Electric Meter Outage Detection Using Frequency and Zero Crossings
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Solution Overview
Problem
Existing electrical systems struggle to accurately monitor and measure short-duration power interruptions in power grids, particularly at smaller scales, which affects the accuracy of indices like SAIDI.
Innovation Solution
An electric meter equipped with a metrology circuit that includes current and voltage sensors, an analog-to-digital converter, and a digital control device to measure frequency and zero crossing events, allowing precise identification and recording of power interruptions, even during battery operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If centralized monitoring systems are used to monitor power interruptions, then large-scale power outages can be identified effectively, but smaller-scale power outages with shorter durations cannot be identified accurately
Solution Approach 1:
The patent divides the monitoring function into two levels: centralized monitoring for large-scale outages and distributed smart meter monitoring for smaller-scale interruptions. Each smart meter independently monitors local power quality and detects interruptions, then reports data to the centralized system. This segmentation allows accurate detection of both large and small interruptions without requiring the centralized system to handle all detection tasks directly.
Solution Approach 2:
Smart meters act as intermediary devices between the power distribution network and the centralized monitoring system. They perform local measurement and preliminary analysis of power interruptions, filtering and processing data before transmitting to the centralized system. This intermediary layer enables accurate detection of small-scale interruptions while reducing the processing burden on the centralized system.
2Reliability
If existing monitoring systems are used, then power interruption monitoring can be performed, but the measurement of short-duration interruptions is inaccurate
Solution Approach 1:
The smart meters continuously monitor voltage and current parameters before interruptions occur, establishing baseline data. When an interruption happens, the meters immediately detect the change from the pre-established baseline, enabling accurate measurement of even very short-duration interruptions. This preliminary monitoring action ensures no interruption goes undetected regardless of duration.
Solution Approach 2:
The system performs periodic sampling of power parameters at high frequency intervals during potential interruption events. By taking multiple rapid measurements during the interruption period, the system can accurately determine the exact start and end times of interruptions, even those lasting only fractions of a second, thereby improving duration measurement precision.
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
Enables accurate and fine-grained tracking of power interruption durations, improving the calculation of indices like SAIDI by capturing even short interruptions, enhancing the reliability assessment of power grids.
Implementation Method 1
the control device measures an accumulated value of zero crossing events in the AC power signal
Implementation Method 2
the control device measures frequency of the AC power signal
Data Source
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AI summary
A method identifies a duration of power interruptions in an electrical monitoring system. The method includes receiving, with an external monitoring system, a load profile from an electric meter that includes at least one of an accumulated frequency measurement and an accumulated number of zero crossing events that the electric meter records in an AC power signal during a predetermined monitoring period, and identifying a total duration of at least one power interruption during the predetermined monitoring period based on at least one of a deviation of the accumulated frequency measurement in the load profile from a predetermined accumulated frequency value or a deviation of the accumulated number of zero crossing events in the load profile from a predetermined number of zero crossing events during the predetermined monitoring period.