Energy Storage Transient Control for HVDC Commutation Failures
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Solution Overview
Problem
In high voltage direct current (HVDC) transmission systems, commutation failures lead to rapid DC voltage drops and sharp increases in DC current, causing significant disruptions and potentially resulting in multiple converter station failures and DC lock-up, which threatens the safety of AC/DC hybrid power grids, especially in 'strong DC and weak AC' power grids like those in China.
Innovation Solution
An Energy Storage Transient Power Coordinated Control Method is implemented, which continuously detects DC current, AC bus voltage, and arc quenching angle to control energy storage power stations to enter transient control mode, determining active and reactive power output instructions based on these parameters to provide timely and coordinated power support, thereby reducing subsequent commutation failures and improving grid recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If energy storage power station provides transient power support after commutation failure, then the number of subsequent commutation failures is reduced, but the device complexity increases
Solution Approach 1:
The energy storage power station is pre-configured and ready to provide transient power support before commutation failures occur. The control system continuously monitors DC current, AC bus voltage, and arc quenching angle, and automatically activates the energy storage device when failure conditions are detected, providing immediate power support without requiring complex real-time decision-making algorithms
Solution Approach 2:
The control system implements continuous feedback monitoring of DC current, AC bus voltage, and arc quenching angle to detect commutation failure conditions. Based on the feedback signals, the energy storage power station automatically adjusts its power output to provide transient support, creating a closed-loop control system that improves reliability through responsive action rather than through complex predictive algorithms
2Speed
If energy storage power station responds quickly to commutation failure, then grid recovery ability is improved, but the measurement precision requirements increase
Solution Approach 1:
The control system is pre-programmed with threshold values for DC current, AC bus voltage, and arc quenching angle that trigger energy storage activation. This preliminary setup allows the system to respond quickly by comparing real-time measurements against predetermined thresholds, rather than requiring complex real-time analysis that would demand higher measurement precision
Solution Approach 2:
The control strategy divides the monitoring parameters into distinct segments: DC current monitoring, AC bus voltage monitoring, and arc quenching angle monitoring. Each parameter is independently measured and compared against its own threshold, allowing the system to achieve fast response through simple threshold comparisons rather than requiring highly precise integrated measurement of all parameters simultaneously
Data Source
AI summary
The invention discloses an energy storage transient power coordinated control method for restraining subsequent commutation failures, which includes: detecting DC current, AC bus voltage and arc quenching angle on the inverter side; Controlling the energy storage power station to enter the transient control mode when the DC current is greater than the first current threshold or the AC bus voltage is less than the voltage threshold or the arc quenching angle is less than the first arc quenching angle threshold. By detecting the DC current and arc quenching angle on the inverter side, the active power output time instruction and reactive power output time instruction are determined respectively. The active power output amplitude instruction is determined by detecting the AC bus voltage, and the reactive power output amplitude instruction is determined by using the constraint of the total energy storage capacity.