VSC-HVDC Frequency Synchronization With Hydro Primary Regulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The mismatch in control speeds between VSC-HVDC Frequency Synchronization Control and hydro power primary frequency regulation systems leads to overcompensation and frequency fluctuations in the grid, necessitating a coordinated optimization method to balance their frequency response speeds.
Innovation Solution
A two-layer optimization model is employed to adjust the Kp and Ki parameters of the VSC-HVDC system and optimize the PID control parameters of the hydro power system, ensuring coordinated frequency regulation across different time scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If VSC-HVDC Frequency Synchronization Control operates at millisecond-scale control speed, then the response speed of frequency regulation is improved, but the hydro power primary frequency regulation system experiences overcompensation and induces new frequency fluctuations
Solution Approach 1:
The VSC-HVDC system performs preliminary frequency regulation action at millisecond scale to quickly suppress frequency deviations, then the hydro power system takes over for steady-state regulation, preventing overcompensation by coordinating the timing and magnitude of actions from both systems
Solution Approach 2:
The control parameters of the VSC-HVDC system are dynamically adjusted based on the operating state of the hydro power system. When the hydro system is actively regulating frequency, the VSC-HVDC control parameters are modified to reduce its调节 magnitude, preventing overcompensation while maintaining fast response capability when needed
2Stability of the object's composition
If asynchronous interconnection via DC links is implemented, then ultra-low-frequency oscillation issues are addressed, but the network scale of the sending-end grid is reduced and rotational inertia decreases
Solution Approach 1:
The VSC-HVDC system acts as an intermediary that provides virtual inertia and frequency regulation support to the sending-end grid without requiring physical rotational inertia. The control system simulates inertial response through power electronics, compensating for the reduced rotational inertia caused by asynchronous interconnection
3Stability of the object's composition
If governor parameters of large hydraulic turbines are adjusted to suppress ultra-low-frequency oscillations, then oscillation issues are resolved, but the primary frequency regulation capability of hydroelectric units is weakened
Solution Approach 1:
The frequency regulation function is segmented into two parts: the VSC-HVDC system handles ultra-low-frequency oscillation suppression through governor parameter adjustment, while the hydroelectric units maintain their primary frequency regulation capability through coordinated control. This segmentation allows both functions to operate independently without interfering with each other
Data Source
AI summary
A coordinated optimization method for VSC-HVDC Frequency Synchronization Control and primary frequency regulation of hydropower includes: obtaining optimal PI parameters of the VSC-HVDC Frequency Synchronization controller from a first layer output of a dual-layer optimization model for coordinated parameters of VSC-HVDC Frequency Synchronization and primary frequency regulation; and obtaining a target PID control parameters from a second layer output of the dual-layer optimization model. The coordinated optimization method further includes adjusting the optimal PI parameters of the synchronization controller based on the target selection range and updating the PID control parameters of the primary frequency regulation system of hydropower based on the target PID control parameters. This approach aims to address the challenge of balancing the frequency response speed between the VSC-HVDC synchronization system and the primary frequency regulation system of hydropower.