Inspire the Next Case study Making Polish power grid more resilient High-end solution in compliance with the Polish national power grid code regarding permitted harmonics at 110 kV Customer challenge The Polish Power Grid Company, PSE experienced disturbances in power distribution during the particularly hot summer of 2007. High consumption, partly related to air conditioning use, led to shortages in the northern part of the country. To strengthen the grid, the decision was made to install filters at the 110 kV level. This project was the first filter installation for PSE at 110 kV. The goal of the installation was to relieve the load on the distribution line, raise the voltage and minimize losses in the network. Hitachi Energy solution Hitachi Energy quoted and installed three band-pass filters in the Wloclawek, Torun and Narew substations. The filters were tuned to the 5th harmonic so as to reduce the harmonic to this level. Each filter produces 50 Mvar at 110 kV. The main task of the Hitachi Energy filter solution is to provide reactive power. This stabilizes the grid and also fulfills the requirement for allowed distortion levels at 110 kV. This was a turnkey delivery and included other Hitachi Energy equipment, such as circuit breakers, Switchsync™ controllers, VTs/CTs and surge arresters from Hitachi Energy plants in Sweden and Poland. The three filters are in operation, doing the job they were intended for - strengthening the Polish power grid. The PSE contract stipulated that measurements at each connection point of the grid were to be made before finalization of the solution. These measurements were made by Hitachi Energy. In-depth analyses of the measurements made by Hitachi Energy showed that there could be a problem in connecting a filter with a true BP configuration at one of the substations. This substation is situated at the end of a transmission line, and resonance could occur between the grid and the filter at this point. The final solution was due to the analyses modified from the first suggestion by Hitachi Energy, and a resistive element was added into the filter circuit. The filter became a damped one, which minimized the risk for resonance with the net. Country Customer PSE net Location of project Scope of delivery Year of delivery Engineering and construction of installation Poland Polish Power Grid Company (PSE Operator S.A.) 750 / 400 / 220 / 110 kV Wloclawek, Torun and Narew 3 units, band-pass filters 2009 Hitachi Energy Poland Sp. z o.o. ^Hitachi Energy

01 The filters installed and energized during 2009. Customer benefits • A solution that took consideration to the actual situation in the grid and eliminated grid resonance • Optimized filter components for a small installation footprint • Execution of a complete, tailor-made, turnkey project • Short design and delivery times We have delivered filter components, shunt- and series-compensating gear and HVDC and FACTS transmission systems to power companies and industries all over the world. A complete program with comprehensive support Hitachi Energy in Sweden has more than 70 years of experience...