A State-of-the-Art Review on Synchrophasor Applications to Power Network Protection

The demand for electricity supply has been increased many folds over the last few decades. However, the growth in the electric infrastructure has not been increased accordingly due to deregulation of the energy markets, economic and environmental reasons. In present days, power networks are most often operated closer to their stability limit to fulfill the growing electricity demand. As a result, the security and safety of the power system today is at risk. Investigation on large blackouts in the recent past show that maintaining system reliability and integrity becomes more and more difficult due to reduced transmission capacity margins and increased stress on the system. Under the stressed operating condition, the widely-used distance relaying based transmission line protection schemes are susceptible to maloperation. The use of series-compensated and multiterminal lines is another concern for the distance protection scheme. At the same time, the present advancements in the wide-area measurement systems (WAMS) using synchrophasors has shown potential for ensuring improved protection for different power networks operating even at critical conditions. In this paper, the authors first investigate the limitations of existing distance relays while protecting different power networks during stressed operating conditions. Then, an extensive review is made on the application of synchrophasor based WAMS technology for reliable power system protection. The objective of the present study is mainly to bring the attention of the researchers from academic institutions, industries and utility grid on the possible applications of synchrophasors based WAMS technology for ensuring improved protection to today's power system.