Fumitoshi Nomiyama

Optimal operation scheduling of pumped storage hydro power plant in power system with a large penetration of photovoltaic generation using genetic algorithm

In recent years, a substantial amount of photovoltaic (PV) generations have been installed in Japanese power systems. However, the power output from the PV is random and intermittent in nature. Therefore, the PV generation poses many challenges to system operation. To evaluate impacts of the behavior of PV on power supply reliability, we have developed power supply reliability evaluation model considering a large integration of PV generation into power system. As a result, the power supply reliability is getting worse as the PV penetration increases. To mitigate this issue, we have proposed that pumped storage hydro power plant (PSHPP) is used to improve the reliability. However, its operation may increase the power system operational cost. In this paper a new method for scheduling the effective operating pattern for PSHPP that makes it possible to improve both reliability and economy is presented.

Impact of operational scheduling of pumped storage power plant considering excess energy and reduction of fuel cost on power supply reliability in a power system with a large penetration of photovoltaic generations

In recent years, a substantial amount of photovoltaic (PV) generations have been installed in power systems. However, the power output from the PV is random and intermittent in nature. As a result, the PV generation poses many challenges to system operation. PV generates electricity only in the daytime regardless of power demand. When the daytime power demand is small and PV generation is large, severe imbalance in power demand and supply may occur in the power systems. To mitigate the power imbalance, we propose that pumped storage power plant (PSPP) is used to solve the problem. Usually the PSPP is operated in generator mode in the daytime and in pump mode in the nighttime. However if the power imbalances due to the installation of PV is also to be handled by PSPP then the operating patterns of PSPP have to be modified. Such modification in the operating pattern of PSPP could introduce reliability concerns related to the operation of power systems. Therefore we need to study impact of the operational patterns of PSPP to solve the problems associated with excess power produced by PV on the power supply reliability. In this paper a new method for the effective operating pattern for PSPP taking into consideration the fuel cost and the impact of excess power on the reliability of system operation is presented.

A study on global solar radiation forecasting using weather forecast data

A set of three methods are proposed for forecasting amounts of global solar radiation. The forecasts are used to predict the output power of photovoltaic systems installed in power systems and control the output of other generators to meet the electricity demand. The methods forecast two-day-ahead, one-day-ahead and three-hour-ahead global solar radiation, respectively, based on weather information using descriptive statistics, factor analysis and binary trees. The main focus is on estimation of the anticipated variations in the forecasts, finding relevant input variables or signal components, and dealing with the nonlinearity of the relationship between the global solar radiation and the input variables. The methods have been tested on the meteorological and global solar radiation data obtained at an observation site, and the results show that they are promising to be used to keep the balance between demand and supply of electric power in the near future power systems with a large number of photovoltaic systems installed.

Impact of Operational Scheduling of Pumped Storage Power Plant Considering Excess Power on Power Supply Reliability in a Power System with a Large Penetration of Photovoltaic Generations

In recent years, a substantial amount of photovoltaic (PV) generations have been installed in Japanese power systems. However, the power output from the PV is random and intermittent in nature. As is known, the PV generation poses many challenges to the power system operation. To evaluate impact of the behavior of PV, we developed power supply reliability evaluation model considering a large penetration of PV generation into the power system. As a result, power supply reliability is getting worse as the PV penetration increases. To mitigate these issues, we proposed that pumped storage power plant (PSPP) is used to improve the reliability. This paper presents a fundamental study on the impact of the operation scheduling of PSPP taking into account the excess power caused by PV generations on the power supply reliability, which is evaluated by Monte Carlo simulation.

Optimal Operation Scheduling of Pumped Storage Hydro Power Plant and Thermal Power Plants in Power System with a Large Penetration of Photovoltaic Generations

In recent years, a substantial amount of photovoltaic (PV) generations have been installed in power systems. However, the power output from the PV is random and intermittent in nature. Therefore, the PV generation poses many challenges to the power system operation. To evaluate the impact of the behavior of PV on power supply reliability, we have developed a power supply reliability evaluation model considering a large integration of PV generation into power system. As a result, the power supply reliability is getting worse as the PV penetration level increases. To solve this issue, we have proposed that pumped storage hydro power plant (PSHPP) is used effectively to improve the reliability. In this paper a cooperative scheduling method for the PSHPP and thermal power plants that makes it possible to improve both reliability and economy is presented. being considered as a solution in most situations. This paper proposes an effective use of Pumped Storage Hydro Power Plant (PSHPP). PSHPP is installed originally for hot reserve of the power system and load leveling. The energy is stored in the form of water pumped up from a lower reservoir to an upper reservoir. The PSHPP is usually operated as a generator in the daytime and a pump in the nighttime. A new operation scheduling of PSHPP is proposed to solve the problem in this paper. It will be operated with the proposed pattern solving the surplus power problem caused by the PV generation. The authors have already proposed how the PSHPP operation pattern is changed effectively to improve the power system reliability in case of a large integration of PV into the power system (1). However, the scheduling method for obtaining the optimal PSHPP operation pattern that makes it possible to improve both reliability and economy has not been developed yet. In this paper, we propose a new method for planning PSHPP operation pattern considering the surplus power problem, power supply reliability and fuel cost reduction, which is represented by pareto optimal solutions. The power supply reliability and the fuel cost are estimated for each PSHPP operation plan by using Monte Carlo simulation.

A Study on Synchronous Stability Analysis of Power System with a Large Amount of PVs

AbstractTo solve the energy and environmental issues, it is planned that a large amount of photovoltaics (PVs) are introduced in Japan. However, because the characteristic of PV output is different from that of conventional generators, it is possible that the synchronous stability changes due to a large amount of PVs. Additionally, supposing that some generators are stopped when PV output becomes large, decrease of inertia constant and change of power flow are also important factors for synchronous stability. Hence, in this paper, the synchronous stability of power system with a large amount of PVs is studied considering both the voltage characteristic of PV output and the change of system operation such as unit commitment. Specifically, the stability is evaluated from a viewpoint of critical clearing time (CCT) based on both the accelerating and decelerating energy in P-δ curve. IEEJ-WEST10 model system is utilized as a simulation model.