Single Phase Fault Isolation with Load Estimation
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Solution Overview
Problem
In electric power distribution networks, existing fault isolation methods often result in unnecessary power outages for multiple customers due to the inability to isolate faults at the precise phase level, leading to inefficient restoration processes.
Innovation Solution
A system and method utilizing an electronic processor to receive fault indications, identify the correct isolation devices, and perform single-phase fault isolation and restoration by estimating current loads and selecting intermediate isolation devices to minimize power disruptions, allowing for precise control of power restoration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all three phases are isolated in response to a detected fault, then fault isolation is achieved, but power is interrupted for all customers on the affected transmission line including non-affected portions
Solution Approach 1:
The transmission line is divided into multiple line segments between isolation devices, and the fault is isolated to only the specific segment where it occurs. This allows other segments to remain operational, delivering power to customers without interruption while the faulted segment is isolated and repaired.
2Difficulty of detecting and measuring
If isolation devices are used to detect and isolate faults, then fault detection capability is provided, but unnecessary power outages occur for multiple customers
Solution Approach 1:
The system applies different treatment to different phases and line segments based on where faults are detected. Only the specific phase and line segment containing the fault are isolated, while other phases and segments continue operating normally, minimizing power outage duration for affected customers.
3Measurement precision
If current monitoring is installed on all line sections, then precise load measurement is achieved, but system complexity and cost increase
Solution Approach 1:
The system uses existing current monitoring infrastructure at isolation devices for multiple purposes: fault detection, load measurement, and restoration planning. This eliminates the need for separate current monitoring equipment on every line section, reducing system complexity while maintaining measurement precision where needed.
Data Source
AI summary
A processor receives an indication of a fault from a first isolation device. The processor sends a first open command to a downstream isolation device downstream of the fault, identifies a tie-in isolation device, and identifies a line section without current monitoring positioned between the tie-in isolation device and the downstream isolation device. The line section has a plurality of line segments, each having a load rating. The processor receives incoming and exiting current measurements for the line section and estimates a first current load for each of the line segments in the line section based on the incoming and exiting current measurements and the load ratings. The processor selects an intermediate isolation device between the tie-in isolation device and the downstream isolation device based on the first current loads, sends a second open command to the intermediate isolation device, and sends a close command to the tie-in isolation device.