Virtual Voltage RMS Detection for Fast Multi-Phase AC Faults
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Solution Overview
Problem
Conventional RMS value measurements in multi-phase AC power systems require large sample windows, leading to delayed fault detection and adversely affecting system transient performance and reliability.
Innovation Solution
Constructing a virtual voltage signal from voltage samples captured in a shortened sample window of T/2/N to emulate RMS voltage, reducing measurement and fault detection delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large sample window (T/2) is used for RMS value measurements, then measurement accuracy is improved, but fault detection time is delayed
Solution Approach 1:
The patent divides the traditional T/2 sample window into N smaller segments, each of duration T/2/N. By processing multiple phases (N phases) with these segmented windows, the system achieves accurate RMS calculation while reducing the effective measurement delay. The segmentation allows parallel processing of different phase signals to compensate for the reduced window size.
Solution Approach 2:
The patent performs preliminary processing of voltage samples from N phases within the shortened T/2/N window by combining them to reconstruct a virtual single-phase signal. This preliminary combination of multi-phase data compensates for the reduced sample window duration, enabling accurate RMS calculation to be achieved earlier than conventional methods.
2Loss of time
If a shortened sample window (T/2/N) is used for RMS value measurements, then fault detection time is reduced, but measurement accuracy deteriorates
Solution Approach 1:
The patent merges voltage samples from N different phases, each captured in a shortened T/2/N window, to reconstruct a virtual single-phase voltage signal. By combining these N segments, the system effectively synthesizes a complete half-cycle waveform, thereby achieving accurate RMS measurement despite using a shortened individual sample window for each phase.
Solution Approach 2:
The patent introduces a virtual reconstructed voltage signal as an intermediary between the shortened multi-phase samples and the final RMS calculation. This virtual signal serves as a mediator that preserves the accuracy requirements for RMS measurement while enabling the use of shortened sample windows, thus resolving the contradiction between speed and precision.
3Reliability
If conventional RMS measurement methods are used, then system reliability is maintained, but transient performance deteriorates due to detection delay
Solution Approach 1:
The patent implements a dynamic fault detection approach by using a shortened adaptive sample window of T/2/N that is optimized for transient conditions. This dynamic window size allows the system to respond more quickly to transient faults while maintaining measurement accuracy through the multi-phase combination technique, thereby improving transient performance without sacrificing reliability.
Data Source
AI summary
In an embodiment, voltage fault detection is performed for alternating current (AC) multi-phase power systems based on a reconstructed or virtual voltage signal derived from voltage samples captured in a shortened sample window to reduce fault detection time. The embodiment of the present disclosure constructs the virtual voltage signal (emulating the root mean square (RMS) voltage of any of the phases) from the voltage samples captured from signals of the multi-phase power system. The embodiment of the present disclosure employs a shortened sample window of T/2/N (N is the number of phases ≥3) to capture the voltage samples, thereby reducing measurement and fault detection delay. The virtual voltage signal is used determine root mean square (RMS) voltage for voltage fault detection.