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This paper investigates the control method under the 30-min balancing rule for grid-connected PV power. It is possible to adjust the noticed power for PV supply before two hours. The noticed power, that is the adjusted PV supply, and the measured power are controlled under the 30-min balancing rule using a battery, and the 30-min control section is divided.

As the key solution for energy sustainability this decade, the growth of installing photovoltaic (PV) systems has dramatically increased. However, the high penetration of PV systems can cause a voltage variation problem in a distribution grid. This paper proposes a model for evaluating the maximum potential for installing PV systems in an urban area under a bus voltage constraint. A PV system is considered as an energy system alternative that replaces a conventional system. Regarding the power variation, it is necessary to add a parameter that is used to evaluate the variation of PV systems in terms of a standard deviation to the PV systems' electric load curve. The installations of PV and conventional systems are determined as share solutions for each load area along a distribution network. Total power loads and variations in each load area are input to a load flow calculation to obtain each bus voltage and confirm the voltage constraint. Finally, the total PV system installations over the whole network area is maximized. The alternative PV system with battery installation is introduced to validate the model evaluation when comparing with a typical PV system without a battery, which has larger power variation. Furthermore, adjusting the sending voltage at a substation to increase the PV installation is validated using the proposed model. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

In this paper a method to stabilize total output of PV systems by controlling on/off of each PV system is proposed. In the proposed method, the total output of PV systems is controlled so as to fit the output target value by determining off status of each PV system at each time interval when the amount of total power generation exceeds the output target value. Based on measured output of each PV system in instantaneos value, on/off status of each PV system is determined taking into account delay time of control. In order to check the validity of the proposed stabilization control method, the numerical simulations are carried out for a 100PV systems model. The effect of output fluctuation reduction is verified by changing the delay time of control. Furthermore, the utilization ratio and 30 minutes output deviation of PV systems are evaluated for various output target value.

Generators and power storages for communication facilities for emergency use could get involved in realizing smart grids. Standard protocols of OpenADR 2.0b and IEC 61850 are used for communication to ensure the interoperability of smart grid. XMPP (Extensible Messaging and Presence Protocol) has promise to be applied to the transport layer of both of the standard protocols. In this paper, the authors examine the construction of a common communication platform based on XMPP.

To realize smart grid technologies such as load control, load leveling and demand response and solve problems caused by connecting many DERs to a distribution network, a distribution automation system (DAS) and energy management system (EMS) are respectively essential components. The communication of these systems has generally been handled by proprietary or vendor-specific protocols to date. Conversely, in intra- and inter-substation communication, the IEC 61850 has started to gain acceptance in supervisory control communication, due to its interoperability supporting multi-vendor environments. If the IEC 61850 can be applied to communications in DAS and EMS, this is expected to reduce the maintenance and equipment costs of each system. To do so, we must first evaluate the applicability of the IEC 61850 from the perspective of Logical Nodes (LN) and Data Objects (DO), which are data models defined in IEC 61850. This paper focuses on the DAS and building EMS (BEMS) and provides the evolution. We choose BEMSs because we expect many EMSs to be installed in homes or buildings in the near future and anticipate that building energy management functions will include home energy management functions. This evaluation result shows that most data items appearing on such communications can be represented as standard LNs and DOs but several data items cannot be easily represented as the same.

We developed a SCADA server as a prototype to evaluate the applicability of IEC 61850 for the operation of large-scale photovoltaic (PV) generation systems. IEC 61850 and Web-service technology (IEC 61400-25-4) are applied to the data model and the server communication protocol. We also developed a test client for the conformance test, which was then executed. The result showed that the server conformed to IEC 61850 on the data model and protocol. Therefore, the applicability of IEC 61850 to the operation of a large-scale photovoltaic (PV) generation system is confirmed.

A power and heat interchange system with fuel cells in collective housings is proposed. A solution method for determining optimal FC operation plan is proposed. From numerical simulations it is confirmed that fuel cells are effectively used by interchanging power and heat in a collective housing.