Substation Lockout Function Block Simplifies Engineering

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Solution Overview

Problem

The existing methods for implementing protection lockout functionality in substation automation systems are complex and inefficient, requiring manual reset of bi-stable relays and complex logical wiring for multiple protection zones, especially in dynamic configurations, which complicates engineering and supervision.

Innovation Solution

A method that simplifies engineering and supervision by incorporating protection zone intelligence into lockout function blocks at breaker IEDs, using virtual lockout relays and zone IDs to manage trip and reset messages, allowing automatic configuration and reduced complexity in system modifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bi-stable relays are used for lockout function in each protection zone, then the lockout function can be implemented reliably, but the device complexity and wiring complexity increase significantly

Engineering Contradiction:
Improvelockout function reliabilityVSAvoidwiring complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple separate bi-stable relays (one for each protection zone) into a single shared bi-stable relay. The relay is controlled through different zone identifiers and trip messages, allowing one relay to serve multiple protection zones. This consolidation reduces wiring complexity while maintaining the reliability of lockout functionality across all zones.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single bi-stable relay is designed to perform multiple functions by responding to different zone identifiers and trip messages. The relay can be set by trip messages from any protection zone and reset by a single reset message, making it a universal lockout mechanism that replaces multiple zone-specific relays. This multi-functionality reduces the overall number of devices needed in the system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If separate bi-stable relays are provided for each protection zone, then the lockout state can be independently managed per zone, but the ease of operation and manual reset process become more complex

Engineering Contradiction:
Improveindependent zone lockout managementVSAvoidmanual reset operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent introduces a centralized reset mechanism that acts as an intermediary between operators and the lockout system. Instead of requiring operators to manually reset individual relays for each zone, a single reset message is broadcast through the communication network to the shared bi-stable relay. This intermediary mechanism simplifies operator interaction while maintaining independent zone management through zone identifiers in the trip messages.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If IEC 61850 communication protocol is used to replace wiring, then the ease of manufacture and installation improve, but the device complexity increases due to complex logical wiring requirements

Engineering Contradiction:
Improveinstallation easeVSAvoidlogical wiring complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent uses digital copies of zone identifiers and trip messages instead of physical wiring connections. Each protection zone is represented by a unique identifier that is copied and transmitted through the IEC 61850 communication network to the shared bi-stable relay. This digital copying approach replaces complex physical and logical wiring with simplified communication protocols, reducing engineering effort while maintaining system functionality.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2441146B1Protection lockout in substation automation
Publication Date: 2020.04.01 ABB POWER GRIDS SWITZERLAND AG
  • EP2441146B1 patent drawingFigure 1~2

AI summary

The present invention is concerned with simplified engineering of protection lockout functionality in a Substation Automation (SA) system. Wiring complexity as well as supervision related engineering is replaced by including some protection-zone related intelligence into a lockout function block at a breaker IED. The main configuration effort then consists in assigning lockout function instances to respective protection zones, and in specifying for each protection function which protection-zone(s) it shall trip and reset after lockout. Hence for switch yard configurations and power networks where a protection function trips multiple breakers by using several bay control or protection devices a more efficient implementation of lockout functionality is possible.