Fluctuation Of Wind Power Output Research Articles

Spatial dependence in wind and optimal wind power allocation: A copula-based analysis

The investment decision on the placement of wind turbines is, neglecting legal formalities, mainly driven by the aim to maximize the expected annual energy production of single turbines. The result is a concentration of wind farms at locations with high average wind speed. While this strategy may be optimal for single investors maximizing their own return on investment, the resulting overall allocation of wind turbines may be unfavorable for energy suppliers and the economy because of large fluctuations in the overall wind power output. This paper investigates to what extent optimal allocation of wind farms in Germany can reduce these fluctuations. We analyze stochastic dependencies of wind speed for a large data set of German on- and offshore weather stations and find that these dependencies turn out to be highly nonlinear but constant over time. Using copula theory we determine the value at risk of energy production for given allocation sets of wind farms and derive optimal allocation plans. We find that the optimized allocation of wind farms may substantially stabilize the overall wind energy supply on daily as well as hourly frequency.

ＦＦＣ‐ＴＢＣ系統連系での蓄電池による連系線潮流変動抑制に関する基礎検討

In recent years, a lot of distributed generations such as photovoltaic and wind power generations are going to be installed in power systems. However, the fluctuation of these generator outputs affects the system frequency. Therefore, introduction of battery system to the power system has been considered in order to level the fluctuation of the total power output of the distributed generations. This research aims at suppressing the system frequency fluctuation and the tie line power flow deviation due to short-period fluctuation of wind power output within a certain range by cooperative control of LFC generators and battery system. It is assumed that a TBC based small control area with a large penetration of wind power plants is interconnected into a FFC based large control area. In this paper, the fluctuations of the system frequency and the tie line power flow are analyzed and LFC signal dispatching methods for effective control of the LFC generators and the battery system are proposed. Then, the required battery capacity for suppressing the tie line power deviation within a given level is evaluated.

Modelling the Impact of Wind Power Fluctuations on the Load following Capability of an Isolated Thermal Power System

Wind power is a clean and commercially competitive renewable energy technology that affords many utilities the opportunity to diversify and reduce their dependence on fossil fuels. However, the wind is also an intermittent energy source. Hence, many small and isolated utilities are concerned that, as the number and capacity of wind power plants increases, the resulting fluctuations in wind power output will impose excessive load following duty on their conventional units, leading to grid frequency control problems. This paper investigates the potential impact of wind energy development on the load following capability of a representative medium-sized, (2000 MW) thermal power system. Recorded system demand and wind power production data from the Northern Ireland system are statistically analysed, and the impact of expanded wind farm operation on net wind power and system demand fluctuations modelled and predicted for various time-scales of interest. The results demonstrate that the magnitudes of power output fluctuations from well-dispersed wind farms are small compared to system demand variations. Consequently, wind power expansion will not impose significant additional load following duty on the power system. Statistical analysis of net system demand and scaled wind farm time series data empirically verifies the validity of these findings.