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As deregulation in the electric power industry has advanced in many countries, a spot market and a futures market for electric energy have already been formulated. In Japan, the foundation of a day-ahead spot market is scheduled for the 2005 fiscal year. This paper presents a method to evaluate the expected profit and risk for an electric power supplier considering both spot market and bilateral market. In this paper, the Vasicek model is used to represent the fluctuations in spot price and demand in a bilateral market, and additionally, Value at Risk (VaR) is used as a risk index. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 1–11, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20515 [ABSTRACT FROM AUTHOR]

The authors have proposed a Flexible, Reliable and Intelligent ENergy Delivery System (called “FRIENDS”), which is a new concept for a future power distribution system. One of the most important feature of FRIENDS is to be able to manage the reliability of power supply. In this paper, FRIENDS and a conventional distribution system are compared quantitatively as to supply reliability and cost through time sequential Monte Carlo simulation. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(4): 25–35, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20053 [ABSTRACT FROM AUTHOR]

Recently, the worldwide deregulation of the electric power industry is progressing. Further, it is expected that a many distributed generation facilities and energy storage systems will be installed at the end point of the power systems. Therefore, the future power system must be able to cope with these various qualities of power in the deregulated situation. The authors have proposed the FRIENDS (Flexible, Reliable, and Intelligent ENergy Delivery System) concept as a new distribution system that copes with a new framework of the electric power business in the near future. The most typical aspect of FRIENDS is the introduction of new equipment; Quality Control Centers (QCC) between distribution substations and customers. In this paper, the authors propose a concrete interior structure and investigate some control methods for realizing unbundling power quality supply and power conditioning using the proposed UPQC-type QCC. The effectiveness of the proposed method is confirmed through the instantaneous value analysis using PSCAD/EMTDC. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 26–38, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10243 [ABSTRACT FROM AUTHOR]

The authors have proposed FRIENDS—Flexible, Reliable and Intelligent Electrical eNergy Delivery System—as a future electric power distribution system. The most important idea of FRIENDS is to install new facilities called Quality Control Centers (QCCs) between the distribution substation and customers. By controlling QCCs appropriately, various purposes of FRIENDS can be achieved. It is indispensable to design the concrete interior structure of QCC in order to realize FRIENDS. This paper proposes the interior structure and control methods of QCC from the viewpoint of power conditioning functions by energy storage system in QCC. In this paper, it is assumed that SMES is used as the energy storage system in QCC. The proposed interior structure is based on the concept of UPS (Uninterruptable Power Supply). In this paper, SMES is installed in the DC side of UPS. Further, this paper proposes control methods of SMES and PWM converters. The proposed control methods are used to satisfy various purposes, such as load fluctuation compensation, load leveling, and cooperation with dispersed-type generator. Finally, the validity of these control methods is confirmed through transient analysis PSCAD/EMTDC. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(3): 20–28, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10056 [ABSTRACT FROM AUTHOR]

The authors have proposed the Flexible Reliable and Intelligent Electric eNergy Delivery System (FRIENDS) as a future electric power distribution system. In order to realize FRIENDS it is indispensable to design the concrete interior structure of the key facility, the Quality Control Center. This paper proposes an interior structure and control schemes for the Quality Control Center from the viewpoint of customized power quality service, which is one of the most important objectives of FRIENDS. The validity of the proposed structure and control schemes is confirmed through transient analysis using PSCAD/EMTDC. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(3): 45–52, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.1159 [ABSTRACT FROM AUTHOR]

In recent years, the introduction of superconducting magnetic energy storage systems (SMES) into a power system is drawing considerable research effort because of their high efficiency rate and large storage capacity characteristics. In this paper, the introduction of SMES into a power system and its effects on energy and on environmental issues are addressed. The analysis results show that the introduction of SMES can considerably cut down CO2 emissions without increasing the production cost if it substitutes for the operation of thermal plants during peak load period. However, to achieve this, nuclear plants are also needed for charging purposes. Thus, an algorithm to find the best generation mix, subject to CO2 emissions constraints and nuclear plant introduction constraints, is proposed. The inclusion of nuclear plant constraints increases the coal consumption, hence CO2 emissions. Nevertheless, in most of the analyzed cases, the introduction of SMES could attain important cost savings and environmental conservation. © 2000 Scripta Technica, Electr Eng Jpn, 131(1): 32–44, 2000 [ABSTRACT FROM AUTHOR]

Recently, utilities have been able to purchase the electric energy supplied from independent power producers (IPP) owing to deregulation in the electric industry. This paper evaluates the influence of IPP uncertainty on the utility and/or customer. In general, the production cost of energy supplied from IPPs is lower than that of a utility, although the IPP energy has more uncertainty compared with the utilities energy. This paper analyzes the effects caused by IPPs from the following three points: (i) By modeling a process of determining purchased power price as a negotiation model, the authors evaluate the influence of its uncertainty on a potentiality to introduce IPPs through variation of the purchased price. (ii) The authors evaluate the difference of power system reliability between a system under the deregulated environment with IPPs and a conventional system without IPPs. It is assumed that the system reliability is determined by minimizing the sum of supply cost and outage cost. (iii) Finally, the authors evaluate how the customer's various requirements about reliability influence the introduced amount of IPPs. © 2000 Scripta Technica, Electr Eng Jpn, 131(1): 56–67, 2000 [ABSTRACT FROM AUTHOR]

Theoretical study and phenomenal examination have been ongoing for many years; however, some electric power companies still have instantaneous power failure due to galloping. This study differs from others in that nonlinear three-dimensional simultaneous equations of conductor movement can be solved directly using numerical calculation. Fundamental characteristics of galloping can be ascertained by changing calculation parameters variously. This time, a method is used in which bundle conductors are changed equivalently to single conductor. It is also clarified that unstable domain becomes wider when rotational movement of conductor occurs. [ABSTRACT FROM AUTHOR]

Studies an alternating current excited synchronous machine analysis of the voltage characteristics. Steady state operating characteristics; Driving of the flywheel type energy storage device.

This paper discusses optimal planning problems for dispersed generating sources so as to provide a guideline for their introduction to power systems. First, a recursive method is developed from the viewpoint of supplying electric power only where solutions for one unit are superposed. The computational loads are decreased by selecting alternatives of buses based on the so-called penalty factor. However, for effective utilization of dispersed generating sources, it is indispensable to consider their thermal merits in addition to electric power. After applying the Kuhn-Tucker theory to the optimal dispatching problem including boiler fuel costs, thermal values of the dispersed generating units are evaluated quantitatively. Finally, the above-mentioned technique for the optimal planning basically is also the proposed algorithms are demonstrated using a real-scale model system. [ABSTRACT FROM AUTHOR]

To maintain power system security, the authors are developing an integrated security monitoring and control (ISMAC) system which consists of the three main functions: security monitoring, preventive control and emergency control. This paper focuses on the dynamic preventive control which deals with the transient stability assessment using the pattern recognition with two-dimensional feature space. Therefore, a preventive control strategy can be obtained rapidly. An index which represents the severity of the contingency quantitatively (security index) is defined by the distance from a linear decision surface which divides a feature plane into a stable and an unstable region. Further, this method has also the advantage that it is possible to consider the effect of the control devices or damping to some extent and specify the operator demand for stabilization flexibly. The effectiveness of the proposed method is ascertained through numerical examples for model power systems. [ABSTRACT FROM AUTHOR]

This paper presents a new method of simulating transient responses of multimachine power systems following a large disturbance. The conventional model used in the simulation is composed mainly of synchronous machine models in which the armature transients are neglected, and steady-state transmission sys- tem equations. This is because it is very difficult to treat the transmission system and the armature circuits of synchronous machines as differential equations. Naturally, the model cannot evaluate the effects of these neglected transients. The new method proposed herein uses the new synchronous machine model and the steady-state transmission system model. The former is obtained by modifying slightly the conventional armature-transient neglected model. Thus the resultant simulation model has almost the same structure as the conventional one. However, it can evaluate approximately the effects of armature transients on the dynamical behavior of the synchronous machines. For example, it can evaluate easily the angular backswing following a three-phase short-circuit fault. In addition, the new method can also estimate the maximum values of developed torque, induced voltage and armature current of synchronous machines at the moment when the disturbance occurred and when it was cleared. [ABSTRACT FROM AUTHOR]

Provides information on the development of an expert system that infers the possibility of snow accretion on transmission lines and indicates suitable deicing countermeasures. System outline; Configuration of the system; Detection of snow accretion on transmission lines from the power systems.

Proposes a faster technique for computing for the optimal operation problem of energy storage units. Basis of the method on the physical meaning of equivalent efficiency index H; Use of an iterative calculation method to determine the optimal operational mode of multiple units taking into account the energy loss of storage units.