Abstract
Recently, many renewable energy sources are connected to power systems. Renewable energy sources such as PV and wind connected to power systems via inverters are called inverter sources. When the percentage of inverter sources increases, the percentage of synchronous generators such as hydro, thermal and nuclear decreases. When many inverter sources are connected to power systems with small capacity which are not synchronously connected to other power systems, the percentage of synchronous generators significantly decreases. Therefore, influences of power system characteristics such as synchronizing power decrease, power system inertia decrease and short circuit capacity decrease are concerned. And influences of power system stability such as transient stability decrease, frequency and voltage fluctuation increase and distortion level increase are also concerned. Previously, power system inertia estimation and power system stability monitoring were done by off-line. Therefore, on-line power system inertia estimation and power system stability monitoring system is newly developed for the purpose of precise understandings of Japanese Eastern (50Hz) and Western (60Hz) power systems.
