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Significant photovoltaic (PV) penetration accelerates voltage problems in distribution networks. We have so far studied what kind of low voltage system configurations are desired in the planning stage. In our previous studies, possible equipment measures were classified into several categories, formulating the 'low‐voltage system configuration determination problem'; in addition, a solution algorithm based on the practical priorities of classified measures was proposed. In this study, we propose a more efficient and comprehensive solution method while considering load distribution. Several numerical simulations were conducted to verify the performance of the proposed method. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper proposes a controller for single‐phase synchronous inverters (SSIs) that was designed to stabilize the performance of a grid while providing overcurrent protection during the occurrence of a fault. The proposed controller for an SSI eliminates the multiple feedback control loops consisting of voltage and current controllers under normal conditions to avoid the instability attributed to them. To output the designed voltage precisely calculated using the core circuit, including a swing equation and speed governor, we employ the latched limit strategy for the overcurrent protection, which is combined with a proportional resonance current controller. Numerical simulations and experiments demonstrated that the proposed controller provides the designed performance while ensuring overcurrent protection during normal operation. © 2023 The Authors. IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In recent years, massive introduction of photovoltaic power sources (PV) has compounded the problem of voltage fluctuation in distribution networks. The problem has been recognized from early on, and many research studies have been already reported. However, majority of the previous studies focused on high‐voltage distribution networks. Hence, in this study, the authors investigated appropriate configurations for low‐voltage distribution networks in Japan to address the problem as a planning problem. The on‐site practical measures were examined, and by means of the obtained knowledge, a network configuration problem was formulated for low‐voltage networks. In addition, an effective solution method is proposed, based on the priorities of measures applied to the network equipment. Numerical simulations were conducted for verifying the performance of the proposed method, wherein corroborative results were obtained. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This article presents a novel load frequency control (LFC) method using an adaptive internal model of a power system, where model predictive control (MPC) technique is applied to the internal model, which is being updated on‐line. The proposed method will improve the LFC performance by reducing model identification error and by handling the disturbance effectively. Novelty lies in the combination of MPC and the effective use of the internal model to meet the response time of real world LFC control, which is typically equivalent to generation dispatch control cycle. The effectiveness of the proposed control is confirmed by simulations using a three‐area power system model. The results show that the proposed method can accurately identify the target plant and successfully handle disturbances to realize a reliable LFC. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

The rapid expansion of renewable energy (RE) generation is leading to severe problems related to the reliability of network operation. Power system security is threatened by increased uncertainties of RE outputs and reduced controllable resources. Therefore, it is important to evaluate the robustness of the system controllability in order to preserve system security against uncertainties of RE outputs. We refer to the robustness of the system in this context as 'robust power system security'. This paper proposes a new formulation for evaluating the robust security region in controllable parameter space where the conventional N-1 security criterion suffices in the presence of uncertainties. We specify the confidence interval (CI) of uncertain parameters and obtain the worst case feasible region defined by a set of security constraints, which is a very new approach in the treatment of uncertainties. We use the minimum set of static constraints in the load dispatching problem with CI of RE prediction to evaluate the security region, which is referred to as the robust static security region (RSS) in this paper. The proposed method is useful to assess the degree of difficulty of system planning and operation from the viewpoint of the balance between controllable generator capacity and RE uncertainties. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

High penetration of renewable energy in the future power system will pose a big problem to the load dispatch operation. The large disturbance and high forecast error must be considered when scheduling a limited number of controllable generators to follow rapid change in load. This paper proposes a dynamic economic load dispatch (DELD) problem approach based on the concept of a feasible operation region (FOR). FOR is defined as the region that committed generators may operate in to match the load profile without violating the ramp-rate constraints. The DELD problem is solved in two stages. In the first stage, FOR of each generator is computed using recent real-time forecasted load as well as renewable energy generation. In the second stage, a generation schedule is determined by solving the DELD problem interval by interval while considering ramp-rate constraints and FOR constraints. The method can gives feasible solution for feasible load and specify the amount of compensation required for feasible solution for infeasible load. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]