Distributed Waveform Recording in Power Distribution Systems
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Solution Overview
Problem
Current power distribution systems face limitations in waveform recording due to memory constraints, lower sampling rates, and timing inaccuracies, which hinder effective fault analysis and increase costs with dedicated Digital Fault Recorders.
Innovation Solution
A distributed waveform recording method that communicates sampled measured value data through a process bus, triggers waveform recording based on event detection by Intelligent Electronic Devices (IEDs) at different hierarchical levels, using network time synchronization to ensure accurate synchronization and efficient resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated Digital Fault Recorder (DFR) is used for waveform recording, then the sampling rate and recording duration are improved, but the system cost and device complexity increase
Solution Approach 1:
The patent makes existing protection and control IEDs perform multiple functions including waveform recording alongside their primary protection and control functions. This eliminates the need for dedicated DFR devices while maintaining waveform recording capabilities through the existing IED infrastructure.
Solution Approach 2:
The patent combines the waveform recording function with existing protection and control IEDs by integrating the recording capability into these devices. This merging approach consolidates multiple functions into single devices, reducing overall system complexity and eliminating dedicated recording hardware.
2Device complexity
If protection IEDs are used for waveform recording as a secondary function, then the system cost is reduced, but the waveform storage space and sampling rate are limited
Solution Approach 1:
The patent transitions from centralized waveform storage in single IEDs to distributed storage across multiple IEDs in the hierarchy. This dimensional change in storage architecture allows the system to aggregate storage capacity across multiple devices, effectively increasing total waveform storage capacity while using existing resources.
Solution Approach 2:
The patent segments the waveform recording function across multiple IEDs distributed throughout the power distribution hierarchy. Each IED stores waveform data locally, and the distributed architecture allows the system to leverage the combined storage capacity of all participating IEDs rather than relying on a single centralized recorder.
3Productivity
If different IEDs record waveforms independently, then the local recording capability is improved, but the timing synchronization accuracy deteriorates
Solution Approach 1:
The patent implements a trigger mechanism where GOOSE messages carry trigger information that propagates through the IED hierarchy. When a fault is detected at any level, the trigger message is forwarded down the hierarchy, ensuring all IEDs start recording at the precise moment of fault occurrence. This feedback-based triggering ensures synchronized recording across distributed IEDs.
Solution Approach 2:
The patent pre-configures the IED hierarchy with GOOSE communication channels and trigger forwarding capabilities before faults occur. The system is prepared in advance to rapidly propagate trigger messages and initiate synchronized recording across all levels, eliminating timing delays that would occur if synchronization had to be established after fault detection.
4Productivity
If the IED hierarchy is utilized for distributed waveform recording, then the resource utilization is improved, but the coordination complexity increases
Solution Approach 1:
The patent implements dynamic trigger forwarding where the behavior of each IED changes based on whether it receives a trigger message. Normal IEDs forward triggers down the hierarchy, while recording IEDs activate their recording functions. This dynamic response pattern simplifies coordination compared to static configurations, as each IED automatically adapts its behavior based on real-time conditions.
Solution Approach 2:
Each IED in the hierarchy autonomously determines whether to forward triggers or activate recording based on its configuration and received messages. The IEDs self-organize into a coordinated recording system without requiring external control, with each device independently managing its own trigger forwarding or recording activation based on pre-configured parameters.
Data Source
AI summary
An exemplary method and apparatus are directed to distributed waveform recording for fault monitoring and analysis of a fault condition in a power distribution system. One or more instrument transformers along with merging units and a plurality of Intelligent Electronic Devices (IEDs) distributed in a plurality of hierarchical levels. The distributed waveform recording corresponds to a fault event at different levels in the power distribution system data is carried out by at least two devices configured to detect an event for recording and perform waveform recording. The data used for waveform recording and the data for detection of the event are based on a single stream of the sampled measured value data and are thereby are time synchronized.