Dynamic Tracking Filter Bandwidth for Voltage Sag Detection
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Solution Overview
Problem
Industrial control systems face reliability issues and productivity losses due to abnormal grid conditions like voltage sags, which can cause over current faults and undesirable current harmonics, leading to excessive stress on power components and requiring manual resetting.
Innovation Solution
A method and apparatus for detecting and tracking signal sags in power systems, involving a sag detection module that monitors transitions using a tracking filter, adjusts bandwidth to maintain signal tracking during sag conditions, and recovers when the signal returns to normal, ensuring timely detection and response to voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed bandwidth tracking filter is used to monitor voltage sags, then the system maintains stable operation during normal conditions, but the detection speed and responsiveness deteriorate when voltage sags occur
Solution Approach 1:
The tracking filter bandwidth is made dynamic rather than fixed. The system automatically adjusts the bandwidth based on operating conditions: using a first bandwidth value during normal operation for stability, and switching to a second bandwidth value when voltage sags are detected to improve detection speed and responsiveness. This dynamic adaptation resolves the contradiction between maintaining stability and achieving fast detection.
2Reliability
If manual resetting is required for over current faults, then system reliability is maintained by preventing automatic operation during faults, but productivity deteriorates due to time and resource losses
Solution Approach 1:
The system performs preliminary detection of voltage sags before they cause over current faults and converter malfunctions. By detecting sags early using the tracking filter and providing advance warning, the system allows for preventive actions to be taken before the fault occurs, thereby maintaining reliability while avoiding the productivity loss associated with manual resetting after faults.
Solution Approach 2:
The system implements continuous feedback monitoring of voltage conditions through the tracking filter. This feedback mechanism provides real-time information about voltage sags, enabling the control system to respond appropriately and prevent fault conditions that would require manual intervention, thus maintaining both reliability and productivity.
3Device complexity
If voltage sags are not monitored, then system complexity is reduced, but manufacturing precision deteriorates due to inefficient operation of expensive devices
Solution Approach 1:
The tracking filter serves as an intermediary component that monitors voltage conditions without adding significant system complexity. It processes voltage signals to detect sags while maintaining a simple structure, thereby enabling precise operational monitoring and preventing inefficient operation of expensive industrial devices without substantially increasing device complexity.
Data Source
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AI summary
Described herein are methods, systems, and apparatuses for determining sag in a signal. In one example, a method of tracking sag in a signal includes, when in an initial state, monitoring for when the signal transitions to a sag state based at least on an output of a tracking filter. In response to the signal transitioning to the sag state, increasing a bandwidth of the tracking filter and, when in the sag state, monitoring for when the signal transitions to a recovering state. The method further includes, in response to the signal transitioning to the recovering state, decreasing the bandwidth of the tracking filter.