Renewable Plant Power Control Using EDSCR for Weak Grid Stability
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Solution Overview
Problem
Renewable energy power plants connected to weak AC power grids face instability due to high voltage sensitivity, leading to temporary curtailment of active power and significant revenue losses when grid strength falls below a minimum threshold, prompting intervention from the Transmission System Operator.
Innovation Solution
A method that involves receiving measurement signals from renewable energy power plants to determine dynamic short circuit ratios (DSCR) and equivalent DSCR at collection points, allowing for real-time control of active power set points to maintain grid stability and avoid TSO intervention, thereby stabilizing the grid and maximizing revenue generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Transmission System Operator curtails power from the wind park to avoid sustained system instability, then grid stability is improved, but revenue generation is significantly reduced
Solution Approach 1:
The system performs preliminary actions by estimating the dynamic short circuit ratio (DSCR) and equivalent DSCR (EDSCR) before TSO intervention occurs. By continuously monitoring grid strength parameters and predicting stability issues in advance, the system takes proactive measures to adjust power output, thereby maintaining grid stability while minimizing revenue loss through avoided curtailment.
Solution Approach 2:
The system implements feedback mechanisms by continuously measuring power characteristics at the point of interconnection, calculating DSCR and EDSCR values, and using this information to dynamically control active power set points. This closed-loop feedback enables the system to respond to changing grid conditions in real-time, optimizing the balance between stability and revenue generation.
2Productivity
If the power plant operates at full capacity during temporary grid strength reduction, then revenue generation is maximized, but grid instability occurs leading to TSO intervention
Solution Approach 1:
The system changes operational parameters by dynamically adjusting active power set points based on real-time estimates of DSCR and EDSCR. When grid strength parameters indicate potential instability, the system modifies power output levels accordingly, enabling full operation during stable conditions while preventing instability during weak grid periods, thus optimizing both revenue and reliability.
3Device complexity
If the system uses DSCR at the point of interconnection for control, then grid strength monitoring is simplified, but accurate control at the collection point is compromised
Solution Approach 1:
The system introduces an intermediary parameter, the equivalent DSCR (EDSCR), which bridges the measurement at the point of interconnection and the control needs at the collection point. By transforming the DSCR measurement through the impedance characteristics of the connecting network, the system accurately represents grid strength at the collection point without requiring direct measurement there, thus maintaining simplicity while achieving precision.
Data Source
AI summary
Operating a renewable energy power plant connected to a power network at a point of interconnection. The plant includes: one or more renewable energy generators connected to a collection point of the renewable energy power plant, and a connecting network connecting the collection point to the point of interconnection. One method includes: receiving one or more measurement signals indicative of measured power characteristics of the renewable energy power plant at the point of interconnection; determining a dynamic short circuit ratio (DSCR) at the point of interconnection based on the one or more measurement signals; determining an equivalent dynamic short circuit ratio (EDSCR) at the collection point based on the determined DSCR at the point of interconnection and one or more components of an impedance of the connecting network; and controlling the one or more renewable energy generators by determining and dispatching active power set points based on the determined EDSCR.