Shinya Naoi

Power fluctuation suppression system for large scale PV

The large scale photovoltaic (PV) generation station is expected to spread in the future. However, output power of renewable energy sources such as PV is affected by weather conditions and their output tends to be unstable. As a result, the penetration of PV power station makes it difficult to maintain frequency of power system in allowable range. The authors have developed a suppression system to stabilize output power fluctuation of a large scale PV generation station. To reduce short term fluctuation, storage batteries applying SCiBTM are used. In this paper, verification test results are explained and simulation results to improve control performance are also shown.

Study of modeling method of distributed generators considering partial dropout for trunk transmission system

Simultaneous dropout of a large amount of distributed generators caused by a fault in a power line with voltage drop and/or phase change may worsen power stability of a trunk power system. A reduced model of distributed generators in secondary systems considering partial dropout is proposed for the stability analyses. To verify the reduced model, a detailed model and the proposed reduced model are compared under same conditions for a variety of load and fault conditions. For an example of practical applications, a relative comparison of power stability in IEE of Japan EAST 10 machine system model under fault ride through (FRT) requirements is demonstrated.

Demand and supply simulations considering detailed forecast, scheduling and control functions for Japanese Power System with a massive integration of renewable energy sources

A demand and supply simulator is developed to evaluate the effectiveness of various countermeasures against the balancing problems caused by the large integration of variable renewable energy sources (VRES). In our study, photovoltaic and wind power generation output pattern is modeled based on the actual data obtained at physical sites and forecast data from Japanese Meteorological Agency (JMA), to realistically reflect their fluctuation characteristics. One of the benefits of our digital simulator is that it reflects the typical Japanese central dispatching control centers methodologies including week-ahead, day-ahead, and hour-ahead scheduling process based on the latest forecast data available on each time horizon. Above all, not only PV output curtailment but also demand shifting and utilization of battery storages are taken into consideration. In conclusion, PV output curtailment is found to be the most cost-effective in many cases, still there is a room for batteries to be economical when CO2 emission cost spikes.