Reactive Power Converter Control Using Grid Frequency Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power system stabilization devices require multiple detectors to measure system voltage and active power, and their control parameters need to be adjusted based on the specific characteristics of each power system, making them complex and less effective in suppressing generator rotational speed variations.
Innovation Solution
A power conversion device connected to a power transmission line, equipped with a frequency detector to measure system frequency, a controller to generate reactive power command values, and a power converter to output reactive power, allowing for direct control of generator rotational speed variations without the need for multiple detectors or system-specific parameter adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple detectors (current detector and voltage detector) are installed on the power transmission line to measure system voltage and active power, then the power system stabilization device can implement system voltage control and power swing suppression control, but the device complexity increases due to the need for many detectors
Solution Approach 1:
The patent extracts and utilizes the frequency detection function from the complex detector system. Instead of using multiple detectors (current and voltage detectors) to measure system voltage and active power, the invention uses a frequency detector to detect system frequency, which indirectly provides information about power system swings. This extraction of the essential frequency parameter simplifies the detector configuration while maintaining stabilization capability.
Solution Approach 2:
The frequency detector serves multiple functions: it detects system frequency variations that indicate generator rotational speed changes, provides information about power system swings, and enables reactive power control. This single frequency detector replaces what would traditionally require multiple detectors, demonstrating multi-functionality that reduces device complexity while maintaining reliability.
2Adaptability or versatility
If control parameters are adjusted depending on the specific characteristics of each power system, then the power system stabilization device can adapt to different systems, but the ease of operation decreases due to the need for parameter adjustments
Solution Approach 1:
The patent changes the control parameter from active power (which requires system-specific calibration) to system frequency. Frequency is a universal parameter that directly reflects generator rotational speed and power system swing conditions regardless of the specific power system configuration. This parameter change eliminates the need for system-specific parameter adjustments while maintaining adaptability to different power systems.
Solution Approach 2:
The frequency detector provides continuous feedback about system frequency variations, which the controller uses to automatically adjust reactive power output. This feedback mechanism eliminates the need for manual parameter adjustments by automatically adapting to different power system conditions through real-time frequency monitoring and reactive power control.
3Reliability
If a frequency detector is used to detect system frequency and a controller generates reactive power command values to compensate for frequency variations, then the generator rotational speed variation is suppressed, but the power conversion device complexity increases
Solution Approach 1:
The patent introduces frequency as an intermediary parameter that mediates between generator rotational speed and reactive power control. Instead of directly controlling generator speed or using complex multi-detector systems, the frequency detector measures system frequency (which reflects rotational speed), and the controller uses this frequency information to generate reactive power commands. This intermediary approach simplifies the overall device configuration while achieving rotational speed stabilization.
Data Source
AI summary
A power conversion device is connected to a power transmission line which is connected to a generator. The power conversion device includes a frequency detector that detects a system frequency, the system frequency being a frequency of an AC voltage on the power transmission line, a controller that generates a reactive power command value to compensate for a variation in the detected system frequency, and a power converter that outputs reactive power in accordance with the reactive power command value to the power transmission line.