Deregulation of the electric utilities has been progressing. Even under the deregulation, the reliability should be the most important problem of power systems. However, according to the deregulation, operation and scheduling of power systems are changing and new techniques to analyze power systems are introducing. To evaluate reliability of power systems, adequacy and security are well employed recently. This paper presents the new analyzing technique which will be realized in near future from the viewpoint of adequacy and security. First, simulation tool to evaluate adequacy is described. As an example of this tool, MARS and other methods are mentioned. Next, to evaluate the security, security constrained unit commitment (SCUC) and security constrained optimal power flow (SCOPF) are mentioned. Finally, some topics concerning ancillary service are described.

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This paper proposes a fast computation method for Available Transfer Capability (ATC) with respect to thermal and voltage magnitude limits. In the paper, ATC is formulated as an optimization problem. In order to obtain the efficiency for the N-1 outage contingency calculations, linear sensitivity methods are applied for screening and ranking all contingency selections with respect to the thermal and voltage magnitude limits margin to identify the severest case. In addition, homotopy functions are used for the generator QV constrains to reduce the maximum error of the linear estimation. Then, the Primal-Dual Interior Point Method (PDIPM) is used to solve the optimization problem for the severest case only, in which the solutions of ATC can be obtained efficiently. The effectiveness of the proposed method is demonstrated through IEEE 30, 57, 118-bus systems.

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Since the FY2003, the demonstration site Josai-no-mori including over 500 residences with PV system has been under construction at the Ota City, Gunma prefecture in Japan. It is important to clear the safety of islanding protection. However, it is very difficult to verify the islanding phenomena including many PV systems on the actual utility grid, where the people are leading life actually. Therefore, it becomes important to develop a technique employing simulation analysis for the safety evaluation.
Purpose of our study is to clear the details of dangerous islanding phenomena and the effects of various protection methods under clustered installation of over 500 PV systems within a partial area of utility grid. To solve these problems, a new analysis method has been developed, that is based on the CRIEPI's Power system Analysis Tools (CPAT) technology implemented by CRIEPI, so called “Y-method".
As a noteworthy result, it has been confirmed that the new simulation method has a capability to expand to the large-scale clustered installation model including 500 PV systems on utility grid. The validity of simulation analysis has been verified by comparing with preliminary indoor tests. In addition, it has been clarified that the combination of passive and active protection methods is very effective to avoid the islanding phenomena.

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In recent years, deregulation of the electric industry in the world aims at creating competitive markets to trade electricity. For deregulated transmission networks, one of the major consequences of the nondiscriminatory open-access requirement is a substantial increase of power transfers. Congestion management of deregulated transmission networks is very important to accomplish always nondiscriminative network access. In this paper, the authors propose a congestion management approach by using Thyristor Controlled Series Capacitor (TCSC) in order to maximize transmission margin and minimize transmission loss without changing contracted power under constraints such as thermal, voltage, and stability limits. In the proposed approach, power flow through transmission lines can be flexibly controlled without changing contracted power by determining firing angle of TCSC. In order to check the validity of the proposed congestion management approach, numerical results are shown for 6 bus system model. Simulation results show effectiveness of the proposed congestion management approach by using TCSC, when congestion occurs at a transmission line in the system model.

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Recently, deregulation of electric power industry became popular in world wide. In Japan, under partially de-regulated power industry, transmission system is operated by a power company. Although operator of the transmission system tries to determine permissions to connect generators owned by IPPs (Independent Power Producer) and PPSs (Power Producer and Supplier) through considering power congestions for typical power flow conditions, operators inevitably face the congestions of the power system when some generators are in fault conditions. In such a case, operators must resolve the congestions re-scheduling generators owned by their own companies and those owned by IPPs and PPSs. This problem can be solved though a Security Constrained Unit Commitment (SCUC). This paper proposes a new solution algorithm for SCUC by using the Lagrangean decomposition. The method decomposes the SCUC problem into two sub-problems. One sub-problem is a decision problem which determines an operational power flow or generation schedules in which security constraints are taken into account. The other is the unit commitment problem with minimum up/down time constraints for all the units. Several numerical examples are shown to demonstrate the algorithm.

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Fuel Cell (FC) that works under the influence of chemical changes can not respond rapidly to sudden load changes. To overcome it, one normal method is to enlarge the capacity of FC, which results in the efficiency decreasing. As another effective method, an electric power storage device is used. Therefore, Electric Double Layer Capacitor (EDLC) that is not influenced by chemical reactions is paid attention. The purpose of this research is to overcome the problem of the load change by using the EDLC connected to the FC. The authors examined the load changes in two kinds of power supply modes. In one case, the power was supplied by FC only, while in another case, FC and EDLC connected in parallel were used for power supply. The results obtained from the comparison between two cases show that the output power of FC can be reduced by using EDLC. As a result, the power supply mode of the parallel connection of FC and EDLC can effectively solve the problem of load change.

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In this letter, we propose a preprocessing method for Multi Layer Perceptron (MLP) forecasting method using Independent Component Analysis (ICA). We use the ability of ICA capturing underlying structures in time-series data, and apply ICA to MLP forecasting problem. Specifically, we try to improve accuracy of forecasting by dimension reduction of input variables using Complexity Pursuit which is one of the ICA algorithms based on spatial and temporal structures in the data.

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