Manifold Regularization for Time Domain Fault Location

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Solution Overview

Problem

Current methods for estimating fault location in time domain protection of power systems are inefficient due to their reliance on solving differential equations for instantaneous impedance, which are computationally intensive and lack precision and speed, especially when dealing with high-dimensional heterogeneous data.

Innovation Solution

A machine-learning model is trained using manifold regularization techniques, incorporating a non-smoothness penalization function and phasor-deviation penalization to minimize error and improve smoothness, with adaptive weight learning and clustering to enhance robustness and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If differential equations are solved for instantaneous impedance estimation, then fault location precision is improved, but computational time increases

Engineering Contradiction:
Improvefault location precisionVSAvoidcomputational time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical/computational process of solving differential equations with a machine learning model that has been trained offline. The trained model directly estimates fault location from impedance measurements without requiring real-time differential equation solving, thus substituting a complex computational mechanism with a simpler, faster inference process while maintaining estimation accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs the complex differential equation solving and model training in advance (offline phase) to create a pre-trained machine learning model. During actual fault detection (online phase), the pre-trained model is used for rapid estimation without requiring real-time differential equation solving, thus preparing the solution beforehand to eliminate computational delays during critical fault events.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If machine-learning model complexity is increased to handle high-dimensional heterogeneous data, then estimation accuracy is improved, but training time and computational resources increase

Engineering Contradiction:
Improvefault location estimation accuracyVSAvoidtraining efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the training process into distinct phases: data preprocessing, feature extraction, model training, and validation. The heterogeneous high-dimensional data is processed through multiple stages including clustering, dimensionality reduction, and feature selection before being fed to the machine learning model. This segmentation allows complex tasks to be broken down into manageable steps, improving both accuracy and training efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies manifold regularization with adaptive weighting that dynamically adjusts parameters during training based on data characteristics. The regularization parameter and weight coefficients are optimized to balance model complexity and generalization performance, allowing the model to effectively handle high-dimensional heterogeneous data without requiring excessive computational resources or training time.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20240112073A1Regularization techniques to improve efficiency of time domain protection
Publication Date: 2024.04.04 HITACHI ENERGY LTD
  • US20240112073A1 patent drawing
  • US20240112073A1 patent drawing
  • US20240112073A1 patent drawing

AI summary

One component of time domain protection in a power system is estimating the location of a fault. In an embodiment, a multi-objective problem is formulated that comprises a non-smoothness penalization function that drives the primary objective function for fault location estimation towards a solution that respects smoothness between the inputs and outputs of a machine-learning model. This technique improves the accuracy, blind zone, and speed of state-of-the-art techniques, in the context of time domain protection, as well as for other regression tasks. In an additional or alternative embodiment that is specific to time domain protection, the multi-objective problem may comprise a phasor-deviation penalization function that drives the primary objective function towards a solution that minimizes deviations in phasor values. The trained machine-learning model may be executed in a line protection system to determine whether or not to trip a circuit breaker of a power line.