二次變電所主變壓器停電時未切離負載下逕行所內轉供之暫態分析

Analysis of Transfer Switching Transients under Load Condition when the Main Transformer Out of Service in the Secondary Substation

游宏益(Hung-Yi Yu)

指導教授 ： 周至如 ； 洪穎怡

中原大學/工學院/電機工程研究所/碩士(2008年)

https://doi.org/10.6840/CYCU.2008.00379

摘要

本文以ATP/EMTP電磁暫態模擬程式，模擬一典型之11.4kV配電系統，在二次變電所主變壓器發生事故停電時，逕行投入連絡斷路器轉供瞬間之暫態突波電壓與電流響應，藉以評估電壓突波是否會對線路上或用戶的設備造成危害，以及衝擊電流是否會造成提供支援之主變壓器亦跳脫，而擴大事故停電範圍，並藉此評估當某一主變壓器於發生事故停電時，其他主變壓器容量剩餘裕度允許情況下，逕行投入連絡斷路器轉供之可行性，以提昇恢復供電效率，縮短停電時間。
經由評估結果將提出轉供之程序與配套措施，利用餘裕度指數判斷是否逕行投入連絡斷路器轉供，而為了快速判斷餘裕度是否允許，各變電所可依其負載特性訂定其「餘裕度指數」，只備用容量大於此指數，就可進行後續轉供之操作，不過對於較敏感的系統，本報告提出運轉策略是將饋線以其供電持續性區分成兩個群組，一為急迫性群組，另一為一般性群組，前者需要有高度的供電持續性，如其他主變壓器尚有足夠備用容量時，必須優先復電，其切換程序是先將一般性群組的饋線切離，再投入連絡斷路器，最後再依剩餘備用容量多寡，逐步對一般性群組復電，此可兼顧急迫性負載的快速復電及降低開關突波電壓電流之衝擊，以提昇整體系統的供電可靠度。

關鍵字

主變壓器 ； 負載轉供 ； 電磁暫態模擬程式

並列摘要

In this report, the transient behaviors of surge voltages and currents due to transfer switching when a main transformer in the secondary substation are analyzed by simulating a typical 11.4kV distribution system based on the package of alternative transient program / electromagnetic transient program（ATP/EMTP）. The damages may be occurred on the equipments of feeders and customers are evaluated based on the analysis results of surge voltages and currents, and the affection of other main transformers for supporting services to trip out will be surveyed. Furthermore, the feasibility of transfer switching under load condition when other main transformers still have enough spare capacities in assessed. Finally, based on the assessment results, the suitable procedure and measures for implementing transfer switching under load condition are proposed, where an index namely spare capacity index（SCI）for a substation can be determined based on its load characteristics. For conventioned cases, if the spare capacity is larger than SCI, then rapid transfer switching can be implemented. For those sensitive systems, however, the feeders are categorized into two groups. For the sensitive systems, however, the feeders are categorized into two groups namely urgent group and normal group based on the requirement of service continuity. The feeders of urgent group need high service continuity such that they will be first restored to service if the other main transformers still have sufficient spare capacities. For this, the operation procedure is defined as that the feeders of normal group should be first opened when their main transformer out of service, then the tie breaker is closed for energizing the feeders of urgent group to service, after that, the feeders of normal group are energized gradually according to the amount of left spare capacities of other main transformers. Under such operation procedure, both of rapid restoration for urgent loads and reducing the impacts of switching surge voltages and currents are all considered for increasing the reliability of the whole system.

並列關鍵字

Main Transformer ； alternative transient program / electromagnetic transie ； Load Trnasfer

參考文獻

[8] NEMA CP1.1988, Shunt Capacitors.

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