Japan's control system equipped with more advanced monitoring, control and operation support functions - For the change of the energy supply structures in the future

For the realization of the low-carbon society, the integration of renewable energy sources is expected to increase in the future, resulting in more and more complex operation of the power system. At present, control systems in Japan do not equip functions which are intended to cope with this directly, but for its advanced functions, these systems have enough potential to be applied to cope with the challenges and support the operators, after the complexity of the power system operation had increased in the future. This paper presents the specifications and functions of advanced monitoring and control systems introduced at some of the utilities in Japan, from the perspectives of monitoring, control, operation support and maintenance. As for the monitoring function, an online reliability monitoring function is presented. The online reliability monitoring function in the EMS/SCADA system is equipped with the contingency analysis and reliability calculations based on static and transient stability simulations. As for the control function, a coordinated VQC (Voltage Reactive Power (Q) Control) control system is described. The most suitable voltage profile is produced by OPF (Optimal Power Flow calculation) for the forecasted power grid state generated by using load forecasting and state estimation functions. Using these functions, even in the situation that the distribution of power flow and the voltage profile of the trunk power system changes unexpectedly, an adequate reliability monitoring and voltage control could be realized, based on online monitoring. As for the operation support function, an automatic generation of switching order flowchart and validity check function is introduced. Also as for the maintenance function, a system is integrated into the EMS/SCADA functions of the CLDC (Central Load Dispatching Center) and the TNCC (Trunk Network Control Center) which are separately located, connected via WAN. As a result it had succeeded in facilitating the database maintenance. In Japan, the described functions are in practice at some utilities. By applying these functions, it is expected that we could cope with various challenges, contributing to secure the operation of power systems, as well as to reduce the burden of operators or to prevent operation mistakes.