Transmission capacity improvement by power system enhancement measures

In Japan, various power system technologies have been advanced. For power system stability and transmission capacity improvement in the future interconnected systems, power electronics technologies are expected to be utilized. Joint research to ascertain effectiveness of power electronic devices has been conducted by The Central Research Institute of Electric Power Industry (CRIEPI) and Japan´s 10 power utility companies. First, a static VAr compensator composed of a self-commutated converter (STATCOM), a thyristor controlled series compensator (TCSC) and a unified power flow controller (UPFC) were selected through evaluation by digital simulations on model power systems. Second, miniature models were developed. The control and protection systems of the equipment were real and could be used practically and immediately. Finally, the effectiveness and the realization-possibility of such power system enhancement measures were verified through analogue simulation studies with actual controllers