Power System Frequency Detection Under Disturbance and Phase Jumps
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Solution Overview
Problem
Existing frequency detection methods in power systems struggle to quickly track changes in system frequency and suppress erroneous detections during system disturbances, particularly when phase jumps occur.
Innovation Solution
A system frequency detector using an orthogonal coordinate signal generator and a frequency calculator with a PLL-based angular frequency calculator, incorporating moving average filters, low-pass filters, and rate/saturation limiters to suppress high-frequency components and limit rapid frequency changes, ensuring accurate frequency tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microprocessor-based frequency detectors are used, then measurement precision is improved, but device complexity increases and response time deteriorates
Solution Approach 1:
The patent replaces microprocessor-based electronic frequency detection with a mechanical resonant system. The detector uses a piezoelectric element coupled to a mechanical resonator structure that naturally resonates at specific frequencies. When the input signal matches the resonant frequency, the mechanical system amplifies the response, providing precise frequency detection without requiring complex microprocessor circuits, ADCs, or software algorithms.
Solution Approach 2:
The patent changes the detection parameter from electronic signal processing to mechanical resonance frequency. By designing the mechanical resonator with specific physical dimensions and mass distribution, the system is tuned to resonate at the target frequency (e.g., 50Hz or 60Hz). This parameter-based approach enables precise frequency identification through the natural physical properties of the resonator rather than computational analysis.
2Measurement precision
If microprocessor-based frequency detectors are used, then measurement precision is improved, but response time worsens
Solution Approach 1:
The patent employs mechanical vibration and resonance to achieve rapid frequency detection. The piezoelectric element converts incoming acoustic or vibrational signals directly into mechanical resonance of the coupled resonator structure. When the input frequency matches the resonator's natural frequency, immediate resonant amplification occurs, providing instant frequency identification without the sampling, processing, and computational delays inherent in microprocessor-based systems.
3Device complexity
If conventional frequency detection methods are used, then device complexity is reduced, but adaptability to different frequency ranges worsens
Solution Approach 1:
The patent designs the mechanical resonator system with adjustable parameters that enable it to detect multiple frequency ranges. By changing the physical characteristics of the resonator (mass, stiffness, geometry) or adjusting the coupling mechanism, the same basic detector structure can be tuned to detect different frequencies. This universal design approach allows a single simple device to replace multiple frequency-specific detectors.
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 system frequency detector enables rapid tracking of frequency changes and reduces erroneous detections by suppressing high-frequency fluctuations and phase jumps, maintaining accuracy during system disturbances.
Implementation Method 1
a piezoelectric element, such as but not limited to, a piezoelectric disc, positioned to be in proximity to and vibrate with the tuning fork
Implementation Method 2
a piezoelectric element, such as but not limited to, a piezoelectric disc, positioned to be in proximity to and vibrate with the tuning fork
Implementation Method 3
The frequency detector may then be used to detect the presence of a particular frequency, such as but not limited to, the resonant frequency of the tuning fork
Data Source
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AI summary
According to an embodiment of the invention, a system frequency detector is provided and includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency, the frequency calculator further including a low-pass filter provided in series with the arithmetic unit, the low-pass filter suppressing a high frequency component of the system frequency. Thus, a system frequency detector is provided in which the change of the system frequency can be quickly tracked and an erroneous detection of the system frequency can be suppressed even when a system disturbance occurs.