低壓系統之並聯電容器切換暫態現象分析及防護

Protections and Analysis of Switching Transients for Shunt Capacitor in a Low Voltage System

蕭智鴻(Chih-Hung Hsiao)

指導教授 ： 周至如 ； 何金滿

中原大學/工學院/電機工程研究所/碩士(2006年)

https://doi.org/10.6840/cycu200600283

摘要

摘 要
電力電容器已被廣泛用在工廠內，通常是做功率因數改善或做諧波濾波器的用途。由於電容器容量必須隨著負載變動而改變，故電容器的切換在所難免，尤其在低壓系統中負載變動頻繁，電容器亦須隨時切換以滿足功因改善的需求，此工作最常使用自動功因調整器來做完成，而自動功因調整器對電容器的切換會產生開關突波電壓及電流，這對各種系統與設備都有不良的影響。為此，本論文使用實際低壓系統做電容器切換實驗，並且配合電磁暫態程式分析各重要接點的開關突波電流及電壓，故本文首先依照實際系統建構電磁暫態程式分析的模型，並模擬不同開關操作下之開關突波及暫態現象，模擬大、小容量電容器分別先後投入時狀況，再以實際系統操作量測結果做印證，最後在系統加裝簡單的保護元件突波吸收器來驗證其保護效果。

關鍵字

開關突波 ； 電磁暫態程式 ； 自動功因調整器

並列摘要

Abstract
The power capacitors are widely used for improving the power factor and to do harmonic filters in the industrial plants. On the low voltage systems of plant, the power factors are varied frequently due to the load variations. Thus, the capacitors should be switched frequently for satisfying the power factor improvements. For this work, the automatics power factor regulators (APFR) are usually used for the capacitors switching. The capacitors switching surge voltages and currents are inevitable produced by the actions of APFR, which usually have detrimental effects on other systems and equipments. In the thesis, the switching surge characteristics of low voltage capacitors are studied based on simulation by electromagnetic transient program (EMTP) and field test. The circuit model of a practical system with three single-tune harmonic filters is first constructed. These single-tune filters are constructed for both harmonic filtering and power factor improvements which comprise series inductors and capacitors. Based on the circuit model the EMTP simulation with respect to various switching operations. The capacitor switching surges and transient behaviors can be obtained from the simulation and the field testes for certifying the simulation result are implemented. Finally, the protection device, (surge arrestor) are used for impressing the switching surge voltages of capacitor banks (single-tune harmonic filters). Their performance are certified by simulations and field testes.

並列關鍵字

EMTP(electromagnetic transient program) ； switch surges ； APFR(Auto Power Factor Regulators)

參考文獻

[35] 陳家富,並聯電容器組切換暫態現象之探討分析, 私立中原大學電機工程學系碩士學位技術報告, 民國九十三年。

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