Substation Protection Blocking for Lost Time Synchronization

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Solution Overview

Problem

Substation networks face issues with false trips due to transient time differences between data sources caused by lost time synchronization, leading to inefficient protection function operations.

Innovation Solution

An intelligent electronic device (IED) method and system that blocks the protection function upon detecting a time shift between data streams until a configured time amount has expired, ensuring synchronized data sources prevent false trips and optimize protection function utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the protection function is blocked to avoid false trips during time synchronization loss, then reliability is improved, but productivity deteriorates due to unnecessary blocking

Engineering Contradiction:

Improveprotection function reliabilityVSAvoidprotection function utilization

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary detection of time shifts in data streams before blocking the protection function. By monitoring time synchronization status and detecting time shifts in advance, the system blocks the protection function only when actually needed, avoiding unnecessary blocking and maintaining high utilization while preventing false trips.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If time synchronization is propagated hierarchically throughout the substation network, then measurement precision is improved, but loss of time increases due to substantial propagation delay

Engineering Contradiction:

Improvetime synchronization precisionVSAvoidtime shift propagation delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The IED acts as an intermediary that detects time shifts in data streams from multiple data sources and coordinates the blocking of the protection function. This intermediary approach allows the system to maintain hierarchical time synchronization for precision while minimizing the impact of propagation delays by reacting locally to detected time shifts rather than waiting for system-wide propagation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If the protection function operates with time shifted data streams, then productivity is improved, but reliability deteriorates due to false trips

Engineering Contradiction:

Improveprotection function availabilityVSAvoidtrip decision accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system implements feedback by continuously monitoring data streams for time shifts and using this information to control the protection function operation. When time shifts are detected, the protection function is blocked; when time synchronization is restored, operation resumes. This feedback mechanism ensures the protection function operates only with properly synchronized data, maintaining both reliability and productivity.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12166350B2Handling of lost time synchronization in a substation network

Publication Date: 2024.12.10 HITACHI ENERGY LTD

AI summary

There is provided mechanisms for handling time shifted data streams in a substation network. A method is performed by an IED. The method comprises receiving a respective data stream from at least two time synchronized data sources in the substation network. The method comprises blocking, upon detecting a time shift between the data streams resulting from one of the data sources losing its time synchronization and until a configured time amount has expired, a protection function in the substation network from acting based on the data streams.