Wind-Storage Oscillation Suppression via Two-Step Prediction
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Solution Overview
Problem
Existing methods for broadband oscillation suppression in wind-storage stations do not adequately consider the regulation cost and safety of energy storage apparatuses, leading to potential damage and instability during power grid failures.
Innovation Solution
A two-step prediction method is employed to optimize the distribution of wind turbine and energy storage apparatus currents, using a combination of wind turbine frequency and energy storage loss as regulation cost, and incorporating a phase-locked loop sub-model to determine optimal control variables, reducing the risk of oscillation and divergence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output of the energy storage apparatus is controlled only according to frequency deviation of wind turbine, then the broadband oscillation suppression is achieved, but the regulation cost of charging and discharging of the energy storage apparatus is not considered
Solution Approach 1:
The patent introduces a new parameter 'regulation cost' that combines wind turbine frequency deviation and energy storage charging/discharging loss. This transforms the control objective from pure frequency regulation to a cost-optimal control that considers both system stability and energy storage consumption.
Solution Approach 2:
The patent makes the control strategy dynamic by using two-step prediction to determine control variables at different time steps. The control variables are dynamically adjusted based on predicted frequency and regulation cost, rather than using a static frequency-deviation-only control approach.
2Device complexity
If a single-step prediction method is used for control, then the control process is simple, but the control system may experience oscillation and divergence
Solution Approach 1:
The patent segments the prediction process into two distinct steps: first prediction to obtain initial control variables, and second prediction to optimize control variables. This segmentation allows the system to achieve stable control by breaking down the complex prediction task into manageable stages.
Solution Approach 2:
The patent performs a preliminary prediction action in the first prediction step to obtain initial control variables and operation state quantities. These preliminary results are then used as inputs for the second prediction step, allowing the system to prepare and refine control actions before final implementation.
Data Source
AI summary
The invention offers a broadband oscillation suppression method and apparatus for wind-storage combinations. This method involves several steps: first, acquiring the operational state of a wind-storage station system at an initial moment. Next, different control variables and this operational state are input into a prediction model to identify two wind turbine frequencies and their corresponding operational states for a subsequent moment. Then, these control variables and the new operational states are used in the prediction model to derive wind turbine frequencies for a third moment. Finally, a control variable from the initial moment, linked to the wind turbine frequency with the lowest value function among the two frequencies at the third moment, is selected as the final control variable for managing the wind turbine and energy storage system. This method effectively reduces regulation costs during broadband oscillation suppression, enhancing the operational safety and stability of the wind-storage station.