Power Consumption Estimation in Ungrounded Feeder Sections
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Solution Overview
Problem
Existing methods for determining power consumption in ungrounded power distribution systems face limitations in processing time and estimation accuracy, especially during real-time applications and single-phase-to-ground fault conditions, due to similar fault currents and load currents.
Innovation Solution
A method and system that represent power consumption as a product of a scaling factor and base power based on load profiles, adjusting these values iteratively using measurements from importing and exporting measuring devices, and accounting for shunt currents and phase-to-phase power differences through transformations and incremental calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If load profiles are used for power consumption estimation, then processing time is reduced, but estimation accuracy deteriorates due to inability to capture real-time variations
Solution Approach 1:
The system pre-calculates and stores load profiles during normal operating conditions. These pre-computed profiles serve as a foundation for rapid estimation during fault conditions, eliminating the need for real-time complex calculations while maintaining reasonable accuracy through subsequent iterative refinement.
Solution Approach 2:
The system implements an iterative refinement process where initial power consumption estimates based on load profiles are continuously adjusted using feedback from power flow solutions and measurements. The estimates are updated until the difference between calculated and measured values falls within a threshold, ensuring accuracy while maintaining computational efficiency.
2Difficulty of detecting and measuring
If fault current measurement is used for fault location, then detection simplicity is improved, but measurement precision deteriorates because fault currents are similar in magnitude to load currents in ungrounded systems
Solution Approach 1:
The system segments the feeder into multiple sections and calculates equivalent loads for each section. By dividing the problem into manageable segments and computing power flow for each, the system can accurately determine which specific section contains the fault, transforming a difficult single-measurement problem into a series of simpler segmented calculations.
Solution Approach 2:
The system introduces power flow calculation and equivalent load computation as intermediary steps between raw current measurement and fault location determination. These intermediaries transform the ambiguous current measurements into meaningful power consumption estimates that clearly indicate fault locations, bridging the gap between simple measurement and precise determination.
3Measurement precision
If iterative power flow solution is implemented, then power consumption estimation accuracy is improved, but processing time increases
Solution Approach 1:
The system performs preliminary power flow calculations during normal operating conditions to establish baseline load profiles. These pre-computed profiles are stored and reused during fault conditions, eliminating the need for iterative calculations in real-time while maintaining accuracy through the use of pre-analyzed system characteristics.
Solution Approach 2:
The system applies iterative refinement only when necessary - specifically during fault conditions where accurate real-time estimation is critical. During normal operation, the system relies on pre-computed profiles without iteration, thus applying the computationally intensive iterative process partially rather than continuously, balancing accuracy with processing efficiency.
Data Source
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AI summary
A method determines power consumption of a load in a feeder section of an ungrounded power distribution system. Borders of the feeder section are defined by an importing device connecting the feeder section to an upstream feeder section, and by at least one exporting device connecting the feeder section with a downstream feeder section. A power consumption of each load is represented as a product of a scaling factor and a base power defined by a load profile of the load. A power flow of the feeder section is solved using the power consumptions of the loads to produce an active power for each phase of the importing device. A target active power for each phase of the importing device is determined using measurements at the importing device, and the scaling factors are updated based on a difference between the active power and the target active power.