Circuit Breaker Control Device Timing Compensation

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Solution Overview

Problem

Existing control devices for electrical power systems face challenges in accurately executing operational commands for circuit breakers due to internal processing delays and communication delays in the control device, leading to suboptimal point-on-wave switching and potential equipment damage.

Innovation Solution

A control device that calculates an absolute point in time for operational commands, independent of internal processing and message transfer times, using a central processing unit to synchronize with output modules and compensate for circuit breaker operating times, ensuring precise timing for switching operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the CPU/DSP transmits a trip signal through the communication backplane or field/process bus to the output module, then the operational command is delivered to the circuit breaker, but delays are introduced in the communication process causing the circuit breaker to be tripped at the wrong point in time

Engineering Contradiction:
Improveaccuracy of operational commandsVSAvoidmessage transfer time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by calculating the point in time when the operational command should be executed, taking into account the known message transfer time. The CPU/DSP determines the optimal switching point in advance and schedules the command transmission accordingly, so that despite the communication delay, the circuit breaker operates at the correct point on the voltage or current wave.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the control device uses internal time for synchronization, then the operational commands are coordinated within the control device, but the accuracy is reduced due to internal processing delays and communication delays

Engineering Contradiction:
Improvesynchronization capabilityVSAvoidtiming accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent uses an intermediary approach by introducing a calculated time offset that mediates between the internal processing time and the desired external switching time. This offset acts as a compensation mechanism that bridges the gap caused by internal delays, allowing the system to maintain synchronization capability while achieving accurate timing despite the presence of processing and communication delays.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2681822B1A control device for controlling a circuit breaker, and methods
Publication Date: 2019.07.03 ABB (SCHWEIZ) AG
  • EP2681822B1 patent drawingFigure 1~2
  • EP2681822B1 patent drawingFigure 3~4

AI summary

The invention relates to a control device (4) for controlling a circuit breaker (11). The control device (4) comprises a central processing unit (7) and is arranged to communicate with an output module (9, 9') arranged to output operational commands to the circuit breaker (11). The output module (9, 9') comprises processing means (12) arranged to execute an operational command at a point of time received from the central processing unit (7). The invention also encompasses related methods.