| 引用本文: | 贺 超,王 冕,陈国柱.基于下垂控制的孤岛检测方法及其改进策略[J].电力自动化设备,2015,35(6): |
| HE Chao,WANG Mian,CHEN Guozhu.Islanding detection based on droop control and its improvement strategy[J].Electric Power Automation Equipment,2015,35(6): |
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| 摘要: |
| 针对被动孤岛检测存在较大检测盲区，传统主动检测算法会对输出电流造成有功或无功扰动的不足，提出了一种基于下垂控制的孤岛检测方法。该方法将传统下垂控制器中的频率指令由常量改为逆变器并网点的实际频率。电网正常情况下，该频率指令由于电网电压的箝位作用只有微小波动；而当孤岛发生时，受并网逆变器的调节作用影响，会发生正反馈作用，逆变器实际频率迅速发生偏移，当检测到其超过限定范围时，判定为发生孤岛现象。同时，通过引入了反馈强度系数对该方法进行了改进，并且给出了改进算法孤岛检测成功的边界条件。通过对含有2台并网发电逆变器的系统进行仿真，验证了理论推导的正确性及所提出孤岛检测方法的有效性。 |
| 关键词: 下垂控制 孤岛检测 并网逆变器 频率偏移 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（51177147）；浙江省重点科技创新团队项目（2010R50021） |
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| Islanding detection based on droop control and its improvement strategy |
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HE Chao, WANG Mian, CHEN Guozhu
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College of Electrical Engineering，Zhejiang University，Hangzhou 310027，China
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| Abstract: |
| As the methods of passive islanding detection have large indetectable zone and the traditional methods of active islanding detection may cause the active or reactive power disturbance to output current，a method of islanding detection based on the droop control is proposed，which takes the actual frequency at PCC（Point of Common Coupling），instead of a constant in traditional droop control，as the frequency reference. When grid is normal，this frequency reference varies little due to the clamping effect of grid voltage；when an islanding occurs，it shifts quickly due to the positive feedback adjustment effect of the grid-connected inverter，based on which，an islanding is thus detected when the frequency reference exceeds a limit. A feedback strength coefficient is introduced to improve the proposed method and the boundary conditions of successful islanding detection are given. Simulation is carried out for a system with two grid-connected inverters to verify the correctness of theoretical derivation and the validity of the proposed method. |
| Key words: droop control islanding detection grid-connected inverter frequency shift |
