Survey results are outlined on big data in electric energy field and their utilization. Large amount of data are being measured, stored, analyzed and utilized in many fields. Electrical energy field is no exception. The survey was conducted from 2014 to 2017 by Investigating R&D Committee for Big Data in Energy Industry and their Utilization Techniques, IEEJ. In this article, which is the first in a series of four related articles, `big data' in this field is characterized and defined, and summary of the survey results are given on existing data and their utilization in diagnosis and anomaly detection, energy supply/consumption planning and control, and emerging services.

This paper overviews processing and analysis for electric energy data. In data processing, after processing of missing data and outliers is briefly described, data integration and production of features are reviewed. Moreover, this paper outlines statistics and machine learning by data analysis of smart meter data as an illustration. Some notes about systemization of processing and analysis functions are also presented.

Investigating R&D committee on energy-related big data and their applications published the technical report about their investigating results. Energy-related big data is defined by 3V (volume, variety and velocity), and detailed results of investigating activities of the committee are described in this report. In this article, the author shows the outlines of energy-related big data applications in electrical power systems, power generation plants, renewable energy using power generations and electrical installations of customers.

The author summarizes application examples of big data in electric energy field for operation and planning of electric power systems. These applications were selected from survey results of Investigating R&D Committee on Energy-Related Big Data and their Applications, IEEJ, from October 2014 to September 2017.

A power system with a massive PV penetration may require many conventional generating units to be disconnected in order to maintain supply-demand balance. In this situation, it may be difficult to sustain power system stability in case a system disturbance occurs. In this paper, as a countermeasure, the prototype Virtual Synchronous Generator (VSG) is developed and its effectiveness is checked experimentally using an analog simulator.

This paper proposes a new optimal network decomposition method with Discrete Parallel Predator-Prey Brain Storm Optimization (DPPPBSO) for Voltage and Reactive Power Control (VQC) in power systems. Recently, parallel or distributed control is required for complicated power systems. To achieve that, power network decomposition plays a key role to improve VQC. The problem formulation may be expressed as one of combinatorial problems. However, it is difficult to solve them due to the NP-hard problem. In this paper, DPPPBSO is proposed to evaluate better solutions with a couple of strategies of the island model for parallel computation and discretization of solutions through the sigmoid function into PPBSO. The proposed method is successfully applied to the IEEE 57-bus system.

Special facilities such as data centers, computer centers, and hospitals with operating rooms require an extremely static electromagnetic environment. In this study, we investigated the effectiveness of an isolated type down-conductor for reduction of the magnetic field inside the building due to lightning strikes by using electromagnetic field analysis. We analyzed the four cases of the down-conductors such as building structures, bare wires, and two types of high-voltage insulated-cables which is sheath opened type and sheath shorted type. Using bare wires and sheath opened cable-type down-conductors, the internal magnetic field of the building reduced. This is because the lightning current flows in the opposite direction in the building structural pillars close to the down-conductors, and it cancel the internal magnetic fields. Comparing the bear conductor and the sheath opened cable-type conductor from the viewpoint of the overvoltage to the building structure, the overvoltage became smaller as the cace of using the cable-type duwn-conductor.

Recent increase of variable renewable energy sources such as photovoltaics and wind turbines makes balancing power supply and demand difficult. One of the methods to support balancing supply and demand in power grid is demand response. In this research, demand response by use of heat pump water heater (HPWH) in spa facility was considered. To predict power consumption of HPWH, HPWH was modeled using real operation data. Hot water demand model was also made using real operation data to predict hot water consumption and avoid hot water shortage. Using both HPWH and demand model, daily operation schedule which satisfies both demand response requirement and spa users' convenience. Demand response experiment was conducted to evaluate demand control error and effect on users' convenience. From the result, daily operation schedules were generated and HPWHs were operated without water shortage. However, power consumption errors occurred due to HPWH model error, water demand error, input ambient temperature error and reheat operation. In the future, power consumption errors will be reduced to increase accuracy of input ambient temperature and consider tank heat loss into operation schedule.

The authors have evaluated the possibility of deterioration diagnosis of Oil-filled (OF) cable systems by PD measurement so far. In our previous studies, we confirmed continuous occurrence of PDs even under the design electric field of 275kV OF cables. However, correlation between PD characteristics and internal conditions of the oil gap defect was not obtained. Therefore, in this study, we experimentally investigated the effects of the switching impulse voltage superimposition that can occur in practical operation of 275 OF cable systems on PD characteristics and we observed the conditions inside the oil gap defect by a CCD camera.

This letter presents a consideration on Virtual Synchronous Generator (VSG) control of power system, in which an interpretation of each component of the VSG control, i.e., virtual inertia, virtual damping, and virtual synchronizing power, is developed based on the sustained oscillation theory. Finally the consideration is applied to the HVDC interconnection line power flow control to enhance the transient stability of power system including large wind farm.