PRP Network Error Detection Using IED Duplicate-Frame Counters

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Solution Overview

Problem

Existing PRP networks do not adequately detect protocol-specific and node-level failures, leading to unnoticed system vulnerabilities and increased risk of failure, especially in critical infrastructure systems using GOOSE and Sampled Value protocols.

Innovation Solution

Implement an IED with a link redundancy entity and node-level redundancy error detection subsystem that maintains records of missing duplicate frames across LANs, detecting discrepancies and self-announcing errors based on specific protocols, thereby ensuring reliable communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional PRP network monitoring is used, then network-level failures can be detected, but node-level and protocol-specific failures remain undetected

Engineering Contradiction:

Improvefailure detection capabilityVSAvoiddetection granularity

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the monitoring function into multiple levels: network-level monitoring (detecting complete LAN failures) and node-level monitoring (detecting individual device failures). It further segments protocol monitoring by tracking specific protocols (GOOSE, Sampled Value) separately. This segmentation enables detailed detection of node-level and protocol-specific failures that were previously invisible in traditional PRP monitoring.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism - the discrepancy counter - that mediates between received frames and expected duplicate frames. By maintaining records of expected frames and comparing them with actual receptions, the intermediary detects missing frames indicating node-level failures. This intermediary layer enables indirect detection of failures without requiring direct observation of all network traffic.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If redundancy is implemented without error detection, then system simplicity is maintained, but unnoticed system vulnerabilities increase

Engineering Contradiction:

Improvesystem structureVSAvoidsystem vulnerability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements self-service by having each IED autonomously monitor its own frame reception and generate discrepancy counters locally. Each device independently tracks expected versus received frames and self-announces errors without requiring external monitoring systems. This distributed self-monitoring approach adds reliability while maintaining relative system simplicity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent establishes feedback mechanisms where IEDs continuously monitor their frame reception, compare received frames against expected duplicates, and generate feedback signals (discrepancy counters) that trigger error announcements. This closed-loop feedback system enables automatic detection and reporting of node-level failures, transforming passive redundancy into active self-diagnosis.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12445236B2Parallel redundancy protocol error detection

Publication Date: 2025.10.14 SCHWEITZER ENGINEERING LABORATORIES INC

AI summary

This disclosure pertains to systems and methods to detect network errors in a parallel redundant protocol (PRP) network. A node-level redundancy error subsystem of an intelligent electronic device (IED) maintains records (e.g., counts) of information associated with missing duplicate frames expected from node devices on the PRP network via redundant first and second local area networks (LANs). Non-zero counts of missing duplicate frames may be identified as network errors.