Zone Selective Interlocking Link Fault Detection
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Solution Overview
Problem
Existing directional zone selective interlocking (DZSI) systems in power distribution fail to promptly detect faults in communication links between switches of different types, leading to potential serious losses due to unreliable signal transmission and lack of automatic fault inspection.
Innovation Solution
A zone selective interlocking device with a query signal receiving branch and communication signal sending/receiving branches that switch between states to detect link faults within preset timeslots, enabling automatic inspection and reliable transmission of DZSI signals across switches of different types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DZSI systems use communication links between switches of different types, then the system can achieve directional zone selective interlocking functionality, but the reliability of signal transmission deteriorates due to lack of automatic fault detection
Solution Approach 1:
The patent implements preliminary fault detection by sending query signals through communication links before actual DZSI signal transmission. The system proactively tests the communication link between switches of different types using dedicated query signal branches, identifying potential faults before they affect the reliability of DZSI signal transmission. This preliminary action ensures that the communication path is verified to be functional and reliable.
Solution Approach 2:
The patent establishes a feedback mechanism where the receiving switch responds to query signals sent by the transmitting switch. The query signal receiving branch monitors the communication link by sending test signals and receiving acknowledgments. If no response is received within a preset time, the system identifies a fault in the communication link, providing continuous feedback on the reliability of the communication path between switches of different types.
2Device complexity
If DZSI systems transmit signals without automatic inspection, then the device complexity is reduced, but the loss of time increases due to undetected faults leading to serious losses
Solution Approach 1:
The patent merges the fault detection function with the existing DZSI signal transmission infrastructure by utilizing the same communication ports and adding dedicated query signal branches. The query signal transmitting branch is integrated into the existing switch structure, sharing physical resources with the DZSI signal transmission path. This merging approach enables automatic fault inspection without significantly increasing device complexity, as the detection and transmission functions coexist within the same hardware framework.
3Adaptability or versatility
If switches of different types communicate in mixed DZSI systems, then the versatility of the system is improved, but the difficulty of detecting and measuring faults increases
Solution Approach 1:
The patent implements a universal query signal mechanism that can detect faults in communication links between any types of switches. The query signal transmitting and receiving branches are designed to work with different switch types (e.g., ACB and MCCB) using standardized communication protocols. The fault detection function is made universal by enabling any switch in the mixed system to send and receive query signals, regardless of the specific switch types involved, thereby simplifying fault detection across diverse hardware configurations.
Data Source
AI summary
A zone selective interlocking device includes a first port, a second port, an input bus, an output bus and a query signal receiving branch. The first and second port each are switchable between two states, connected to the input bus and connected to the output bus, and the zone selective interlocking device is operable in a first mode. In the first mode, the query signal receiving branch is turned on. Within a preset timeslot, a link fault query signal is permitted to be inputted to the query signal receiving branch through the first port, while a link fault query signal is prevented from being inputted to the query signal receiving branch through the second port. Based on whether a link fault query signal is received within the timeslot, a judgment is made on whether a fault has occurred in a communication link connected to a corresponding port.