本記事に「抄録」はありません。

抄録全体を表示

This paper proposes new methods for evaluating foreign investment in power plants under market uncertainty using a real options approach. We suppose a thermal power plant project in a deregulated electricity market. One of our proposed methods is that we calculate the cash flow generated by the project in a reference year using actual market data to incorporate periodic characteristics of energy prices into a yearly cash flow model. We make the stochastic yearly cash flow model with the initial value which is the cash flow in the reference year, and certain trend and volatility. Then we calculate the real options value (ROV) of the project which has abandonment options using the yearly cash flow model. Another our proposed method is that we evaluate foreign currency/domestic currency exchange rate risk by representing ROV in foreign currency as yearly pay off and exchanging it to ROV in domestic currency using a stochastic exchange rate model. We analyze the effect of the heat rate and operation and maintenance costs of the power plant on ROV, and evaluate exchange rate risk through numerical examples. Our proposed method will be useful for the risk management of foreign investment in power plants.

抄録全体を表示

Large penetration of PV may affect transient stability when fault occurs on a transmission line. Classical model for a synchronous generator, a constant current source model for PV and a constant impedance model for load are applied to the one-machine-to-infinite-bus model. The critical clearing time is calculated by using equal area criterion and Y method simulation. As a result, a case with larger PV penetration has longer CCT than the case without PV penetration and this result does not depend on the reduction of synchronous generator capacity according to PV output.

抄録全体を表示

An approximate method to calculate voltage in three-phase primary distribution feeder has been proposed. Generally, nonlinear simultaneous equations have been solved to calculate the voltage in power system since the dependence of electrical equipment on voltage is represented by exponential model such as constant power load, constant current load and constant impedance load. The nonlinear simultaneous equations were transformed to linear simultaneous equations by the proposed method. As a result, the proposed method can calculate the voltage without convergence calculations. It was found that the approximate value of voltage in the three-phase primary distribution feeder is in good agreement with the exact value.

抄録全体を表示

In Japan, from the viewpoints of global warming countermeasures and energy security, it is expected to establish a smart grid as a power system into which a large amount of generation from renewable energy sources such as wind power generation and photovoltaic generation can be installed. Measures for the power system stability and reliability are necessary because a large integration of these renewable energy sources causes some problems in power systems, e.g. frequency fluctuation and distribution voltage rise, and Battery Energy Storage System (BESS) is one of effective solutions to these problems. Due to a high cost of the BESS, our research group has studied an application of controllable loads such as Heat Pump Water Heater (HPWH) and Electric Vehicle (EV) to the power system control for reduction of the required capacity of BESS. This paper proposes a new coordinated Load Frequency Control (LFC) method for the conventional power plants, the BESS, the HPWHs, and the EVs. The performance of the proposed LFC method is evaluated by the numerical simulations conducted on a power system model with a large integration of wind power generation and photovoltaic generation.

抄録全体を表示

This paper investigates the impact of an extensive introduction of electric vehicle (EV) and plug-in hybrid vehicle (PHEV) into global energy system towards 2050. The significant growth of automobile ownership in emerging countries is likely to increase the world oil demand and the associated carbon dioxide emissions. In order to address these energy security and environmental concerns, the deployment of clean energy vehicles, such as EV and PHEV, are expected to play a crucial role due to its high fuel efficiency. On these backgrounds, we develop both global energy system model and world vehicle penetration model, which are able to explicitly analyze the impact of EV introduction into seasonal daily electric load curve considering its specific electricity charging profile to 2050. Simulation results confirm that EV deployment contributes to energy conservation, because oil demand reduction outstrips the growth in its electricity demand and the associated fuel input into power generation mix. Concerning carbon dioxide abatement, the magnitude of the impact relies on the carbon-intensity of power generation mix. If the intensity is low enough to make sure the carbon mitigation effect by EV fuel saving, the emissions reduction is well ensured. It should be noted, however, that, in the regions with high carbon intensity in power generation mix, carbon emissions per mileage of EV is almost equivalent to that of efficient gasoline vehicle like hybrid vehicle and PHEV is slightly higher than hybrid vehicle.

抄録全体を表示

An emergency control has been applied to power systems to avoid cascading outages by making the best use of existing equipment under severe fault conditions. Battery energy storage system (BESS) is one of the attractive equipment for the emergency control according to its growing installed capacity in the current grid. This paper investigates an effective use of BESS for transient stability improvement, and proposes a novel control scheme using wide-area information. The proposed control scheme adopts two stability indices, the energy function and rotor speed of the critical machine, to make it applicable to multi-machine power systems. Besides, it can control active and reactive power injection of the BESS coordinately to make the best use of its converter capacity for the stability enhancement. Digital simulations are conducted on the 32-machine meshed system with multiple BESSs. The results demonstrate that the BESSs controlled by the proposed method can improve the first swing stability and the system damping, and it is made clear how they improve the transient stability of the multi-machine power system. In addition, an impact of the reactive power control on the bus voltages around the installation sites is investigated to discuss a preferable way of their installation.

抄録全体を表示

Nowadays, a large integration of photovoltaic and wind power generations causes an imbalance between supply and demand in power systems because their outputs are intermittent. To solve the mentioned problem, Vehicle-to-Grid (V2G), which is one of the smart grid technologies, has gained much attention. Under the concept of V2G, batteries of Electric Vehicles (EVs) can be used as Battery Storage Energy Systems (BESS) in the power system. In this paper, we are developing a new Load Frequency Control (LFC) method using EVs, which is named the State Of Charge (SOC) synchronization control. In the proposal control method, a number of EVs in the power system can be considered as one large-capacity BESS. Moreover, the EVs can be plugged-in/out whenever the users want to and can store the sufficient energy for the next trip at plug-out.

抄録全体を表示

In this paper, we present the results of the validation of solar radiation estimation using sunshine duration information of the Automated Meteorological Data Acquisition System (AMeDAS) Data provided by the Japan Meteorological Agency. The validation was carried out using insolation data of 20 points in the Hokuriku region. Because of the difference of the position between AMeDAS sites and insolation measurement points, the weighting that is inversely proportional to the distance was applied. Accuracy was evaluated by correlation coefficients and root mean square error. The correlation coefficient was 0.84-0.96, if a single point insolation was estimated. And the accuracy of about 0.98 was obtained when the average of 20 points in the Hokuriku region was estimated. Global solar radiation calculation method using AMeDAS is considered to have sufficient practical accuracy.

抄録全体を表示

Although it is well known that an adequate dynamic load model in power system is indispensable for stability analyses especially when renewable energies highly penetrate nearby loads, researches on dynamic load model are quite poor even in the beginning of a low-carbon era. The authors have represented an actual dynamic load as parallel of an induction motor (IM), a resistor and a capacitor behind fixed impedance, and identified parameters of the dynamic load model using measured data during and after voltage sags. The results were already reported. Since some improvements on the identification were made, the newest results are reported here. The most important three parameters are identified ; IM ratio is 50%, IM inertia is 0.5 sec., and IM loading is 50% at peak demand when power system stability becomes the worst.

抄録全体を表示

To reduce the energy capacity and power capacity of energy storage systems (ESSs) which is necessary to compensate power fluctuation in a power grid, the control of power that is used by electrical appliances on the demand side is considered. In this paper, the use of heat pump air conditioner for power fluctuation compensation is focused. The basic power consumption characteristics and processed heat characteristics of heat pump air conditioner which is measured by experiment using real machine is reported. Based on the measured characteristics, a simple model of heat pump is proposed. Using this heat pump model, simulations were carried out to analyse the amount of ESS's capacity that can be reduced by controlling the heat pump to compensate power fluctuations.

抄録全体を表示

In recent years, a substantial amount of photovoltaic (PV) generations have been installed in power systems. However, the power output from the PVs is random and intermittent in nature. Therefore, the PV generations pose many challenges to the power system operation. To solve these issues, we propose that pumped storage hydro power plant (PSHPP) is used effectively. In this paper, a new method for scheduling effective operating patterns for PSHPP that make it possible to improve both reliability and economy is presented.

抄録全体を表示

The power market is to be in highly competitive environment because of power deregulation. The electric power companies have raised business efficiency to reduce the number of employee and centralize the business establishments. Furthermore, an installation of photovoltaic generation (PV) will increase because of energy policy. However, electric power companies must maintain power supply reliability. Therefore, to reinforce the reliability in distribution systems is one of significant problem. In this paper, we propose an optimal placement of distribution section switches to maintain the power supply reliability under such a situation and exhibit the simulation result in the original distribution system using genetic algorithm.

抄録全体を表示

The proportion of the lightning outages in all outages on Japanese 6.6kV distribution lines is high with approximately 20 percent, and then lightning protections are very important for supply reliability of 6.6kV lines. It is effective for the lightning performance to apply countermeasures in order of the area where a large number of the lightning outages occur. Winter lightning occurs in Hokuriku area, therefore it is also important to understand the seasonal characteristics of the lightning outages. In summer 70 percent of the lightning outages on distribution lines in Hokuriku area were due to sparkover, such as power wire breakings and failures of pole-mounted transformers. However, in winter almost half of lightning-damaged equipments were surge arrester failures. The number of the lightning outages per lightning strokes detected by the lightning location system (LLS) in winter was 4.4 times larger than that in summer. The authors have presumed the occurrence of lightning outages from lightning stroke density, 50% value of lightning current and installation rate of lightning protection equipments and overhead ground wire by multiple regression analysis. The presumed results suggest the local difference in the lightning outages.

抄録全体を表示

Recently, more and more unstable renewable energy based generations such as photovoltaic generations and wind turbine generations have been installed into power systems. This paper focuses a small island power system operation and proposes a novel control method of power consumption of a seawater desalination plant as a controllable load in order to secure more regulating capacity of the power system considering the customer's convenience of the desalination plant. Through a frequency analysis simulation, fuel cost can be reduced and system frequency fluctuation can be suppressed for the proposed control method of seawater desalination plant.

抄録全体を表示

This paper proposes an optimal allocation of FACTS devices for maximizing Loadability with hybrid cording EPSO (Evolutionary Particle Swarm Optimization). Loadability shows the maximum load that can be supplied in power network without the violation of thermal, voltage limits, etc. It is important to study it due to the system planning and operating. An allocation of FACTS devices is one of the attractive ways to increase Loadability. However, it is not easy to determine the optimal location and the optimal variable output of FACTS devices. The former is expressed in discrete number while the latter is represented in continuous one. As a result, the problem to be solved results in a nonlinear mixed integer problem that is very hard to solve. In addition, the use of MCS (Monte Carlo Simulation) to consider the uncertainty such as variable generations leads an increase in computational time. This paper proposes a hybrid cording EPSO that is combination of discrete and continuous EPSO to reduce the computational time and to improve accuracy. The proposed method is successfully applied to a sample system.

抄録全体を表示

This paper proposes a new method for probabilistic reliability evaluation with Multi-objective meta-heuristics (MOMH) in consideration of solution diversity. Recently, the power networks increase the degree of the uncertainties due to the new environment of power network liberations and the emergence of the renewable energy, etc. The importance of the probabilistic reliability assessment of electric power systems has been recognized. Probabilistic reliability evaluation has been broadly used for power system operation and planning due to the capability of considering the various system uncertainties. MOMH is useful for evaluating a set of the Pareto solutions systematically. The effectiveness of the proposed method is successfully demonstrated to the IEEE Reliability Test System (IEEE-RTS).

抄録全体を表示

The 22^nd Power and Energy Society Annual Conference was held on August 30 - September 1, 2011 at University of Fukui. The total number of technical papers was 346, and technical sessions were 43 (42 oral sessions and 1 poster session). An invited lecture, a panel discussion, technical exhibitions and two technical tours were organized. All events were very well attended and the final enrollment attained to 888 registrations. The conference was successfully closed by the great contribution of all participants. The outline of the conference is reported in this article.

抄録全体を表示