Power System Stabilizer Damping Electro-Mechanical Oscillations
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Solution Overview
Problem
Island and island-like power systems face challenges in controlling the balance between power generation and load, leading to frequent voltage and frequency fluctuations and instability, which conventional stabilizing measures struggle to address effectively, especially without high-voltage devices.
Innovation Solution
A power system stabilizer comprising sensors, controllers, and dampers with resistors and IGBT modules that modulate current based on electro-mechanical oscillations to provide both transient and dynamic stability, using low-voltage components and distributed modules for scalability and redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stabilizing measures (transient stabilizers, dynamic stabilizers) are used in island power systems, then voltage and frequency stability is improved, but device complexity and requirement for high-voltage components increases
Solution Approach 1:
The patent replaces mechanical high-voltage stabilizing devices with a power electronic system using IGBT modules and a coupling transformer. The stabilizer uses controlled switching of power electronic components to generate damping currents, substituting complex mechanical high-voltage equipment with controllable electronic switches and a single coupling transformer, thereby reducing device complexity while maintaining stability enhancement.
2Reliability
If high-voltage devices are used for dynamic stability improvement, then transient stability performance is enhanced, but ease of operation and safety increases
Solution Approach 1:
The patent introduces a coupling transformer as an intermediary device that connects the low-voltage stabilizer circuit to the high-voltage power system. The transformer enables the stabilizer to inject damping currents into the high-voltage system while maintaining electrical isolation, allowing safe operation at low voltage and simplifying control without direct exposure to high-voltage risks.
3Ease of operation
If generator excitation control is used for dynamic stability improvement, then control simplicity is maintained, but transient stability performance is not noticeably enhanced
Solution Approach 1:
The patent segments the stability control function into two independent parts: the existing excitation control system and the new power system stabilizer. The stabilizer operates as a separate control loop that injects damping currents through the coupling transformer, independent of the excitation system. This segmentation allows the stabilizer to enhance transient stability performance without complicating the overall control structure, as it adds a dedicated damping function rather than modifying the existing excitation control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively stabilizes island and island-like power systems by damping electro-mechanical oscillations, enhancing both transient and dynamic stability without requiring high-voltage devices, and providing robustness against faults and fluctuations.
Implementation Method 1
a coupling transformer configured for coupling the at least two IGBT modules to the power system through a power bus
Implementation Method 2
a resistor configured for being coupled to the at least one IGBT module and dissipating energy
Data Source
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AI summary
A power system (10) stabilizer (12) includes: a sensor (14) configured for sensing a signal representative of electro-mechanical oscillations of the power system; a controller (16) configured for using the sensed signal for generating control signals for damping the electro-mechanical oscillations; and a damper (18) including a damping converter (20) and a resistor (22) coupled to the damping converter, the damping converter being coupled to the power system through a power bus (24), the damping converter configured for using the control signals for damping the electro-mechanical oscillations.