Comparison of Different Frequency Controllers for a VSC-HVDC Supplied System
Comparison of Different Frequency Controllers for a VSC-HVDC Supplied System
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DOI：
10.1109/tpwrd.2008.921130
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发表时间：
2008-04
影响因子：
4.4
通讯作者：
C. Du;E. Agneholm;G. Olsson
中科院分区：
文献类型：
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作者：
C. Du;E. Agneholm;G. Olsson
研究了三种不同的频率控制器及其对VSC-HVDC供电工业系统电压扰动穿越能力的影响。实施频率控制器的想法是通过略微降低VSC输出电压频率来改善工业工厂的电能质量，因为工业过程对电压降比频率偏差更敏感。前两个控制器，频率控制器I和II，是固定频率控制器，第三个，频率控制器III，是PI频率控制器。为了比较三种不同的控制器，一个简化的VSC-HVDC和不同的负载类型的系统进行了仿真PSCAD/EMTDC。仿真结果表明，频率控制器III，VSC-HVDC供电的工业设备可以避免电压崩溃期间或之后的干扰通过降低频率。此外，随着转换器电流限制的增加，减轻电压骤降的可能性增加。对于频率控制器I和II，扰动穿越能力的程度取决于VSC-HVDC的电流限制。更高的电流限制导致更高的穿越能力。研究了电压源换流直流输电系统采用频率控制器I时，直流电容器对提高系统电压扰动容限的作用。系统电压扰动穿越能力随着直流电容或电流限制的增加而增加。
This paper studies three different frequency controllers and their effects on the voltage disturbance ride-through capability of a VSC-HVDC supplied industrial system. The idea of implementing frequency controller is to improve the power quality of industrial plants by slightly decreasing the VSC output voltage frequency since industrial processes are more sensitive to voltage drops than frequency deviations. The first two controllers, frequency controllers I and II, are fixed frequency controllers and the third one, frequency controller III, is a PI frequency controller. In order to compare three different controllers, a system with a simplified VSC-HVDC and different load types is simulated in PSCAD/EMTDC. Simulation results show that with frequency controller III, the VSC-HVDC supplied industrial plant can avoid a voltage collapse by decreasing frequency during or after disturbances. Furthermore, with an increase of the converter current limit, the possibility of mitigating voltage dips increases. For frequency controllers I and II, the extent of the disturbance ride-through capability depends on the current limit of the VSC-HVDC. A higher current limit results in a higher ride-through capability. The effect of the dc capacitor on improving the system voltage disturbance tolerance is also investigated during and after disturbances when the VSC-HVDC uses frequency controller I. The system voltage disturbance ride-through capability increases with an increase of the dc capacitance or the current limit.