Smart Meter Non-Technical Loss Detection via Area-Based Current Measurement
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Solution Overview
Problem
Non-technical losses (NTL) in power grids occur due to unidentified, misallocated, or inaccurate energy flows, often caused by cyber attacks, tampering, or time skew in smart meter readings, which existing systems struggle to accurately detect and correct.
Innovation Solution
A method and system that measure the area under a squared root mean squared (RMS) current curve, active energy, and reactive energy to characterize cable reactance and resistance, allowing for the detection of active and reactive energy losses, and subsequently identifying non-technical losses by using these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If smart meters use instantaneous power measurements for NTL detection, then the detection can be performed with simple measurements, but time skew in smart meter clocks causes inaccurate measurements and false NTL detection
Solution Approach 1:
The patent changes the measurement parameter from instantaneous power to area under the squared RMS current curve. This parameter transformation eliminates the sensitivity to time skew while maintaining the ability to detect NTL, as the area under the curve integrates the squared current over time, making it invariant to temporal misalignment between smart meters.
2Measurement precision
If the system measures area under squared RMS current curve and calculates cable impedance, then NTL detection accuracy improves, but the measurement and calculation complexity increases
Solution Approach 1:
The smart meters perform self-diagnosis by measuring their own squared RMS current and calculating their own cable impedance characteristics. The system uses the smart meters' built-in measurement capabilities to detect NTL without requiring external complex measurement equipment, thereby reducing overall system complexity despite the more sophisticated calculation method.
3Measurement precision
If smart meters are synchronized to a common time reference, then accurate energy measurement is possible, but the system becomes vulnerable to cyber attacks that can manipulate time synchronization
Solution Approach 1:
The patent converts the harmful effect of time skew (which can be manipulated by cyber attacks) into a beneficial feature by using area under the squared RMS current curve measurements. This measurement approach is inherently robust to time synchronization issues, turning the vulnerability into a strength that makes the system more secure against cyber attacks targeting time synchronization.
Data Source
AI summary
A method for detecting non-technical losses in an electrical power system includes measuring an area under a squared RMS current curve for a power cable in the electrical power system over at least one time interval, measuring an active and a reactive energy for the power cable over the at least one time interval, and characterizing a cable reactance and a cable resistance using the active energy, the reactive energy, and the area under the squared RMS current curve. The method further includes determining an active energy loss and a reactive energy loss over the at least one time interval using the area under the squared RMS current curve and the reactance and the resistance of the cable, and detecting a non-technical loss in the electrical power system based on the active energy loss and the reactive energy loss over the at least one time interval.