HVDC Voltage Regulation Switching for No-Load Stability
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Solution Overview
Problem
High voltage direct current (HVDC) systems face instability during no-load conditions and voltage overshoot during load transients, leading to generator terminal voltage instability and potential overvoltage faults, which existing systems fail to adequately address.
Innovation Solution
A system that includes a generator, a power converter, and a voltage regulator with a regulator selector that switches between AC and DC voltage regulation based on monitored AC and HVDC bus voltages and currents, stabilizing the generator terminal voltage and improving voltage transients by selecting the appropriate point of regulation (POR) and utilizing a dynamic break resistor (DBR) to control overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If DC voltage regulation is used during no-load conditions, then generator terminal voltage becomes unstable with oscillations, but switching to AC voltage regulation stabilizes the voltage
Solution Approach 1:
The system dynamically switches between DC voltage regulation and AC voltage regulation based on load conditions. The regulator selector monitors the load and automatically changes the regulation mode to maintain stability across all operating conditions, preventing oscillations during no-load while ensuring reliability during loaded operation.
Solution Approach 2:
The invention changes the regulation parameter from DC voltage to AC voltage based on load conditions. By monitoring the load state and switching the regulation target between DC and AC voltage, the system adapts to different operating conditions and maintains optimal performance across the full range of loads.
2Reliability
If DC voltage regulation is used during load transients, then voltage overshoot occurs leading to overvoltage faults, but using AC voltage regulation prevents this
Solution Approach 1:
The system dynamically selects the regulation mode based on real-time load conditions. During load transients, the regulator selector detects the changing load state and switches to AC voltage regulation, which prevents voltage overshoot and overvoltage faults. During steady loaded operation, it uses DC voltage regulation for reliable voltage control.
Solution Approach 2:
The system takes preliminary action by monitoring load conditions and switching to AC voltage regulation before voltage overshoot can occur during load transients. This preventive switching prevents the harmful effect of overvoltage faults before they happen, rather than correcting them after occurrence.
3Device complexity
If a single voltage regulation mode is used, then the system is simple, but it cannot adequately address instability during no-load conditions or voltage overshoot during load transients
Solution Approach 1:
The voltage regulator is designed with multi-functionality, incorporating both DC voltage regulation and AC voltage regulation capabilities within a single device. The regulator selector intelligently chooses the appropriate regulation mode based on load conditions, making the single regulator universal enough to handle all operating conditions reliably without requiring multiple separate regulators.
Data Source
AI summary
Systems and methods for voltage regulation of high voltage direct current systems are provided. In certain embodiments, a system includes a generator that generates alternating current (AC) voltage. The system further includes a power converter that converts the AC voltage into regulated direct current (DC) voltage. Also, the system includes a voltage regulator. In additional embodiments, the voltage regulator includes an AC voltage regulator that regulates the AC voltage generated by the generator. Also, the voltage regulator includes a DC voltage regulator that regulates the DC voltage produced by the power converter. Moreover, the voltage regulator includes a regulator selector that selectively activates one of the AC voltage regulator and the DC voltage regulator based on a current from the power converter and at least one of a voltage of the generator and a voltage of the power converter.