Low-impact Power Grid Probing via Frequency Offset Filtering
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Solution Overview
Problem
Existing methods for determining power grid characteristics using broadband probe signals introduce significant disturbances and interference, making it difficult to collect accurate data, especially when there are constraints on permitted disturbance levels in power grid systems.
Innovation Solution
A method employing a signal filter to extract a sample signal from the power grid signal, allowing for the injection of low-amplitude probe signals at a frequency different from the frequency of interest, enabling the determination of grid characteristics with minimal disturbance by isolating the probe signal response using a digital filter or FFT, and adjusting the filter bandwidth and probe signal amplitude to optimize resolution and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a broadband probe signal with high amplitude is injected into the power grid, then the response signal becomes identifiable and grid characteristics can be determined, but significant disturbance and interference are introduced into the grid
Solution Approach 1:
The patent segments the frequency spectrum by using a narrowband probe signal at a specific frequency rather than a broadband signal. The probe signal is injected at a frequency different from the frequency of interest, allowing the response to be extracted through filtering. This segmentation approach concentrates the probe energy at a single frequency, reducing overall grid disturbance while maintaining measurable response through selective frequency analysis.
Solution Approach 2:
The patent introduces a signal filter as an intermediary component that separates the probe signal response from the power grid signal. The filter extracts the sample signal at the probe frequency from the composite signal containing both grid operations and probe response. This intermediary filtering mechanism enables detection of low-amplitude probe responses without requiring high injection levels that would cause grid disturbance.
2Object-affected harmful factors
If the probe signal amplitude is reduced to minimize grid disturbance, then customer constraints on permitted disturbance are met, but the response signal becomes difficult to distinguish from background noise
Solution Approach 1:
The patent applies preliminary filtering action by determining the signal filter configuration before injecting the probe signal. The filter bandwidth and characteristics are pre-determined based on the probe signal frequency and expected response characteristics. This preliminary setup ensures that when the low-amplitude probe signal is injected, the filter is already optimized to extract the response signal from background noise, enabling detection despite reduced probe amplitude.
Solution Approach 2:
The patent changes the frequency parameter of the probe signal to be different from the frequency of interest. By operating at an offset frequency, the probe response can be extracted through frequency-selective filtering without interfering with the primary grid operations at the frequency of interest. This parameter change allows low-amplitude probing while maintaining signal detectability through frequency domain separation.
3Object-affected harmful factors
If a narrowband probe signal at a frequency different from the frequency of interest is used, then grid disturbance is minimized and continuous monitoring is enabled, but the filter bandwidth must be precisely tuned to resolve the sample signal from the power grid signal
Solution Approach 1:
The patent implements feedback by determining the signal filter characteristics based on the probe signal frequency and the frequency of interest. The filter bandwidth and center frequency are configured according to the offset frequency relationship. This feedback-based configuration ensures that the filter is optimally tuned to extract the probe response while rejecting the power grid signal at the frequency of interest, reducing the complexity of manual filter design.
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
This approach allows for continuous, accurate monitoring of power grid characteristics with minimal disturbance, ensuring that the probe signals are below detectable thresholds, thereby maintaining grid stability and compliance with customer constraints.
Implementation Method 1
determining a signal filter for extracting a sample signal from a power grid signal, the signal filter being configured to filter frequencies outside of a filter bandwidth from the power grid signal
Implementation Method 2
The probe signal will induce a response in the grid according to the characteristics thereof. Thus, the response can be measured as a means for determining characteristics of the power grid.
Data Source
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AI summary
There is disclosed herein a computer-implemented method for determining characteristics of a power grid. The method comprises determining a signal filter for extracting a sample signal (102S) from a power grid signal (102G), the signal filter being configured to filter frequencies outside of a filter bandwidth (FB) from the power grid signal. The method further comprises generating a probe signal for injecting into the power grid to investigate a component (102C) of the power grid signal at a frequency of interest (f0), the probe signal having an injection frequency (fS) different to the frequency of interest. The injection frequency is spaced from the frequency of interest such that the sample signal is resolvable, using the determined signal filter, from the component of the power grid signal, and the sample signal responds to the probe signal according to the one or more characteristics of the power grid at the frequency of interest. The method then further comprises injecting the probe signal into the power grid, extracting the sample signal from the power grid signal using the signal filter, and determining the one or more characteristics of the power grid at the frequency of interest based on the sample signal.