分散式電力系統之不平衡電壓補償方法

An Unbalance Voltage Compensation method for the Distributed Generation System

陳建安(Chien-An Chen)

指導教授 ： 鄭博泰 ； 鍾太郎

國立清華大學/電機資訊學院/電機工程學系/碩士(2007年)

https://doi.org/10.6843/NTHU.2007.00679

摘要

近年來由於再生能源等小型發電源的普及，而這些小型發電源連結成分散式發電系統的型態已成為一種新興的趨勢。 在分散式發電系統中，為了解決各分散式發電系統間電力潮流分配的問題，實功率-頻率與虛功率-電壓振幅下降控制器已被應用在電力系統與小型發電源作為介面的反流器中。然而，當系統中有不平衡負載，前述的功率分配控制器無法有效率的分配不平衡的電流。儘管已有相關的研究針對不平衡負載作電壓，然而不平衡電流的分配問題仍無法獲得解決。
因此這此論文中提出一個負序虛功率-負序導納的下降控制器，此控制器能使反流器產生負序導納，並根據各個反流器所輸出的負序功率來調整其導納，以達到在不需通訊的情況下，自動分配不平衡電流以及抑制不平衡電壓的功能。此控制器能順利的與實功率、虛功率分配下降整合運作分配實功、虛功、負序虛功。使得分散式電力系統在不平衡負載的情況下，在系統中各反流器間仍能依據其額定，自動的分配其輸出能量。
為了驗證所提出的控制器，相關的硬體實驗與模擬將會在此論文中架設並近一步的分析討論。

關鍵字

分散式發電系統 ； 不平衡負載 ； 下降控制器 ； 反流器

並列摘要

As regeneration sources become more and more popular, distributed generation (DG) system which integrates these small power sources has become a trend for future power system. In DG system, to balance power flow from each microsource, the power-frequency droop and reactive power-voltage droop controllers are applied in converters which interface the microsources. However, when the system is connected with imbalanced load, the droop controllers can not equally distribute the unbalanced current. Previous studies about line imbalance can maintain symmetrical line voltages under load imbalance, yet the distribution of the unbalanced current is not addressed in these literatures. Consequently, the unbalanced workload distribution among converters is still a problem to be solved.
To approach this problem, a droop controller is proposed to share the unbalanced current in DG system. In this controller, a negative sequence conductance G is introduced in each converter, and the conductance command will be determined by the negative sequence reactive power Q— of each converter. Through the droop control of the conductance, the unbalanced current will be shared among converters without communication, and also the implementation of the conductance will reduce the unbalanced voltage level. The proposed controller can be seamlessly combined with P-f droop and Q-v droop controllers to share the power, reactive power and negative sequence reactive power between converters. Therefore, an automatically energy distribution proportional to the capacity of each converter can thus be achieved in the distributed generation system under imbalanced loading.
To realize the control method, hardware test and simulation of DG system will be constructed and analyzed in the thesis.

並列關鍵字

distributed generation system ； unbalanced load ； droop controller ； inverter

參考文獻

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