Power system control method using customers' energy storage systems and the verification of proposed method

Advanced energy storage systems have been widely applied to industries and are being installed at large buildings and factories to realize efficient energy usage. This paper presents a control method involving load frequency control and distribution network control (loss reduction control) using a part of customers' owned battery capacity. When 10% of total battery capacity of 100 MW in a network of 30‐GW generator capacities is used for load frequency control, a total of 1500‐MW generation units for load frequency control, at maximum, can be stopped without deterioration of power quality. In addition, when batteries are used for loss reduction in a distribution network, 2% of the loss on a summer day can be reduced. To realize both effects to their fullest, a novel integrated control algorithm is proposed and its economic effect is evaluated by numerical simulations. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(4): 11–20, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20704     

Damage repair in CMSX-4 alloy without fatigue life reduction penalty

The microstructural changes in a single-crystal Ni-base superalloy, CMSX-4, that might occur during the processes of repair and recoating of hot section components for advanced gas turbines were studied. It is shown that the cellular γ/γ′ microstructure is formed when the material is subjected to local plastic straining, followed by the reheat treatments during the course of damage recovery. The formation of cellular microstructure in the material led to the remarkably reduced fatigue strength. In order to reduce or prevent the preceding undesirable effect resulting from cellular microstructure, a new method based on applying overlay coating technique was developed. The method is based on an idea that the alloying elements that are depleted in base alloys could be supplemented via the overlay coating. An X alloy, which contains grain boundary strengthening elements, was selected and coated on the CMSX-4 with the cellular microstructure by low-pressure plasma spraying. The fatigue tests on the coated CMSX-4 specimens demonstrated the effectiveness of the method. The observations of the crack initiation site, the fatigue fracture mode, the crack density in the cellular transformed area, and the crack propagation morphologies near the prior interface strongly supported the validity of this approach. The method is expected to build a road to a so-called damage cure (or recovery) coating.     

ESR study on radical polymerization of styrene

Summary Propagation rate constant (k_p) for styrene was evaluated at different chain lengths of the polymer radical based on the steady-state concentration of the polymer radical determined by means of ESR spectroscopy at 70°C. Over a range of degree of polymerization of the polymer radical from 40 to 410, the value of k_p, 480±10 L/mol·s, remained constant. A considerable increase in viscosity of the polymerization mixture did not affect this value.     

Removal of Cr(VI) from aqueous solution by London plane leaves

The effect of initial metal concentration, contact time and solution temperature on the removal of Cr(VI) from solution by waste London plane leaves, generated by the pruning of street trees, was investigated in batch mode conditions. The removal of Cr(VI) was highly concentration‐dependent and mainly governed by physico‐chemical adsorption under the weak acidic conditions studied. The equilibrium data fit well in the Langmuir isotherm model. The Langmuir constants were calculated at different temperatures and both the adsorption capacity and adsorption intensity increased with rising temperature. The endothermic nature of the Cr(VI) adsorption was confirmed by the thermodynamic parameters. The study has shown that the waste leaves can be used as an effective adsorbent for removal of Cr(VI) from wastewater. Copyright © 2003 Society of Chemical Industry     

Cutting plane methods for Lagrangian relaxation‐based unit commitment algorithm

In this paper, we study cutting plane methods for a Lagrangian relaxation‐based unit commitment algorithm. In the algorithm, nondifferentiable optimization methods can be applied to optimize the dual function, and a subgradient method which needs parameter tuning and has some drawbacks such as computational inefficiency and oscillating behavior is commonly used. The cutting plane method and the central cutting plane method are applied to the algorithm and implemented using reoptimization techniques. A numerical example shows that both methods are accelerated by the reoptimization techniques and have good convergence without parameter tuning. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(3): 17–29, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10066     

Electrostatic Field Variation in the Atmosphere Induced by Earth Potential Difference Variation During Seismic Wave Propagation

To clarify the relationship between earthquakes and electrical phenomena, signals of three parameters were observed continuously at Sennan in Akita Prefecture, Japan: ground acceleration (GAC), earth potential difference (EPD), and electrostatic field in the atmosphere (EFA). A large metal plate was used as an electrostatic antenna to observe EFA variation. For this paper, we used the digital natural observation (D-NOB) method as a signal processing technique and found clear EPD and EFA waveforms during seismic wave propagation. Our observation and examination results show that GAC causes EPD variation. Subsequently, the EPD variation induces EFA variation     

Advanced evaluation of thermal ratchetting of FBR components

A new prediction method for the thermal ratchetting of a cylinder subjected to an axially moving temperature distribution is proposed in this paper. This ratchetting is quite different from the conventional Bree-type ratchetting, and an advanced evaluation method has been required in the structural design of FBR components. The proposed method considers the work hardening of actual materials for FBR components. Firstly the basic scheme of the prediction method is shown, and secondly the application procedure to the actual design is shown. Predicted results by using this method coincide well with experimental results, when compared with the case by using the previous method.     

Estimation method of frequency bias using normal operating data

A technique of calculating the frequency bias of an electric power system from frequency fluctuation data and total output power is described. An evaluation method for testing the calculations by the new method is developed. The results are in good agreement with estimates based on generator speed regulation but the method gives an excessively high figure for the load frequency bias.     

Emissivity of chlorinated polyethylene

The emissivity of chlorinated polyethylene containing varying amounts of combined chlorine has been investigated. It was found that the emissivity of these compounds increases significantly with increase in chlorination.