Shu Fan,Chengxiong Mao,Luonan Chen,Electricity peak load forecasting with self‐organizing map and support vector regression,IEEJ Transactions on Electrical and Electronic Engineering (2006)1(3)330‐336

The original article to which this Erratum refers was published in IEEJ Transactions on Electrical and Electronic Engineering IEEJ Trans Electrical Electron Eng (2006) 1(3) 330 .     

Calculation of the loss‐minimum configuration in the IEEJ local power system model

In Japan, local power systems (77 kV) are served from the 275‐ or 154‐kV substations. For enhancement of power supply reliability, the transmission lines are connected to several substations, and the operational configuration is radial. The local power system's configuration is determined by connecting and disconnecting transmission lines so as to keep the radial structure and satisfy the operation constraints. When a local power system has a number of transmission lines, many configuration candidates occur. Recently, an IEEJ committee made a practical scale local system model (IEEJ Local System Model). Since the IEEJ Local System Model has 76 transmission lines, the total number of configuration candidates is 2⁷⁶ (approximately 7.5 × 10²²). In this paper, the authors try to strictly obtain the loss‐minimum configuration under constraints such as substation capacity, line capacity, and radial structure in the IEEJ Local System Model. In order to obtain the optimal configuration, a new computation algorithm is proposed. In the proposed algorithm, the configuration determination problem is replaced as two combinatorial optimization problems based on the operational constraints [(1) substation capacity, (2) line capacity, and (3) radial structure]. One combinatorial optimization problem (subproblem 1) is to pick up all partial configurations so as to minimize total line loss under the substation capacity constraint. By using the enumeration method, subproblem 1 is solved. Subproblem 2 is solved by using the reduced ordered binary decision diagram (ROBDD). Since the proposed method is based on enumeration and Boolean function, the optimality of obtained solution is guaranteed. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 34–42, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10226     

Visualization system for electrical power consumption and its evaluation

A visualization system for power consumption has been developed. This system has two power measurement devices: a smart power strip that assesses each attached electric device; and a power sensor on the power distribution board. To verify the effectiveness of this system, an evaluation system has also been developed. Results indicate that the relative deviation of the visualization system is around 1% and that its uncertainties are less than 0.4% at 500 W/50 Hz. IEEJ Trans 2011 DOI: 10.1002/tee.21800     

A starting method of the harmonic current compensator using a hybrid active filter for wind power generation systems with soft starters

This paper proposes a starting method of the harmonic current compensator using a hybrid active filter for wind power generation systems. The active filter (AF) in the proposed method of the hybrid power filter behaves as a resistor and reactive power compensator to suppress the inrush current and leading currents for the passive filter (PF) under the starting condition. The basic principle of the proposed starting method is discussed, and then confirmed by digital computer simulation using PSCAD/EMTDC. Simulation results demonstrate that the proposed starting method can overcome the inrush and leading currents for the PF, building up the DC capacitor voltage of the AF. IEEJ Trans 2011 DOI: 10.1002/tee.21815     

Recent advances and outlook in industrial instrumentation and mechatronics control

Recent years have been characterized by marked progress in industrial instrumentation and mechatronics control technology. This year commemorates the fifth publication year of the IEEJ Journal of Industry Applications (emIEEJ J. IA). Additionally, the Mechatronics Control (MEC) technical committee was formed 3 years ago following a separation from the Industrial Instruments and Control (IIC) technical committee in order to further enhance their respective social contributions. The increased activity of both committees also contributed to the progress of the Journal. This paper discusses the recent advances and outlook in the technical field of industrial instrumentation and mechatronics control based on papers published in the IEEJ J. IA and a few other significant papers, which consider the current activities of the various committees. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Reduced order model predictive control with disturbance attenuation

This paper deals with model predictive control (MPC) with disturbance attenuation. By introducing a decomposition method for a quadratic objective function, an MPC law is obtained from a reduced order optimization problem. The effectiveness of the proposed MPC law is demonstrated by numerical simulation. IEEJ Trans 2010 DOI: 10.1002/tee.20613     

A solution of optimal power flow with multicontingency transient stability constraints

This paper presents a formulation of the multicontingency transient stability constrained optimal power flow (MC-TSCOPF) problem and proposes a method to solve it. In the MC-TSCOPF formulation, this paper introduces a modified formulation for integrating transient stability model into conventional OPF, which reduces the calculation load considerably. In our MC-TSCOPF solution, the primal-dual Newton interior point method (IPM) for nonlinear programming (NLP) is adopted. Computation results on the IEEJ WEST10 model system demonstrate the effectiveness of the presented MC-TSCOPF formulation and the efficiency of the proposed solution approach. Moreover, based on quite convincing simulation results, some phenomena occurred when considering multicontingency are elaborated.     

A maximum power point tracking control method suitable for compact wind power generators with the passive self‐pitch‐controlled blade structure

This paper describes a maximum power point tracking (MPPT) control method for propeller‐type compact wind power generators with passive self‐pitch‐controlled blades, which quickly makes the output current and voltage converge on the maximum power point based on wind speeds detected from an anemometer. The voltage and current output from these wind power generators vary with wind speeds at locations such as the roofs of buildings. Transient characteristics of the voltage output from compact wind power generators have two modes because of the self‐pitch‐controlled blades: mode I in which the output voltage hardly increases and mode II in which it rapidly increases. Thus, in order to acquire the generated power effectively, irrespective of how the wind speeds may change, a method to perform the MPPT control while searching for mode II is needed. Thus, by judging the mode from the change of the sign of the time differential of the voltage deviation between sampling times, the MPPT control method proposed here makes the output current converge on the maximum point using relationships between the maximum power and optimal current which give the maximum power and the wind speed. Effectiveness of the proposed MPPT control method is verified through simulations and experiments using a wind tunnel. IEEJ Trans 2010 DOI: 10.1002/tee.20609     

Development of an eigenvalue estimation method (Mode Coupling Method) for small signal stability analysis of power system

An eigenvalue estimation method for small signal stability analysis of electric power systems is proposed. The method, called the Mode Coupling Method, is used to estimate efficiently the nonlinear change of the eigenvalue with respect to the change of parameter. The eigenvalue sensitivity analysis method, which has been used to estimate the change of the eigenvalue, is a method of linear estimation of the change of the eigenvalue. However, the eigenvalue frequently shows a strong nonlinear change, and therefore the calculation efficiency and speed were insufficient in the conventional method. In the Mode Coupling Method, the most important modes and those most related to the major mode under consideration are first selected. Next, these two or more selected modes are coupled and the new eigenvalues of the coupled matrix are calculated, providing good estimation of the new eigenvalues. The size of the coupled matrix is very small. We can consider mutual interaction between important modes. Thus, this is a powerful method in which nonlinear estimation of eigenvalues is possible. When the QR method is used, the calculation time for eigenvalue analysis is proportional to the third power of the size of the matrix. The size of the matrix used for the mode coupling method is approximately 1/6 of the original value. Therefore, the computing time for eigenvalue estimation becomes less than 1% of the original computing time. The computational accuracy of the proposed method is verified with the IEEJ EAST30 standard power system model. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(1): 10–16, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/ eej.21037     

Enhancing small‐signal and transient stability performances in power systems with integrated energy function and functional sensitivity

Small‐signal and transient stability of a power system can be improved by installing power system stabilizers (PSSs) inside the excitation controls of the generators. Nonetheless, designing and tuning the PSSs' parameters to suit all operating conditions is a complex and difficult task. Therefore, a new control scheme integrating the principles of the energy function and the functional sensitivity is proposed in this paper. The performance of this control scheme in terms of critical clearing time, simulated dynamic responses, and power oscillation damping was examined using the IEEJ West 10‐ machine test system. Test results reveal that the proposed scheme can improve both small‐signal and transient stability performances under various operating conditions and contingencies. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Economical load dispatching method considering power plant dynamics

To reduce boiler fuel cost, a new ELD (economic load dispatching) method based on a dynamic fuel cost model, which is more accurate than the conventional quadratic model, is proposed. First, an ARMA (autoregressive moving average) model, which is constant‐coefficient linear digital filter, is applied in order to supplement the quadratic model. We call this the supplemented model ARMA‐model‐supplemented quadratic model. By using this model, the model deviations from actual data have been reduced. Second, based on the ARMA‐model‐supplemented quadratic model, we formulated the ELD problem as a quadratic programming problem, where the objective function is the summation of all units' fuel costs over multiple time points and the constraints are the supply–demand balances, the upper and lower generation limits, and the ramp rate limits. This problem can be solved by the standard quadratic programming technique. We call this new ELD method BEST (boiler‐dynamics‐based economical load dispatching) method. Then, in order to make the problem size smaller, we propose a scheme to ignore all time points except for those corresponding to the peak, the bottom, and the steepest point on the forecasted load curve. We call this scheme the sample scheme. Finally, the BEST method with the sample scheme is evaluated by numerical simulations on the Kansai Electric Power Co. system and it is shown that the proposed method can reduce the calculation time without compromising the fuel cost. © 1999 Scripta Technica, Electr Eng Jpn, 127(1): 39–46, 1999     

The effect of nano‐ZnO on corona aging and photo aging in low‐density polyethylene

In this paper, space charge distributions as well as dielectric properties, such as volume resistivity and AC breakdown strength, were studied in low‐density polyethylene (LDPE) and its composite obtained by adding nano‐ZnO nanofiller, before and after photo‐oxidation or corona aging for several days. It was found that a small amount of ZnO nanoparticles could effectively improve both the photostabilization and corona stabilization of the LDPE matrix. Fourier transform infrared (FTIR) spectra of the specimens were investigated to reveal the change of the microstructures. The results showed that a weaker carbonyl absorption peak appeared in LDPE/ZnO nanocomposite than in LDPE. A proper explanation is given according to the photodegradation and corona degradation theory of polyethylene. The results also showed that there was a certain similarity between photo aging and corona aging. IEEJ Trans 2010 DOI: 10.1002/tee.20600     

Characteristics of the compact plasma device AIT‐PID with multicusp magnetic confinement

A unique plasma‐generation device called the “Aichi Institute of Technology‐Plasma Irradiation Device” has been developed for plasma–wall interaction (PWI) studies toward realization of a fusion reactor. It has power‐saving characteristics as well as compactness due to the employment of a multicusp magnetic field configuration instead of a strong axial magnetic field. Helium as well as argon plasmas are generated, showing an outstanding property of production of the hot‐electron component which can be controlled by changing the working gas pressure. Utilizing such outstanding properties, some typical studies on PWI are introduced. An azimuthally asymmetric confinement depending on the direction of magnetic field lines, particularly for energetic electrons, has been found. Some discussions on the physical mechanisms are given. IEEJ Trans 2011 DOI: 10.1002/tee.21801     

宝钢集团能效电厂的应用

能效电厂是推进节能减排的重要手段,同时对电网的经济运行和安全稳定也具有重要意义。介绍能效电厂的概念,针对在钢铁企业中建设能效电厂的课题进行了探讨,根据钢铁企业电能耗散的自身特点,提出了在钢铁企业中能效电厂建设的措施与思路,从电能来源、电能传递、电能转化与使用3个阶段实施能效电厂建设项目,为钢铁企业建设能效电厂提供借鉴。     

Numerical study of the oscillation characteristics of a surface wave oscillator

The oscillation characteristics of a surface wave oscillator is analyzed numerically. The oscillation frequency due to Cherenkov instability can be controlled by the electron beam energy though the alteration of the accompanying temporal growth rate. The growth rate increases exponentially with the proximity of the beam to a corrugated metal plate. The oscillation frequency is not changed by this proximity. The peak of the growth rate of the Cherenkov instability is one or more orders higher than that of a Smith–Purcell type instability. Moreover, in frequency and wavenumbers, the difference of two instabilities is enlarged by the increase in the growth rate. Therefore, the influence of the Smith–Purcell type instability on the Cherenkov instability is decreased. IEEJ Trans 2010 DOI: 10.1002/tee.20611     

Recognition of control chart patterns using swarm intelligence and neural networks based on the statistical and shape features

Automatic recognition of abnormal patterns in control charts has seen increasing demands nowadays in the manufacturing processes. In this paper, a hybrid intelligent system is proposed for the recognition of control chart patterns. In this system, we have used a proper set of shape features and statistical features as the efficient characteristics of the patterns. Then we proposed a hybrid heuristic recognition system based on particle swarm optimization to improve the generalization performance of the radial basis function neural network classifier. For this purpose, we have optimized the classifier design by searching for the best value of the parameters that tune its discriminate function. The obtained results show that the proposed technique has high recognition accuracy in comparison with other techniques. This recognition accuracy is achieved with fewer training samples. IEEJ Trans 2010 DOI: 10.1002/tee.20610     

Numerical analysis of low‐frequency properties in single‐junction thermal converters

We have performed numerical calculations to analyze the low‐frequency properties of a single‐junction thermal converter using a modified low‐frequency model. A feature of the modified low‐frequency model is the incorporation of the heat capacity of the thermocouple and ceramic bead, which had been previously neglected. Since thermocouple and ceramic bead can increase the thermal inertia of the heater, they can modify the thermal time constant, which plays a crucial role at low frequencies. The calculated data using modified low‐frequency model for the AC–DC transfer differences correspond better to the experimental data. The difference of the AC–DC transfer difference between calculated and measured data is less than 10 µV/V down to 10 Hz. IEEJ Trans 2012. doi: 10.1002/tee.21739     

Transient stability output margin estimation based on the energy function method

In this paper, a new method of estimating the critical generation margin (CGM) in power systems is proposed based on transient stability diagnostics. The proposed method can directly compute the stability limit output for a given fault based on the transient energy function method (TEF). Since CGM can be directly obtained by the limit output using estimated P‐θ curves and is easy to understand, it is more useful than the conventional critical clearing time (CCT) of the energy function method. The proposed method can also estimate CGM as a negative value, which means instability in the present load profile, and so a negative CGM can be directly used as a restriction on generator output. The accuracy and fast solution ability of the proposed method are verified by applying it to a simple 3‐machine model and IEEJ EAST10‐machine standard model. Furthermore, the usefulness of the method for severity ranking of transient stability for various fault cases is discussed by using CGM. 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(3): 10–19, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ eej.21035     

FCE dedicates Yale power plant

In Connecticut, FuelCell Energy's high-efficiency Direct FuelCell® power plant installed at Yale University's Environmental Science Center (ESC) in New Haven has been dedicated. The combined heat and power unit is the first siting for FCE in its home state.     

Development and evaluation of a long‐range 300‐m leaky coaxial cable in the 2.4‐GHz band for IEEE 802.11 b/g wireless network access

In installing wireless access systems for indoor use using IEEE 802.11b/g‐complied 2.4‐GHz band wireless local area network (LAN) units, problems that arise include blind zones and interferences caused by radio waves transmitted by neighboring access point units. To solve these problems, the use of leaky coaxial cables (LCXs) is a promising method. However, commercially available flexible LCXs with small diameters for 2.4‐GHz wireless LAN were not long enough for use in tunnels, underground facilities, and so on, and the communication characteristics of LCXs long enough for these places using wireless LAN units have not been reported. We have developed a flexible 300‐m long LCX for the 2.4‐GHz band and IEEE 802.11b/g‐complied wireless LAN units with high sensitivity. We evaluated its performance with four cable configurations and confirmed that this LCX provides wireless connections over 300 m along the cable and over 20 m lateral to the cable in an open‐air environment. We also found the coverage could be extended by a method of cable‐to‐cable links. IEEJ Trans 2010 DOI: 10.1002/tee.20604