Dynamic Overcurrent Relay Coordination via Graph Traversal

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Solution Overview

Problem

Existing electric power distribution systems face challenges in scalable automatic coordination of overcurrent relays during network reconfigurations, which can lead to suboptimal protection settings and increased damage to utility equipment.

Innovation Solution

A method and system utilizing a network graph searching mechanism and heuristic protection setting module to automatically coordinate protection settings for geographically dispersed overcurrent relays, incorporating a graph traversal mechanism to determine optimal settings and apply directional protection, and rule-based modules for scalable and fast protection coordination across multiple network reconfigurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If primary and alternate protection setting groups are used for overcurrent relays during switching events, then coordination is provided for limited reconfigurations, but the system is not scalable to arbitrary numbers of network reconfigurations

Engineering Contradiction:
Improvecoordination capabilityVSAvoidsystem scalability
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The protection setting is changed from static pre-defined groups to dynamic calculation based on current network topology. The system continuously updates relay settings according to the present configuration of switches and sources, enabling adaptation to any number of reconfigurations without requiring additional pre-defined setting groups.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The relay protection parameters (time dial settings, pickup currents) are automatically recalculated and adjusted based on the current network topology. This parameter adaptation allows the system to handle arbitrary reconfigurations by changing settings in real-time rather than relying on fixed pre-defined groups.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If pre-defined setting groups are selected until no coordination issues occur, then coordination is achieved, but the protection speed is not optimized and damage to utility equipment increases

Engineering Contradiction:
Improvecoordination accuracyVSAvoidprotection response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system implements a feedback mechanism where the coordination result is evaluated and used to automatically adjust the protection settings. The coordinator calculates optimal settings based on the evaluated coordination status, ensuring both accuracy and speed by iteratively optimizing the time dial settings rather than relying on slow selection from pre-defined groups.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The optimal protection settings are calculated in advance based on the network topology before a fault occurs. This preliminary calculation of time dial settings ensures that when a fault happens, the coordination is already optimized for fastest protection, eliminating the need for slow post-fault adjustment or selection from pre-defined groups.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If manual coordination of overcurrent relays is performed, then protection settings can be adjusted, but the process is time-consuming and cannot keep pace with automatic network reconfiguration

Engineering Contradiction:
Improvecoordination flexibilityVSAvoidcoordination speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The protection coordination system performs self-service by automatically calculating and adjusting its own settings without manual intervention. The coordinator module autonomously evaluates the network topology and computes optimal time dial settings for all relays, enabling the system to keep pace with automatic network reconfiguration while maintaining coordination flexibility.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical adjustment of relay settings is replaced by an automated computational system. The coordinator uses algorithms to calculate optimal time dial settings and automatically configures the relays, substituting the slow manual process with fast electronic computation and adjustment that can keep pace with automatic network reconfiguration.

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

Data Source

PatentEP3756252B1Method for automatically coordinating protection settings in an electric power distribution network
Publication Date: 2022.10.26 S&C ELECTRIC CO
  • EP3756252B1 patent drawingFigure 1
  • EP3756252B1 patent drawingFigure 2
  • EP3756252B1 patent drawingFigure 3

AI summary

Methods and systems are provided for automatically coordinating protection settings for relays within an electrical power distribution network. A method includes using a graph traversal mechanism to analyze geographical-based equipment data that contains information about overcurrent relays within the electrical power distribution network. A customizable rule base is applied to protection guidelines. Protection settings are determined based upon the applied customizable rule base and the direction of fault current flow from each source. The determined protection settings are used for the overcurrent relays to control switches in the electrical power distribution network in response to a detected fault.