In large-capacity wind power generation systems, generators need to be made smaller and lighter to reduce equipment costs. In addition, improved maintainability is required to reduce operating costs. Magnetic-geared generators are smaller, lighter, and easier to maintain than conventional generators, so they are expected to be applied to this system. The electrical characteristics of magnetic-geared generators are evaluated using electromagnetic finite element analysis, but because of their complex structure, it was necessary to confirm the design accuracy. Therefore, a verification model of a magnetic-geared generator was produced and several verification tests were carried out. This model was designed as a consequent pole type with a new stator magnet structure that improves magnetic gear torque with a small amount of permanent magnets, taking into consideration structural reliability and ease of manufacture even with a large diameter. In this paper, we confirmed the accuracy of the electrical design using electromagnetic field analysis by comparing with measurement results.

The power sector is being decarbonized to achieve carbon neutrality in 2050, and the G7 has decided to phase out coal-fired power generation by 2035. In this study, we set up coal phase-out scenarios for 2030, 2040, and 2050, and conducted a simulation analysis by unit commitment with an expanded introduction of renewable energy. The simulation results showed that phasing out coal-fired power plants can help reduce CO₂ emissions, and the introduction of coal-fired power plants with CCS was also effective in reducing emissions. On the other hand, it was found that achieving stable electricity supply would be difficult due to the need for renewable energy output curtailment and insufficient adjustment capacity.

To archive Carbon Neutrality by 2050, Japanese government progresses more and more penetration of Renewable Energy Sources (RES) such as Photovoltaics and Wind Turbine. But there are concerns in operating power system with high penetration of RES. Shortage of thermal capacity of transmission limits expanding capacity of RES. Recently, N-1 generation control is expected as a solution of shortage of thermal capacity without constructing new transmission lines. Using N-1 generation control in N-1 contingency, overload of transmission is relieved and more capacity of RES is penetrated to power system. Above background, in this paper, we propose demand and supply control method using Battery Energy Storage System in N-1 generation control to penetrate more capacity of RES. In our proposed method, active power output of generators and BESS are determined by solving Optimal Power Flow (OPF) calculation after N-1 generation control. And determination method of setting point of BESS is proposed to penetrate more capacity of RES. Our proposed method tested in IEEE RTS 24 model and effectiveness of proposed method is shown through simulation case study.

There are several current electricity markets in Japan and the timing of market applications, bids and successes is defined chronologically. In addition, when the aggregator operates the consumer-side resources for the market, the operation plan must be compatible with the customer-side energy management system (ESM). Therefore, aggregators participating in the market need to develop an optimal bidding strategy for multiple markets, considering the characteristics of heterogeneous power resources, the amount of electricity supplied to consumers and imbalance costs. Therefore, this study proposes a market bidding strategy method based on an optimal operation plan for DERs that balances electricity supply to consumers and market participation, targeting the spot market (kWh value) and the balancing market RR-FIT (ΔkW value). The results of bidding simulations based on actual market data for 2023 in Japan show the effectiveness of the proposed method by quantitatively evaluating the combined market value of participating in the spot market in addition to the balancing market, the synergistic effects of combining storage batteries with CGS and integrated value of the business formation of supplying electricity to consumers and the aggregation business from economic indicators such as market profit and imbalance cost.

There is concern that a reduction in power system inertia could lead to a reduction in frequency stability. In order to maintain frequency stability, it is important to estimate the area inertia. In this paper, we propose a method for estimating the area inertia using ambient measurement data of tie-line power flow and frequency measured by PMUs, etc. In the proposed method, the area inertia is estimated from the ambient measurement data based on spectrum analysis. Also, it is verified the effectiveness of the method by simulations using the IEEJ WEST 30-machine system model.

When a constraint violation occurs due to installing a new load in a distribution system, it can be resolved by reconfiguring the distribution system. This involves changing the states of manual and remote switches to satisfy the constraints by improving voltage and current profiles in normal and faulted conditions. However, simple reconfiguration may be insufficient to address severe constraints caused by the new large load installation because power supply restoration to outage sections from healthy sections by closing remote switches when a fault occurs may become infeasible in such cases. To effectively address these severe constraints, it becomes necessary to replace manual switches on tie lines with remote switches, enabling power supply restoration by controlling remote switches. For this purpose, this paper proposes a mixed-integer linear programming (MILP) model that optimally and efficiently determines which remote switches should be replaced with manual ones while satisfying the severe constraints. The model aims to suppress the constraint violations, balance the number of sections, equalize the load capacities across sections, and minimize the number of switch replacements between remote and manual switches. The effectiveness of the proposed MILP model is demonstrated through case studies using a large-scale distribution system model with numerous manual and remote switches.