Power Distribution Phase Identification for Mixed Wye-Delta Loads

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Solution Overview

Problem

Existing methods for phase identification in power distribution systems with mixed wye and delta connected loads, varied penetration rates of smart meters, and insufficient data labeling are inaccurate and costly, particularly in systems with high penetration of photovoltaic (PV) distributed power generation resources.

Innovation Solution

A data-driven event-triggered phase identification method using information theory to analyze smart meter measurements, examining cross entropy from mutual information between customer locations and feeder heads to identify phases in wye and delta connected loads, without requiring deep learning, training, or labeled data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If advanced sensors with phasor measuring capability are deployed at all customer sides, then phase identification accuracy is improved, but system cost increases significantly

Engineering Contradiction:
Improvephase identification accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent uses inexpensive smart meters that are already deployed at customer premises instead of expensive advanced sensors with phasor measuring capability. The smart meters provide sufficient measurement data (real power, reactive power, voltage magnitude) for phase identification through information theory-based analysis of event signatures, eliminating the need for costly specialized equipment at each customer location.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Ease of operation

If traditional correlation or regression methods are used for phase identification, then implementation simplicity is maintained, but identification accuracy deteriorates due to cross interference from mixed wye and delta load connections

Engineering Contradiction:
Improveimplementation simplicityVSAvoidphase identification accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transforms the approach by changing the analytical parameters from direct correlation/regression of event signatures to mutual information analysis of probability distributions. By computing marginal probability distributions of event signatures and applying information theory metrics, the method effectively handles mixed wye and delta load connections without the cross-interference problems that plague traditional correlation-based methods.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If high sampling rates are used in smart meter measurements, then measurement precision is improved, but data processing complexity and computational burden increase

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential features needed for phase identification from the measurement data - specifically, event signatures defined by current exceeding fluctuations above a threshold. By focusing on these extracted event features rather than processing complete high-rate measurement data, the method achieves accurate phase identification while significantly reducing computational burden and data processing complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If more measurement locations are deployed, then phase identification accuracy is improved, but system complexity and deployment cost increase

Engineering Contradiction:
Improvephase identification accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables phase identification using only the measurement data already collected by smart meters at customer premises for billing purposes. The method extracts event signatures from existing smart meter measurements (real power, reactive power, voltage) and uses information theory analysis to identify phases, eliminating the need for additional measurement devices or infrastructure at both customer and utility sides.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS12607662B2Phase identification of power distribution systems
Publication Date: 2026.04.21 MITSUBISHI ELECTRIC RESEARCH LABORATORIES INC
  • US12607662B2 patent drawing
  • US12607662B2 patent drawing
  • US12607662B2 patent drawing

AI summary

Method and system for phase detecting of hybrid wye-connected and delta-connected loads in an unbalanced power distribution system. A data-driven event-triggered phase identification algorithm is presented in which the exceeding current fluctuation events are used to build the relationship between the feeder head and the undetermined phase load and mutual information index is used to assess the dependence level of the feeder head on the undetermined phase load. The connected and non-connected phase of wye-connected and delta-connected single-phase load are determined as the phase having highest and lowest dependences of the phases of feeder head on the load, respectively.