Following the breakup of the Soviet Union, the Georgian power grid became isolated and vulnerable. After nearly two decades of frequent blackouts caused by decaying Soviet-era equipment, it was in dire need of modernization.
The recurring blackouts took their toll on Georgia, hindering industrial production, impacting critical services, and shortening the lifespan of power system equipment. In 2010 alone, Georgia sustained six major system blackouts, prompting the nation to seek an immediate solution.
At the heart of the problem was the stress and overheating of “The Backbone,” a 500 kV single-line transmission system that carried energy from the Enguri hydropower plant in western Georgia, across the Caucasus Mountains, to the densely populated regions in the east. When this 500 kV line tripped off, it caused ripple effects through neighboring lines, eventually causing parallel transmission lines to go down. The severe imbalance of generation and load that resulted often led to a nationwide blackout.
The nation’s electric utility, Georgian State Electrosystem (GSE), needed a solution to avoid blackouts—one that would detect a fault, generate a load-shedding decision, and trip the circuit breaker, all in less than 100 milliseconds.
In addition, the new system had to be implemented quickly. The heat of summer was only four months away and would bring with it a higher potential for blackouts.
The blackouts had been going on for 20 years. The situation in the last 10 to 15 years in Georgia’s energy grid was very difficult.
GSE partnered with SEL to develop a country-wide emergency control system (ECS) to keep the power system stable. SEL exceeded GSE’s requirements by designing an ECS that can react to a power system event in less than 12 milliseconds. The GSE and SEL team specified, designed, built, tested, and installed the entire system in under four months.
The ECS solution includes decision-making SEL relays at the most critical transmission line substations. These relays constantly monitor the transmission lines, check for faults, and quickly shed loads if a fault occurs. This prevents overload in other areas of the power system to maintain stability and prevent blackouts.
The effectiveness of the new ECS was proven in the summer of 2011 when, in a two-week period, it was called upon five times to shed loads at 500 kV substations along The Backbone. The SEL system worked as designed, protecting the country from blackouts and ushering in a new era of reliable energy for the Republic of Georgia.
GSE has continued to work with SEL to improve reliability ever since. Following the initial ECS success, GSE asked SEL to help create a remedial action scheme (RAS) to further improve reliability, system management, and fault recovery. Soon after, GSE called on SEL again to modernize the protection, control, monitoring, and communications systems for ten GSE substations. This modernization greatly improved the capabilities and resilience of the substations. In addition, the SEL design and construction methods enabled the project to be completed in just two years—half of the alloted time.
One step at a time, GSE’s efforts are paying off, and life is looking much brighter in Georgia.