Tetsuo Otani

A Primary Evaluation for Applicability of IEC 62056 to a Next-Generation Power Grid

We are developing a next-generation power grid in the low-carbon era, which operates and controls demandside equipment as well as that on the power generation and transmission sides. For these operations and controls, a computer unit, called a customer gateway in this paper, exchanges data with devices in customer premises and those in this grid. To ensure interoperability for communications with the customer gateway, a standard protocol such as IEC 62056 could be applied. The applicability of the latter for the customer gateway, however, remains to be ascertained. We specify the requirements for customer gateway communications in this paper. In addition, we show performance results measured using an experimental system with IEC 62056. Based on the requirements and results, we argue that IEC 62056 has no problem with respect to the transfer of data in bulk. In terms of latency, we must develop some methods to shorten the elapsed time and thus fulfill the requirements.

A SCADA System Using Mobile Agents for a Next-Generation Distribution System

We examine a future distribution system capable of solving problems caused by the connection of numerous distributed generators. A supervisory-control-and-data-acquisition (SCADA) system for this distribution system should be economical, flexible, and reliable, and should execute a real-time process. In this paper, we propose a SCADA system using mobile agents for flexibility. In addition, we show two types of communication protocols that make agent migration more fault-tolerant, and perform experiments where the SCADA system executes earth fault protection within the required time. These results indicate that the SCADA system based on our proposed technologies should be capable of fulfilling the real-time processing requirement.

Evolutionary high-dimensional QoS optimization for safety-critical utility communication networks

This paper proposes and evaluates an evolutionary multiobjective optimization algorithm, called EVOLT, which heuristically optimizes quality of service (QoS) parameters in communication networks. EVOLT uses a population of individuals, each of which represents a set of QoS parameters, and evolves the individuals via genetic operators such as crossover, mutation and selection for satisfying given QoS requirements. For evaluating EVOLT in real-world settings that have high-dimensional parameter and optimization objective spaces, this paper focuses on QoS optimization in safety-critical communication networks for electric power utilities. Simulation results show that EVOLT outperforms a well-known existing evolutionary algorithm for multiobjective optimization and efficiently obtains quality QoS parameters with acceptable computational costs. Moreover, EVOLT visualizes obtained QoS parameters in a self-organizing map in order to aid network administrators to intuitively understand the QoS parameters and the tradeoffs among optimization objectives.

A SCADA system using mobile agents for A next-generation distribution system

We examine a future distribution system capable of solving problems caused by the connection of numerous distributed generators. A supervisory-control-and-data-acquisition (SCADA) system for this distribution system should be economical, flexible, and reliable, and should execute a real-time process. In this paper, we propose a SCADA system using mobile agents for flexibility. In addition, we show two types of communication protocols that make agent migration more fault-tolerant, and perform experiments where the SCADA system executes earth fault protection within the required time. These results indicate that the SCADA system based on our proposed technologies should be capable of fulfilling the real-time processing requirement.

Characteristics of AMI using DLMS/COSEM and IEEE 802.15.4g multi-hop wireless communication

IEC 62056 for upper-layer protocols and IEEE 802.15.4g for communication infrastructure are promising means of advanced metering infrastructure (AMI) in Japan. However, since the characteristics of a communication system based on these combined technologies have yet to be identified, this paper gives the communication failure rates and latency acquired by calculations. In addition, the calculation results suggest some adequate AMI configurations, and show its extensibility in consideration of the usage environment.

Application of the IEC 61850 to communication in distribution automation and building energy management systems - Evaluation of the applicability of standard Logical Nodes and Data Objects

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.

Constraint-Based Evolutionary QoS Adaptation for Power Utility Communication Networks

This paper studies an evolutionary multiobjective optimization algorithm, called EVOLT, which heuristically optimizes QoS (quality of service) in communication networks for electric power utilities. EVOLT uses a population of individuals, each of which represents a set of QoS parameters, and evolves them via genetic operators such as crossover and mutation for satisfying given QoS requirements. Simulation results show that EVOLT outperforms a well-known existing evolutionary algorithm for multiobjective optimization and efficiently obtains quality QoS parameters with acceptable computational costs.

XMPP-based energy management system architecture for communications systems

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.

A Proposal of IP-based Computer Network Architecture for Facility Maintenance Information

Abstract – In this paper, we propose IP-based computer network architecture for communications of facility maintenance information. This architecture enables realization of overlay network on the IP network to control the communications. We also examined a feasibility of the architecture with an experiment system. The result shows that the feasibility of the architecture is confirmed. Keywords : Facility maintenance, IP network, Network control, Network management 1. Introduction It is necessary for Japanese electric companies to operate electric apparatus until limit of their performance and life and maintain them with a broad view all over power system. Technologies for condition-based maintenance (CBM) are being researched and developed. It is expected various sensors are allocated in substations and power plants and sensor information is collected across wide area to check electric apparatus, repair them and formulate a maintenance plan in the future. It is effective to realize facility maintenance networks to collect and deliver the information with proof and stability for long time and utilize the information by compiling data in accordance with their usage. The networks are also required to be adaptive to plugging sensors in and out in accordance with secular variation of electric apparatus and collect and deliver their information. Japanese electric companies already have built wide area IP networks to transfer information for their business supporting systems. It is effective for utilizing their existing IP networks as foundation of the facility maintenance networks, which realizes facility maintenance systems. The IP networks enclose information for other application systems including business support systems. Controlling the communications for each application systems has activity on assuring the quality of the communications. It is required for satisfying requirement of the facility maintenance network to build communication control functions for the network. Therefore, Section 2 illustrates the outlines and problems of existing technologies to satisfy the requirements for the facility maintenance network. Section 3 follows by proposing architecture to control communications for facility maintenance information. Section 4, we also examined feasibility of the architecture with an experiment system and the result shows that the feasibility of the architecture is confirmed, before concluding in Section 5.

Application of IEC 61850 to the communication of a large-scale photovoltaic power generation operation - Web service and conformance test -

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.