电测与仪表
電測與儀錶
전측여의표
ELECTRICAL MEASUREMENT & INSTRUMENTATION
2014年
17期
67-72
,共6页
姜明磊%刘曦%王伟%辛苑
薑明磊%劉晞%王偉%辛苑
강명뢰%류희%왕위%신원
三相四线制微网%三相不平衡%下垂控制%两级控制%单相独立控制
三相四線製微網%三相不平衡%下垂控製%兩級控製%單相獨立控製
삼상사선제미망%삼상불평형%하수공제%량급공제%단상독립공제
three-phase four-wire microgrid%three-phase imbalance%droop control%two-level control%single-phase independent control
三相四线制低压微网中，由于接入大量单相负荷，常引起三相不平衡情况。而传统控制方法在三相不平衡情况下不能有效控制低压微网在孤岛运行时的电压和频率稳定。针对三相四线制低压微网特点，设计了单相电压独立控制的下垂控制方法。论文首先在考虑低压微网的阻抗特性主要呈阻性的情况下，采用了改进的下垂控制方法，并设计了单相电压独立控制，使控制系统能够运行在三相不平衡负荷下；然后设计两级控制对低压微网孤岛运行时的频率和电压进行控制，并对误差量进行修正；最后根据设计的控制策略进行系统仿真分析验证方法有效性。在PSCAD平台上通过对搭建的小型低压微网算例仿真，验证了基于改进下垂控制的单相独立控制方法的有效性以及能够实现低压微网孤岛运行时电压频率稳定的要求，所设计的方法能够达到在三相不平衡情况下的控制目标。
三相四線製低壓微網中，由于接入大量單相負荷，常引起三相不平衡情況。而傳統控製方法在三相不平衡情況下不能有效控製低壓微網在孤島運行時的電壓和頻率穩定。針對三相四線製低壓微網特點，設計瞭單相電壓獨立控製的下垂控製方法。論文首先在攷慮低壓微網的阻抗特性主要呈阻性的情況下，採用瞭改進的下垂控製方法，併設計瞭單相電壓獨立控製，使控製繫統能夠運行在三相不平衡負荷下；然後設計兩級控製對低壓微網孤島運行時的頻率和電壓進行控製，併對誤差量進行脩正；最後根據設計的控製策略進行繫統倣真分析驗證方法有效性。在PSCAD平檯上通過對搭建的小型低壓微網算例倣真，驗證瞭基于改進下垂控製的單相獨立控製方法的有效性以及能夠實現低壓微網孤島運行時電壓頻率穩定的要求，所設計的方法能夠達到在三相不平衡情況下的控製目標。
삼상사선제저압미망중，유우접입대량단상부하，상인기삼상불평형정황。이전통공제방법재삼상불평형정황하불능유효공제저압미망재고도운행시적전압화빈솔은정。침대삼상사선제저압미망특점，설계료단상전압독립공제적하수공제방법。논문수선재고필저압미망적조항특성주요정조성적정황하，채용료개진적하수공제방법，병설계료단상전압독립공제，사공제계통능구운행재삼상불평형부하하；연후설계량급공제대저압미망고도운행시적빈솔화전압진행공제，병대오차량진행수정；최후근거설계적공제책략진행계통방진분석험증방법유효성。재PSCAD평태상통과대탑건적소형저압미망산례방진，험증료기우개진하수공제적단상독립공제방법적유효성이급능구실현저압미망고도운행시전압빈솔은정적요구，소설계적방법능구체도재삼상불평형정황하적공제목표。
In the three-phase four-wire low-voltage microgrid, the large amount of single -phase load will always cause three-phase imbalance .In such situation , the traditional control method will not keep the voltage and frequen-cy stable effectively when operating in low -voltage microgrid in the island mode .According to the characteristics of the three-phase four-wire low-voltage microgrid , a single-phase independent control has been proposed based on the droop control.Firstly, considering the impedance characteristic of the low voltage microgird mainly appears as re-sistance , the improved droop control method is adopted , and a single-phase independent control strategy has been designed to ensure the normal operation of the control system under the unbalanced loads .Then a two-level control strategy has been proposed to control the voltage and frequency in the microgrid during the island mode .Finally, a simulation analysis based on the proposed method is used to prove the effectiveness .A microgrid is set up on PSCAD , and the effectiveness of the single -phase control strategy will be verified based on the improved droop control .The proposed method can also meet the requirement of the voltage and frequency stability in the island mode .At the same time, the control method proposed in this paper can achieve the control objective under the condition of unbalanced three-phase .
