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DC system has the potential of vast and rapid fault current generation due to multiple (line and converters) discharge capacitors and small impedance of DC lines. DC fault current spreads through the system exponentially compared to AC. Such an unexpected huge current causes a voltage drop, impacts the normal operation of system components and exposes the system to a great challenge for fault detection and interruption. For prevention of system destruction during the fault, multiple approaches such as application of Mechanical Circuit Breakers (MCBs), fuses, Solid State Circuit Breaker (SSCB), and Hybrid Solid-State Circuit Breaker (HSSCB) have been proposed and applied. In DC fault applications, fast fault detection and interruption without any interference to the other components are quite important. Therefore, semiconductor breakers have been implemented to meet the DC fault protection requirements with a high-speed operation where traditional MBs have failed. Due to the high conduction loss and low efficiency of semiconductor switches, for fast and efficient DC fault interruption, different Fault Current Limiter (FCL) types are suggested. Although a high impedance FCL can prevent the voltage fluctuations due to the current decline, it can cause operation speed issues, coordination troubles, overheat, and malfunction of protective components in a fault situation. This paper focused on a combination of two-way HSSCB with a self-adapt DC short current limiter, ultra-fast switch, and power electronic switch to overcome the above challenges. It can efficiently and fast fault current limiting response with low conducting loss and appropriate cooperation among protective components in a low voltage DC system. The MATLAB/Simulink is used to analyze the effectiveness and consistency of the proposed FCL-HSSCB in 400 V interconnected standalone DC microgrids.

This paper deals with the comparison approach of operational cost and consumer efforts for the smart grid system. There are two objectives considered for the smart power system i.e. the min...

This paper proposes a novel multipurpose operation planning method for minimizing the prediction error of photovoltaic power generator outputs (PV); towards reducing the operating cost and improving voltage stability of power systems. The operation schedule (coordination) of demand response (DR) program and storage system are taken into account as the main parameters for achieving an improved voltage stability and reduction of PV output prediction error. In this approach, the stochastic programming algorithm is introduced for incorporating the uncertainty of PV output and the utility demand response for consumer side management. This is achieved by using the multi-objective genetic algorithm (MOGA) for multipurpose operation plan. The MATLAB optimization toolbox and neural network toolbox were applied in this research study. An IEEE-6 bus system is used to demonstrate the effectiveness of the proposed solution in power systems operation. The approach led to $ 25003.39 ( = $ 99594.53 - $ 74591.14 ) reduction in the system operating cost, compared to the conventional approach. The simulation results also show that by using the proposed algorithm, the capacity of installed PV generators was increased and the voltage stability was improved at the same time. This accounted for the reduction in the effective operating cost and the improved operating condition of the power system.

In this report, a bidirectional WPT with a single-ended converter is constructed that satisfies the international standard of SAE J2954 for wireless EV charger. The bidirectional converter is consists of a single-ended driven by only one power switching device for practical use. It is realized a system of lightweight, low-cost and compact configurations. Previous system had two problems. One is that the transmission power varies drastically depending on the slight variations of the circuit parameter in single-ended converter. Second is that it is not possible to control the transmission power within the 85kHz band of the international standard. The theoretical analysis reveals that the control factor of transmission power is the phase difference between the power feeding side and power receiving side. A resonant capacitor selector is proposed to solve the low robustness. It is proved in simulation that high robustness is ensured compared to previous system in this control method. A combination control method of resonant capacitor selector and supply voltage changer is proposed to solve the narrow power control range. It is verified in experiment that control range of 0~6kW is ensured under 85kHz band in this control method. Moreover, only home side supply voltage changer is proposed to lower cost. Thus, wireless V2H system with a single-ended converter with a newly developed controller is realized productivity, compatibility and controllability under the international standard.

EV (Electric vehicle) solves the global warming caused by carbon dioxide, because low-loss drive under CO2/NOx free. The wireless battery charger is a promising system because of easy and safe to use for a broad range of users including the elderly. These advantages show that WPT can be the next generation charging system. However, under the case of wireless charging of EVs, there are problems such as deterioration of transfer power or efficiency due to the coil-misalignment. This paper presents a novel position detecting method with a simple configuration that provides the necessary accuracy by using a differential voltage of the auxiliary detection coils.

This research paper focuses on a prototype electric dynamic WPT operated scooter based on electric double layer capacitors (EDLCs) to develop an ecological and extremely effective motorcycle that contributes to solving global warming issues such as the lack of natural energetic reserves. This paper describes a new type of ultra-capacitor electric scooter equipped with a Wireless Power Transfer (WPT) future electricity system. Two transmission coils, a double-D coil (DD coil) and a spiral coil, are also discussed in comparison with each other. In addition, we are proposing the Multi Power Feed Dynamic Wireless Power Transfer System to extend the travel distance. The design process of the system and the fundamental performance test results are also described and considered.

In recent years, expectations for electric vehicles have been increasing as a countermeasure against global warming. A key to their widespread adoption is the development of small-size, lightweight, and low-cost electric vehicle chargers. Electric vehicle chargers with wireless power transfer (WPT) are easier to use, cleaner, and automatically than conventional wired charger. We propose a low-cost WPT apparatus with single-ended inverter based on a new type of V-groove trench SiC-MOSFET(SiC-VMOSFET), with the addition of a Kelvin source to improve gate drive. First, we describe the compact and lightweight WPT apparatus of using a single-ended converter. Second, estimated is a high power WPT apparatus which has a low on-resistance and high breakdown voltage SiC-VMOSFET. Next, we describe the new kelvin-driven SiC device using an improved Kelvin source connection and improvement of circuit pattern to reduce the switching loss.

Although the widespread use of a smart houses leads to the prevention of global warming because they do not emit CO2, batteries which is key device are so expensive that their spread is hindered. A vehicle to home system can reduce cost of the system, electric vehicles support the battery within the system. Wireless vehicle to home systems are able to remove usual vehicle to home power cables, the system will be more convenient and safe. However, wireless vehicle to home systems consist of a conventional bridged inverter using four power switching devices are expensive. Therefore, newly developed has been cost effective, compact and light wireless vehicle to home with a single-ended inverter. The vehicle to home system generally requires 6kW transfer power, which is enough to drive all apparatus of a home. Then a vehicle to home using a single-ended inverter with a synchronous parallel bi-directional control and a bi-fila transmission coils is proposed.

This paper presents a control approach for the Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion Systems (WECS) under a wide range of wind speeds. Generally, most of the wind turbines are turned-off and disconnected from the power grid, in case wind velocity is gone over 25 m/s. It may cause wind power supply shortage from wind farms. This research introduces a pitch angle controller as well as a rotational speed control system so that the PMSG based WECS can generate power if the wind speeds are above 25 m/s. The proposed method reduces the mechanical stress of the wind turbine by preferential reducing of the rotational speed rather than the mechanical torque during strong wind condition. As a result, the chance of turning-off the is reduced compared to the conventional control system because the PMSG based WECS can temporarily tolerate the wind speed up to 35 m/s. A 2 MW WECS with the electrical and mechanical characteristics is modeled in the MATLAB/SimPowerSystems® to verify the proposed research.

This paper proposed the wind sensorless identification method for wind turbine using online parameter identi cation. In the proposed On-line parameter identification is used to identify the parameter $k_{opt}$ and improve the characteristics in optimal torque control that does not require wind speed information. The parameter identification is performed using the Recursive least squares method in the wind turbine using PMSG. Further, the identied optimal parameter $k_{opt}$ contributes to the detection of all parameter error of the wind turbine and characteristic change with aged deteriorations. The effectiveness of the proposed identi cation method was veried by simulations with using MATLAB / SIMULINK.

This paper presents a smart house-based power system for thermal unit commitment programme. The proposed power system consists of smart houses, renewable energy plants and conventional thermal units. The transmission constraints are considered for the proposed system. The generated power of the large capacity renewable energy plant leads to the violated transmission constraints in the thermal unit commitment programme, therefore, the transmission constraint should be considered. This paper focuses on the optimal operation of the thermal units incorporated with controllable loads such as Electrical Vehicle and Heat Pump water heater of the smart houses. The proposed method is compared with the power flow in thermal units operation without controllable loads and the optimal operation without the transmission constraints. Simulation results show the validation of the proposed method.

This paper deals with an optimal battery energy storage capacity for the smart grid operation. Distributed renewable generator and conventional thermal generator are considered as the power generation sources for the smart grid. Usually, a battery energy storage system (BESS) is used to satisfy the transmission constraints but installation cost of battery energy storage is very high. Sometimes, it is not possible to install a large capacity of the BESS. On the other hand, the competition of the electricity market has been increased due to the deregulation and liberalization of the power market. Therefore, the power companies are required to reduce the generation cost in order to maximize the profit. In this paper, a thermal units commitment program considers the demand response system to satisfy the transmission constraints. The BESS capacity can be reduced by the demand response system. The electric vehicle (EV) and heat pump (HP) in the smart house are considered as the controllable loads of the demand side. The effectiveness of the proposed method is validated by extensive simulation results which ensure the reduction of BESS capacity and power generation cost, and satisfy the transmission constraints.

The recent global trend in automation and smartness has boosted the need for innovation in microgrid that led to a renewed interest in researches and innovations in this context. This paper steers a plenary counseling and discussion in the context of microgrid planning and design for academia, industry, planners, utility operators, regulators, policymakers to disseminate the recent innovation and available barriers ahead of a microgrid in the 21st century. Most published researches on microgrid covered specific areas. Exclusively, the thesis of this paper addresses a pivotal question, based on a transdisciplinary approach including technical, managerial, economic, and sustainability criteria. This study addresses that how to scale and manage a microgrid's technical and economic diversities, to align with local resiliency. By the help of a semi-empirical methodology, an exhaustive roadmap is proposed in form of a systemic solution that contributes to ensure sustainability and resiliency in term of a microgrid project management and operation.

Due to the interconnected scheme of multiple components, such as distributed generators, storage systems, and loads through converters to a common bus in DC microgrids, the possibility of fault occurrence is increasing significantly. Meanwhile, due to the huge and rapid increase of short-circuit currents, the development of a small- and large-scale DC system requires a reliable and fast protection system to ensure fault clearance and maintain safety for the rest of the system. Thus, fault protection has been focused on as one of the most critical issues in a direct current network. The application of traditional circuit-breakers for DC fault protection has the drawback of slow operation, which requires a high rating power equipment. Recently, the high speed and excellent performance capabilities of semiconductor breakers have attracted a lot of attention and been considered as an optimal solution for fast DC fault interruption. In this study, a bidirectional Insulated-Gate Bipolar Transistor (IGBT) semiconductor breaker, suitable for the fault protection of low-voltage DC networks, is proposed. The operating characteristics of this breaker are based on changes in the circuit current and terminal voltage of IGBTs. It detects the abrupt change of the terminal voltage as an abnormal condition and isolates the faulted branch in a short time to prevent the operation disturbance in the healthy part of the network. Therefore, for the entire protection of a typical 400V DC-microgrid cluster, breakers need to be integrated and examined in each branch and the interconnected lines. The proposed protection method in this study is examined in a Simulink®/MATLAB environment to analyze and assess its operation.

Renewable energy sources (RESs), as clean, abundant, and inexhaustible source of energy, have developed quickly in recent years and played more and more important roles around the world. However, RESs also have some disadvantages, such as the weakness of stability, and by the the estimated increase of utilizing RESs in the near future, researchers began to give more attention to these issues. This paper presents a novel output power fluctuate compensation scheme in the small-scale power system, verifying the effect of output power control using storage battery, demand-response and RESs. Four scenarios are considered in the proposed approach: real-time pricing demand-response employment, RESs output control use and both of demand-response and RESs output control implementation. The performance of the proposed control technique is investigated using the real 10-bus power system model of Okinawa island, Japan. Moreover, the system stability is checked using the pole-zero maps for all of the control loops associated with the proposed scheme. The robustness and effectiveness of the proposed method was verified by simulation using Matlab ® /Simulink ® .

Every nations' socio-economic development directly depends on the corruption index. Turn the tide toward sustainable development, corrupted-free society along with socio-economic prosperity would not be possible without relying on the lessons learned from other nations, which overcome this problem. This study unlike the literature, designed an appropriate framework that aligning the sustainability, management, technical, technological aspects of an overall technology (ICT-Information and Communications Technology) within sustainability objectives. As well as, this study set out to develop an anti-corruption schematic platform (a basic concept at this stage using mobile/PC application) for corruption effective reduction considering the real-life acceptance condition of the least developing nations. With an ultimate aim to add value to the prosperity trend and alleviate the corruption rate. The proposed schematic platform for anti-corruption elimination in term of the developing nation, ultimately contributes to achieve the goals of global and national levels' endeavor toward transparency by deploying the proposed solution as a pilot project for a long-run sustainability.

Recently, the number of generation facilities using renewable energy is increasing, and HVDC attracts attention. With the proliferation of HVDC, it is expected that MTDC will be formed with complicated transmission system. Although HVDC is a promising system, there is a problem with system protection. For DC systems, faults must be detected and removed at high speed. Therefore, this paper proposes a fast fault detection method by measuring current slope using current differential information. With this proposed method, faults can be detected at high speed, and faulty areas and types can be distinguished.

From the perspective of global warming suppression and the depletion of energy resources, renewable energies, such as the solar collector (SC) and photovoltaic generation (PV), have been gaining attention in worldwide. Houses or buildings with PV and heat pumps (HPs) are recently being used in residential areas widely due to the time of use (TOU) electricity pricing scheme which is essentially inexpensive during middle-night and expensive during day-time. If fixed batteries and electric vehicles (EVs) can be introduced in the premises, the electricity cost would be even more reduced. While, if the occupants arbitrarily use these controllable loads respectively, power demand in residential buildings may fluctuate in the future. Thus, an optimal operation of controllable loads such as HPs, batteries and EV should be scheduled in the buildings in order to prevent power flow from fluctuating rapidly. This paper proposes an optimal scheduling method of controllable loads, and the purpose is not only the minimization of electricity cost for the consumers, but also suppression of fluctuation of power flow on the power supply side. Furthermore, a novel electricity pricing scheme is also suggested in this paper.

High-voltage direct current (DC) transmission systems and multi-terminal direct current transmission systems are attracting attention for expanding the grid to promote introduction of renewable energy. Fault clearing in DC systems is difficult because there is no zero point of current. Hybrid circuit breakers are suitable for fault clearing in DC systems. Conventional hybrid circuit breakers have a hard-switching path that damages the switch. Hard switching damages the device and produces emissions due to harmonic noise. A novel resonant hybrid DC circuit breaker is proposed in this paper. The proposed circuit breaker reduces the damage to the switching device using soft switching due to the current zero point. The proposed circuit breaker is compared with conventional hybrid circuit breakers using numerical simulations. Interruption times and switching types of circuit breakers were compared. The simulation results of the fault clearing characteristics of the proposed breakers show that the proposed breakers have sufficient performance and are capable of stable reconnections in multi-terminal direct current transmission systems.