Bus-Controlled Contactor Interlocking Without Auxiliary Cabling
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Solution Overview
Problem
Existing locking mechanisms for contactors in communication systems are inadequate as they require de-energization, which prevents contactors from being integrated as full participants in communication systems, and result in unnecessary auxiliary switches and additional cabling, increasing complexity and installation effort.
Innovation Solution
A bus system with a control unit and data record that manages switching states of contactors, defining permissible and impermissible switching constellations, allowing contactors to be integrated as full participants by rejecting impermissible switching signals and eliminating the need for auxiliary switches and additional cabling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional interlocking mechanisms are used to prevent unsafe operation of contactors, then safety is improved, but the contactors cannot be continuously powered and integrated into communication systems
Solution Approach 1:
The patent replaces the traditional mechanical/electromechanical interlocking system (auxiliary switches, hard-wired connections) with a digital/software-based interlocking mechanism implemented in a programmable logic controller. This substitution allows contactors to remain continuously powered and integrated into communication systems while still preventing unsafe switching configurations through software logic that monitors and controls contactor states.
2Reliability
If auxiliary switches and additional cabling are used to implement interlocking, then interlocking function is achieved, but device complexity and installation effort increase
Solution Approach 1:
The patent merges the interlocking function with the existing programmable logic controller that already manages contactor operations. Instead of adding separate auxiliary switches and cabling, the interlocking logic is integrated into the controller's software, combining multiple functions (control and interlocking) into a single system and eliminating unnecessary components.
Solution Approach 2:
The patent extracts the interlocking function from the physical hardware domain (auxiliary switches and cabling) and relocates it to the digital/software domain. This extraction eliminates the need for additional physical components while maintaining the interlocking function through software-based monitoring and control of contactor switching states.
3Reliability
If de-energization is used for interlocking, then blocking of contactors is achieved, but continuous power supply for communication is prevented
Solution Approach 1:
The patent replaces the de-energization-based interlocking mechanism with a software-based blocking mechanism. The programmable logic controller uses digital logic to prevent unauthorized or unsafe switching commands from being executed, while maintaining continuous power supply to all contactors for communication system operation.
Data Source
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AI summary
The invention relates to a method for controlling the switching states of two or more contactors (S1, S2, S3) of a switchgear assembly. The method comprises the following steps: a) providing a bus system which includes a control unit and actuators controllable by the control unit as interconnected participants of the bus system via a bus line, wherein the contactors are assigned the role of actuators of the bus system; b) providing a data set in the bus system, wherein the data set contains information defining which of the switching configurations that can be formed from possible switching states of the contactors are permissible or impermissible; c) checking, in the case of an pending switching signal from the control unit, which future switching configuration the switching signal would lead to starting from a current switching configuration; and d) rejecting the switching signal if it would result in an impermissible switching configuration.