Advanced control and system integrity protection schemes of Croatian power transmission network with integrated renewable energy sources

Liberalization of the electricity market and inevitable control of the electric power system (EPS) on the edge of its stability as a result brings major changes in control and protection technologies. Control and protection systems are becoming increasingly complex, using even more process information and faster communication links. Intelligent electronic devices (IEDs) that perform control and protection functions are also becoming more complex. They are being developed on a daily basis, and just as you install the latest version of the device the newer model becomes available on the market. One of the newer technologies that is also rapidly evolving and can improve control of the EPS at the edges of its stability is the synchronized phasor measurements technology (SPMT). Implementation possibilities of SPMT are wide and they can be classified into three basic groups: system monitoring, control and protection. This paper describes initial phase implementation of an advanced control system of power transmission network around wind farm Vrataruša (42 MW) in the Croatian EPS based on SPMT. Among other things, it also describes guidelines and future use of system integrity protection schemes (SIPS) like adaptive underfrequency load shedding scheme based on real time measurements of loads, system protection against overloading of power transmission lines, system breaker failure protection and system busbar protection.