Protection systems and protection methods

The protection system uses synchronized AC voltage and current sampling by transmission line relays to quickly determine fault direction and perform backup busbar protection, addressing delays and costs in existing systems.

JP7864059B2Active Publication Date: 2026-05-22MITSUBISHI ELECTRIC CORP
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
MITSUBISHI ELECTRIC CORP
Filing Date
2022-11-18
Publication Date
2026-05-22

AI Technical Summary

Technical Problem

Existing power system protection systems face delays in removing accidents from busbars due to backup protection devices, leading to expanded power outages, and require costly dedicated communication equipment for protection relays.

Method used

A protection system comprising multiple transmission line protection relays and a busbar protection device that samples AC voltage and current synchronously, allowing each relay to determine fault direction and perform backup busbar protection functions when the primary device fails, using a current differential relay method.

Benefits of technology

Enables rapid fault determination and simplified busbar protection by transmission line relays, reducing the need for costly dedicated communication equipment and minimizing power outages.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

To substitute a bus-bar protection function using a simple method when the bus-bar protection function becomes inoperative.SOLUTION: In a protection system 1 of a power system 4, each of a plurality of power transmission line protection relays TPRs performs accident determination of a corresponding power transmission line TL based on sampling values of AC voltage and AC current sampled synchronously with each other. A bus line protection device BPD performs accident determination of a bus line BL based on the sampling values of the AC current received from the plurality of power transmission line protection relays TPRs by current differential relay method. Each of the plurality of power transmission line protection relays TPRs performs determination of whether or not there has been an accident in a power system 4 and direction determination to determine whether an accident point is on the bus line side or the corresponding power transmission line side, in the case the bus line protection device BPD is faulty. A power transmission line protection relay TPR1 at a master station determines that the accident has occurred on the bus line BL if results of the direction determination of the plurality of power transmission line protection relays TPRs are all on the bus line side.SELECTED DRAWING: Figure 1
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