, the landscape has dramatically evolved with the advent of microprocessor-based relays. These modern devices have replaced approximately 100 electromechanical relays with just 50 microprocessor-based ones. They are multifunctional marvels, capable of converting analog signals to digital, performing complex mathematical calculations like fast Fourier transforms, detecting various types of faults, and controlling circuit breakers.
Furthermore, microprocessor-based relays come with enhanced communication and networking capabilities, supporting everything from serial communications to TCP/IP Ethernet, and even enabling transfer tripping. This advancement has significantly improved the efficiency and reliability of protection systems.
Today, we see the emergence of centralized protection and control systems, often referred to as digital substations using such technologies as IEC 61850. This technology continues to reduce the physical footprint of protection systems. Looking ahead, what requires extensive hardware will be managed by one or two servers, such as Dell blade servers, fitting into a compact form factor. This reduction in physical wiring complexity shifts the complexity to software programming, making systems physically more streamlined, manageable, and at the end of the day cheaper.
The evolution from electromechanical relays to microprocessor-based relays and now to centralized systems marks significant progress. Initially, these systems had no remote control capabilities. Now, network-based relays can communicate seamlessly with switches, remote terminal units (RTUs), and SCADA systems, all secured by robust firewalls and intrusion detection systems.
Today’s advanced systems monitor current and power through instrumentation transformers, feeding data into merging units that connect to centralized protection systems. These setups offer remote operators extensive visibility and are nearly plug-and-play, simplifying installation and maintenance.
As we look to the future, the concept of cloud-based protection and control is on the horizon. This raises intriguing questions, particularly regarding time-sensitive requirements. How will these be managed in a cloud-based environment? We will explore these considerations in a future discussion.
Over the past century, we have transitioned from the robust but bulky electromechanical relays to the sleek, efficient, and highly capable digital systems of today. The journey of protection and control technology continues to evolve, promising even more exciting advancements in the years to come.
About the Author:
Dr Nathan Wallace, PE has BS degrees in Electrical Engineering, and Physics, a MS in Engineering, and a Ph.D. in Engineering from Louisiana Tech University. Nathan is a CoFounder and Director of GridIntel. Nathan is actively involved in the IEEE-PES PSRC and PSCC technical committees and currently chairs two IEEE standards development working groups. Nathan is a licensed PE in AL, LA, MS, OH, and TN.