Showing papers in "Journal of International Council on Electrical Engineering in 2017"

Multi-agent systems and their applications

Abstract: The number of distributed energy components and devices continues to increase globally. As a result, distributed control schemes are desirable for managing and utilizing these devices, together wit...

Open-circuit fault detection in distribution overhead power supply network

Abstract: CLP’s distribution overhead line network supplies electricity to its customers in rural areas. The lines exposed outdoors are vulnerable to external and environmental interferences. When op...

Design and Implementation of a smart monitoring system of a modern renewable energy micro-grid system using a low-cost data acquisition system and LabVIEWTM program

Abstract: This paper focuses on designing and implementing a prototype of smart monitoring system capable of doing multi functions i.e. monitoring, analysing and communicating with devices in a small micro-grid system. This research proposes the use of a combination between a low-cost data acquisition (NI compact DAQ) device and a commercially-used LabVIEW™ program in being a smart renewable monitoring and analysing system. The proposed set of equipment is capable of doing all the functions needed by utilities and users in the aforementioned micro-grid system. The proposed prototype is capable of measuring, monitoring and recording in both normal system operating conditions and when faults occurred. A number of power quality parameters that can be monitored and analysed are as follows: voltage (V), current (I), real power (P), reactive power (Q), apparent power (S), energy consumption (kWhr), power factor (PF), harmonics distortion (THDi and THDv), over/under voltage, sag as well as swell. Extensively in th...

Application of PV Inverter on distribution system with high penetration of PV

Abstract: In the near future, distribution power system will experience some problems because of the getting higher penetration of photovoltaic (PV) generations. Under certain high PV penetration level, the ...

Influence analyses of harmonics on distribution system in consideration of non-linear loads and estimation of harmonic source

Abstract: Recently, non-linear loads have diversified and increased. It results in deterioration of power quality on a distribution system, since the equipment, which includes the non-linear loads, generates harmonics. The harmonics cause not only deterioration of power quality but also further various problems. Nowadays, the state of harmonics is becoming evident by the recent researches. However, since the harmonic analysis by using a detailed model of distribution system is too difficult, the analysis is carried out by a simplified model. In this paper, the authors construct an analytical distribution system model in consideration of the non-linear loads with the harmonic sources based on the practical data. Moreover, the influence analyses of harmonics are carried out by using this model. In addition, the authors estimate the harmonic sources in the simplified distribution system.

Differential electromagnetic analysis for PRESENT and its evaluation with several selection functions

Abstract: Since Internet of Things (IoT) devices, such as sensor device or automotive equipment, become widespread, the security of IoT devises is very important. These IoT devices have constraints on the area and the power consumption. Therefore, lightweight block ciphers which have small area and low power have attracted attention. PRESENT is one of the most popular lightweight block ciphers. Regarding the hardware security, the risk of electromagnetic analysis for a cryptographic circuit is pointed out. Differential electromagnetic analysis (DEMA) is typical electromagnetic analysis method. Regarding the verification of tamper resistance, previous studies show difference of selection function in DEMA affects the tamper resistance greatly. Therefore, this study proposes an electromagnetic analysis for PRESENT. The proposed method performs an analysis based on DEMA. Moreover, this study verifies the tamper resistance of PRESENT against DEMA using several selection functions. Experiments using a field progr...

Proposal and effect evaluation of RPC application with energy storage system for regenerative energy utilization of high speed railway

Abstract: All car of Tohoku-Shinkansen is equipped with the regeneration brake. This car is returning electric power to the Catenary line when it is braking. Regenerative power can improve the energy efficiency if other cars can use regenerative power. But the regenerative power flows back to the grid via the traction substation when other train does not exist in the same section. At this time, the regenerative power flowing back is not metered. This study is to measure the regenerative energy that flows back to the grid. We need determine the equipment capacity if installing the electric energy storage systems and the RPC for use up regenerative power. By using a linear programming, we determined the optimal capacity of the electric energy storage systems and the RPC.

A novel frequency estimation algorithm based on DFT and second derivative

Abstract: In this paper, a novel frequency estimation algorithm based on discrete Fourier transform (DFT) and second derivative is proposed. The proposed algorithm consists of three stages, namely, DFT, second derivative, and frequency estimation. First, the input signal is decomposed using DFT into two orthogonal components, the real and imaginary parts. In other words, the signal is filtered with cosine and sine filters. Secondly, the second derivatives of the two orthogonal components are obtained by numerical approximation. Because this step can cause an error, the central difference approximation for five-point second derivative is used for error reduction. Finally, the two orthogonal components and their second derivatives are combined to estimate the power frequency considering a zero-crossing problem and the gains of finite impulse response (FIR) filters. The performance of the proposed algorithm is evaluated considering frequency changes when generating the test signals. Besides, a dynamic conditio...

Power systems inertia evaluation associated with PV installation by frequency analysis of inter-area oscillation based on phasor measurements

Abstract: Recently, RES (renewable energy sources) have been introduced to realize a low carbon society. Installation of PV (Photovoltaics) is especially noticeable recently. RES, however, do not have inerti...

Analysis of peak shaving effect of demand power using Vehicle to Grid system in distribution system

Abstract: In general, most vehicles are parked during the peak load time so that if we could control these Electric Vehicles suitably and provide the stored electricity from vehicle (battery) to grid, electrical peak load would be reduced. Above function is called as a Vehicle to Grid (V2G). In this paper, we propose the peak load shaving scheme to reduce the peak demand and analyze the effect of V2G system for the peak load shaving in the actual distribution system considering various penetration level of EVs. With the proposed method, peak demand power is reduced considerably.

Effective length of vertical grounding wires connected to wind turbine foundation

Abstract: Wind turbines are frequently struck by lightning. One of the important and effective measures is to reduce the grounding impedance of wind turbine. For the reduction of grounding impedance, vertica...

Common-mode magnetic field rejection-type magneto-impedance gradiometer

Abstract: We have developed a common-mode magnetic field rejection-type magneto-impedance (MI) gradiometer to reduce the common magnetic field applied to the sensing- and reference-type MI elements. Compared with a general-type MI gradiometer, the magnetic noise spectral density was lower and the noise at 60 Hz related to the power source line was reduced by 1/8. Using the developed sensor, we successfully detected a microscopic 5 nT magnetic signal in a common-mode magnetic field that was 14 times larger. We expect this will lead to a simpler method of detecting microscopic magnetic signals such as biomagnetism without the need for magnetic shielding.

Control methods for an energy storage system when wind power output deviates from grid code

Abstract: Because of the rapid growth of wind power, an electric grid company set the maximum change rate in a time window to share its fluctuation; this set maximum change rate in a time window is called the grid code. Large fluctuations of wind power may cause deviation from the grid code, but no studies discuss how to control an energy storage system (ESS) so that it quickly goes back to satisfying the grid code. The authors proposed three control methods for an ESS when the wind power output deviates; they are (1) ‘restart’, (2) ‘continuance without operation’, and (3) ‘continuance with operation’. One year numerical simulations with two types of grid codes and two wind power output data have been performed to evaluate the methods. From the studies, control method (3) is found to be the best control method for an ESS to minimize capacity when the wind power output deviates from the grid code, and is verified by the numerical simulations. These results help to answer questions on how to reduce deviation ...

Efficiency improvement of rooftop photovoltaic system at railway station

Abstract: The partial shadows on the photovoltaic (PV) system are widely recognized to slightly influence the amount of generation power. The power output drop does not clearly break out according to the act...

Lightning protection for wind turbines in Vietnam

Abstract: Wind energy has become increasingly important in the total electrical energy supply mix in Vietnam over the last few years. Small, kW turbines were installed in isolated areas a decade ago, while wind farms of several MW to few hundred MW are now being connected directly to national grid, with many additional projects in planning or under construction to fulfill an objective of 6% of the total installed capacity by 2030 (approximately 6200 MW of wind energy component). The increase in wind farm generation results in increased damage from lightning. In this paper, the annual frequency of lightning strikes to wind turbines in Vietnam is calculated using electrogeometric model. Reported lightning incidents to three major wind farms in Vietnam are summarized. Possible causes of failure are discussed, and an EMTP simulation for each incident was performed accordingly. The simulations suggest the failure mechanisms as well the potential of improved grounding to reduce lightning induced damage in future ...

Implementation of module-based wind power system with pitch angle control

Abstract: This paper presents a module approach for lab-scale wind power systems (WPS). The system is designed into functional modules. These modules can be used independently or in other projects. It is also convenient to handle and set up them on a small table in classrooms and labs. Hence, they are very useful for training and research. In addition, operation on both aerodynamic side and generator side is developed in this research. Many papers on wind system simulators focus only on aerodynamic system with pitch angle control or generator system with optimal control. Thus, the operation of WPS in 2 regions, which requires coordination of aerodynamic and generator sides, is not explained and demonstrated in previous study. Many case studies are conducted to demonstrate the capability of the module-based WPS. The system is capable of speed control, optimal power control and pitch angle control. As illustrated in experimental results, these control strategies can efficiently cooperate under operation in 2 ...

Estimation of potential demand reduction by commercial air conditioner control considering outdoor air temperature

Abstract: Demand response is expected to help maintain the supply and demand balance of the power system. In Japan, various demonstration projects have been carried out to evaluate the effect of demand reduction. Commercial air conditioners are a promising responsive load for demand response because they account for a large proportion of power consumption in the power system. In this study, we estimate the potential for system-wide demand reduction through controlling commercial air conditioners. Power consumption of air conditioner changes by the outdoor air temperature. The air-conditioning power consumption model is established based on efficiency characteristics of air conditioner depending on outdoor temperature and load factor. A thermal load simulation is performed assuming demand response implementation in the model buildings and the potential demand reduction is estimated considering user comfort. Our results show that demand reduction through air conditioner control is a viable strategy.

Moving object tracker using sensor fusion of ultrasonic range finder and accelerometer

Abstract: We present an accurate real-time moving object tracker using an α–β–γ filter for a position/acceleration sensor fusion system comprising ultrasonic range finders and an accelerometer. For this sensor fusion system, an optimal and stable α–β–γ filter receiving simultaneous measurements of position/acceleration is introduced based on a minimum-variance filter criterion. Numerical analyses and simulations verify its effectiveness in terms of stability, accuracy, convergence speed, and simplicity in parameter design. Experiments demonstrate its efficacy as a realistic tracking system and verify that the proposed α–β–γ filter achieves faster convergence and better accuracy than conventional position-only-measured α–β–γ filters with a steady-state error of 70% that of a conventional α–β–γ filter.

Geared induction motor fault diagnosis by current, noise and vibration considering measurement environment

Abstract: Lots of motors have been being used in industry. Therefore many studies have been carried out about the failure diagnosis of motors. In this paper, a diagnosis of gear fault connected to a motor sh...

Operation algorithm of PV/BESS application considering demand response uncertainty in an independent microgrid system

Abstract: Various renewable energy sources, such as wind and solar photovoltaic (PV) cells, are now being used in power systems. Meanwhile, few new steam power plants and transmission lines are being constructed because of the environmental problems they cause. As an alternative, small-scale independent power systems with energy-storage systems such as microgrids are increasing. In a small microgrid system that is vulnerable to frequency variation, coordinating an optimized scheduling between the energy-storage system and renewable energy generation is important. However, considering the uncertainty of weather forecasting and uneven load patterns, several cases should be considered. In this paper, the operation algorithm of a stable PV/BESS system is proposed. This system contributes helps decide the output battery to design battery capacity as a contingency for unexpected situations in a microgrid system.

Non-contact guide system for travelling elastic steel plate (Optimal placement of electromagnets by analysis of steel plate shape)

Abstract: In a factory, continuous thin steel plates are supported by a series of rollers during such processes as plating and rolling. Because the rollers come in contact with the steel plates, the problem of surface quality deterioration arises. To solve this problem, we developed a non-contact guide system for parts of the steel plate where the travelling direction changes by applying an electromagnetic force and experimentally examined the effectiveness of the system. In this study, the shape of the travelling steel plate is calculated by numerical analysis. Based on the results, we confirmed the validity of the proposed system.

A study of impact on power system stability originated from new islanding detection method in PV systems

Abstract: In Japan, a unique islanding detection method, named New Islanding Detection Method, is widely equipped with grid-tied photovoltaic generation systems (PVs) to accurately detect their islanding operation. However, some research results show that the extensive installation of new islanding detection method brings negative impacts on stability of main power grids. This is because the islanding detection method has a possibility to detect frequency fluctuation caused by main grid’s faults, and the resulting undesirable operation intensifies the frequency fluctuations more. The authors especially focus on a frequency feedback mechanism in the islanding detection method, and then clarify some impacts on the stability of main grids which are originated from the growth in penetration of the islanding detection method in PVs. Through numerical simulations and discussions on their results, the authors concluded as, (1) the transient stability can be improved when active power output of PVs are set to const...

Defensive control of VSWT-PMSG system against network disturbance impacts

Abstract: In the future, a lot of VSWT-PMSGs (Variable Speed Wind Turbine – Permanent Magnet Synchronous Generator) will be interconnected to the power system. The characteristic of VSWT-PMSG is that the wind turbine and the power system are interconnected by back-to-back converter. For this reason, PMSG doesn’t synchronize to grid side. In a conventional control strategy, network disturbance impacts propagate DC link, and a capacitor and a parallel protection resistance in it are deteriorated. In this paper, new control strategy of generator side converter is proposed in order to realize that a network disturbance impact propagates PMSG. As a result, elements in DC link don’t absorb a network disturbance impact fully and thus quality reduction becomes slower. In this paper, such control strategy for converters is given as a basic study and it is referred as ‘defensive control’.

Derivation of reliability parameters through reliability analysis and life test of clutch & brake for washing machine

Abstract: To derive the reliability parameters of clutch & brake, as a first step, we made out the failure analysis data, and we analyzed the cause of major failures, and decided the main test items through 2-stage QFD As the next step, the complex tests were performed as like performance tests, environmental tests, saftey tests, and life test Through the results of life test, we decided the reliability parameters of clutch & brake by using of MINITAB software Then we verified propriety the reliability parameters by comparison of pre-performed test results and MINITAB analysis In this paper, we proposed a method of the reliability assessment technology of clutch & brake, and showed the reliability parameters of clutch & brake by use of 10-sample clutch & brakes for washing machine And also, we presented the useful reliability parameters for clutch & brake test, which are produced by MINITAB analysis and marking of Weibull probability paper using the measured some life points, and also verified the prop

High frequency short-circuit inductance for model transformer

Abstract: Currently, the International Electrotechnical Commission (IEC) standard (IEC62271-100) requires that the transformer limited fault (TLF) interruption shall be verified in the test duty T10, the amplitude factor of which is defined as 1.7 for the transient recovery voltage (TRV). But, the TRV measurements for the TLF at various transformers show that the factor is mostly lower than 1.7. The reason for the low values is considered to be that the short-circuit inductance of transformer at the TRV frequency region is lower than that at the power frequency, and consequently the factor is lower than the standard value 1.7. But, the frequency-dependence of the short-circuit inductance of transformer has not been clarified yet. We measured the short-circuit inductances of model transformer with and without the iron core. The short-circuit inductance with the iron core becomes small and equals to one without the iron core at the TRV frequency region. We concluded that this is the reason for the phenomena o...

Development of partitioned stator flux-switching machines for electric vehicles

Abstract: In this paper, three advanced partitioned stator flux-switching permanent-magnet (PS-FSPM) machines with different number of phases, namely the 3-phase, the 4-phase, and the 5-phase are comprehensively compared. Owing to the higher-phase topology, better fault-tolerability and higher power density can be achieved. On the other hand, higher-phase machine suffers from the problem of relatively lower cost-effectiveness. Hence, trade-off between different criteria should be considered to fulfill various situations. In particular, all the PS-FSPM machines are highly favorable for the electric vehicle applications, while all of their key performances are analyzed with the support of the finite element method.

Power drop detection in PV string by analyzing I–V characteristics

Abstract: Photovoltaic (PV) systems have been regarded as maintenance-free; however, numerous failures have been reported recently during their operation. These failures not only cause power drops in the PV system but can also lead to serious accidents. This paper proposes a diagnosis method that utilizes the current–voltage (I–V) measurements of the PV string to detect the existence of a power drop module in the PV system. This diagnostic methodology is based on the calculation of the decrease in the area of the string I–V curve and dP/dV–V characteristic from the obtained data. A power drop module in the PV string is assumed and calculated. First, the normal and failed versions of the PV string are distinguished by plotting the decrease in the area of the I–V curve on one axis and the ratio of the power drop on the other axis. The differences among each failure mode are then obtained by evaluating the dP/dV–V characteristic of the PV string. Finally, experimental tests are performed on the PV string to va...

Evaluation of battery capacity required for assist of balancing control

Abstract: The growth of Renewable Energy Sources (RES) requires more reserve for generation-demand balancing. In recently, energy storage system such as battery is focused on as additional reserve power sour...

Proposal of novel hybrid-MEID mechanism for shock response control -A method with time-difference-operation of passive and active motions

Abstract: Several mechanisms have been proposed to solve shock response control problems in vehicle engineering. The momentum exchange impact damper (MEID) mechanism has been considered for solving shock response control problems in spacecraft landing systems. The effectiveness of MEIDs against the shock responses of a running cart collision problem was investigated using simulation. A novel hybrid MEID mechanism is proposed by considering the time-difference operation of both passive and active MEIDs to optimize the actuator parameters. In this time-difference hybrid MEID (TDHMEID), the amount of passive momentum exchange can be easily identified. Therefore, TDHMEID can be used to set the optimal parameters for active actuator operation. The effectiveness of the TDHMEID mechanism on controlling the shock response and saving actuator energy is verified by simulation.

Characteristic comparison of different resonators to extend transfer distance in superconducting wireless power transfer for electric vehicle using high temperature superconducting resonance coil

Abstract: This paper presents the feasibility of technical fusion between wireless power transfer (WPT) based on resonance coupling system and superconducting technology to improve the transfer efficiency and spread the electromagnetic field widely in spite of small size coils. Until now, the various copper wires have generally been adopted in WPT system. From this reason, the transfer efficiency is limited since the copper wire keeps low Q intrinsically. On the other hand, as superconducting wires keep larger current density and higher Q value, the superconducting resonance coil can be expected as a reasonable option to deliver large transfer power as well as improve the transfer ratio since it exchanges energy at a much higher rate and keeps stronger magnetic fields out. In this study, we examined the transmission ratio using HTS and cooper wires in the antenna (Tx) or/and receiver (Rx) within input power of 500 W under various performances; copper Tx to copper Rx, HTS Tx to copper Rx, copper Tx to HTS Rx...