Merging Unit Trip Instruction via Station Bus
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Solution Overview
Problem
Existing protective control systems for power systems face high costs due to the need for redundant process bus communication paths to ensure reliability, which is not feasible in all scenarios.
Innovation Solution
A protective control system that utilizes both a process bus and a station bus for communication between merging units and calculation devices, allowing trip instructions to be transmitted through either path, thereby maintaining system reliability without the need for redundant process buses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two redundant process bus communication paths are provided to ensure reliability, then system reliability is improved, but system cost increases
Solution Approach 1:
The patent merges the control signal transmission function into the station bus, which already connects merging units and IEDs. Instead of requiring a separate redundant process bus, the station bus is utilized to transmit control signals from IEDs to merging units, thereby achieving redundancy without additional infrastructure cost
Solution Approach 2:
The station bus is given a dual function: it not only performs its original automation control functions but also serves as a communication path for transmitting control signals from IEDs to merging units. This multi-functionality eliminates the need for dedicated redundant process bus infrastructure
2Reliability
If two redundant process bus communication paths are provided to ensure reliability, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The station bus is given a dual function: it not only performs its original automation control functions but also serves as a communication path for transmitting control signals from IEDs to merging units. This multi-functionality eliminates the need for dedicated redundant process bus infrastructure
Data Source
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AI summary
A protective control system includes an IED (Intelligent Electric Device) and a merging unit. The merging unit receives a current/voltage waveform signal of a power system, and outputs a digitally converted analog data to a process bus via a communication line as a serial signal. The IED is configured to be capable of transmitting a trip instruction to the merging unit using both the process bus and a station bus. The trip instruction is for outputting the trip signal. Preferably, each of the merging unit and the IED includes a switching circuit that makes switching to the station bus when an error is detected in the process bus communication. In the event of the process bus error, communication made by the process bus is switched to communication made by the station bus. Accordingly, reliability of the process bus can be improved.