Control methods for an energy storage system when wind power output deviates from grid code

Abstract

Because of the rapid growth of wind power, an electric grid company set the maximum change rate in a time window to share its fluctuation; this set maximum change rate in a time window is called the grid code. Large fluctuations of wind power may cause deviation from the grid code, but no studies discuss how to control an energy storage system (ESS) so that it quickly goes back to satisfying the grid code. The authors proposed three control methods for an ESS when the wind power output deviates; they are (1) 'restart' , (2) 'continuance without operation' , and (3) 'continuance with operation'. One year numerical simulations with two types of grid codes and two wind power output data have been performed to evaluate the methods. From the studies, control method (3) is found to be the best control method for an ESS to minimize capacity when the wind power output deviates from the grid code, and is verified by the numerical simulations. These results help to answer questions on how to reduce deviation time and ESS capacity using the control method when the wind power output deviates from the grid code.

Alerting to Rare Large-Scale Ramp Events in Wind Power Generation

“…Algorithm 3: SMOTE Implementation for Oversampling(.). (6) and add to S 1 h . end while Output: S 1 h .…”

“…Algorithm 3 shows the procedure of the SMOTE approach. The synthetic sample, Δp new t , was generated by the weighted average of the surrounding minority class samples as shown in (6) in Algorithm 3. Fig.…”

“…However, sudden and unexpected fluctuations in wind power generation (called ramp events) [2] could have a significant effect on the supply-demand balance in a power system under a high amount of penetration. To mitigate such effects, prediction technology is a valuable tool for planning operation of alternative generators [3], [4] or energy storage devices [5], [6], and decision making in a market [7], [8]. For example, if a sudden large-scale decline in wind power generation could be predicted in advance, the transmission system operators could start up cold reserve power plants, such as aged thermal power generators that are not usually in operation.…”

Scheduled operation of wind farm with a battery-energy-storage system considering ramp events

“…However, no formal definition is accepted [11]. This paper adopts the definition of ramp events proposed by M. Ito [12]: ramp event of WF output P WF t ð Þ is defined by a fluctuation greater than the maximum ramp rate ΔX of nominal power P r in time window ΔT from time T. That is, ramp event occurs when Equation (1) is satisfied at time T. The definition of ramp events is shown in Figure 2. ΔX is 0.3 pu and ΔT is 6 h.…”

Scheduled Operation of Wind Farm with Battery System Using Deep Reinforcement Learning

“…Ramp events threaten the reliable and economic operation of power systems [4]. In recent years, this phenomenon has been studied by working in the fields of analysis [4][5][6][7][8][9][10][11], forecasting [12], and control [13][14][15][16][17][18]. In terms of analytical studies, time series measured at offshore WFs in Horns Rev., Denmark, have been compared to a time series simulated based on the power fluctuation model presented in Reference [5].…”