Cover Story

Protection Considerations for Interconnecting Solar Generation to the Transmission System

Solar generation in the state of Georgia is growing rapidly both on transmission and distribution networks. In 2015, approximately 240 MWs of solar generation came online connected directly to the transmission network. By the end of 2016, another 600 MWs of transmission connected solar generation is expected to come online.
Generation capacity, per development, varies from 20MWs connected at sub-transmission voltage on a radial system to 140 MWs interconnecting to 230kV networked transmission system.  Geographically, all solar generation sites are located south of the line from Columbus, Macon and Augusta.
The largest cluster is located in the Taylor County between the cities of Columbus and Macon with approximately 400 MWs of solar generation. Inverter based solar generation is very different from traditional synchronous machine based generation. A conventional synchronous generator typically produces 6-8 times rated load current during faults for several cycles.
Inverter based solar generation produces 100-120% of rated current during faults for a very short time. Application of protection schemes to interconnect solar generation requires special consideration. More

Power. Flexible. Easergy.
BeijingSifang June 2016