大规模交直流系统电磁暂态仿真和稳定控制技术研究

发布时间：2018-01-09 14:30

本文关键词：大规模交直流系统电磁暂态仿真和稳定控制技术研究　出处：《浙江大学》2014年博士论文　论文类型：学位论文

【摘要】：我国能源资源与电力需求之间的逆向分布客观上决定了我国要实施“西电东送、南北互供、全国联网”电力发展战略。区域电网互联和高压直流输电(High Voltage Direct Current, HVDC)技术在电力系统中的广泛应用使我国电力系统朝着大规模、跨大区、交直流互联方向发展。交直流互联使得大规模交直流电力系统的动态行为更加复杂,传统机电暂态仿真技术已不能完全满足要求；另外,在新特性下大规模交直流电力系统的安全稳定运行面临更多的挑战,这对电网安全稳定控制技术提出了更高的要求。为此,本文围绕大规模交直流电力系统电磁暂态仿真和稳定控制技术进行了深入的研究,完成了以下工作： (1)提出了一种适用于大规模交直流电磁暂态仿真的动态等值方法。该方法在等值的过程中保留500kV主干网架、重要的直流线路以及它们之间的交流联系,并保证等值发电机对主干网架支撑的短路电流与原网络相同；在等值过程中不需要解开500kV和220kV电压等级之间的电磁环网,等值后的系统可以用于在电磁暂态仿真平台中详细研究大规模交直流系统间的相互作用特性。以南方电网交直流系统为算例表明该动态等值方法较好地保留了大规模交直流系统的动态特性。 (2)研究了一种基于PSCAD/EMTDC的大规模交直流系统电磁暂态仿真建模方法。给出了机电暂态仿真程序PSS/E和电磁暂态程序PSCAD/EMTDC中元件模型的对应关系以及PSCAD/EMTDC中元件的自定义方法。该方法已成功应用于PSCAD/EMTDC中南方电网交直流系统的搭建,建模方法的有效性通过PSS/E和PSCAD/EMTDC的时域仿真对比得到了验证。最后通过分析交流不对称故障对直流系统运行乃至整个交流系统的影响,阐明了在研究大规模交直流系统时机电暂态仿真程序的局限性和采用电磁暂态仿真程序的必要性。 (3)提出了一种提高交直流电力系统暂态稳定性的HVDC广域鲁棒控制器设计方法。该方法考虑直流系统简化模型引起的误差、信号时滞及各种干扰给附加控制器的设计增加的不确定因素,首先根据区域惯量中心(Center of Interia, COⅠ)的运动方程和滑模控制设计方法确定滑模切换面,然后利用李雅普诺夫稳定性定理保证系统在不确定因素存在的情况下渐近稳定,最后为了将HVDC广域鲁棒控制设计方法推广到大规模交直流电力系统中,提出了直流系统一机组控制敏感指标。以4机2区域交直流系统、多馈入交直流系统和浙江电网为算例表明了HVDC广域鲁棒控制器的有效性。 (4)提出了一种基于多工况综合留数及H2/H,混合控制的直流附加阻尼控制的鲁棒设计方法。该方法综合考虑了控制器安装地点和反馈信号组合方案对主导模式的可观可控性、对其它模式的耦合作用和对多种运行工况的鲁棒性三个因素,提出了多工况综合留数指标来确定最优方案,并通过比较所设计的控制器的H2/H∞综合性能验证了多工况综合留数指标的有效性。最后,在一个大规模交直流混联系统多种运行工况多种故障下验证了基于多工况综合留数和H2/H∞的直流附加阻尼控制鲁棒设计方法的有效性。 (5)分析了大规模交直流系统中直流系统实际输送功率受直流系统换流站交流母线电压波动的影响情况。首先根据直流系统Ud-Id特性曲线分析得到两端换流站交流母线电压变化时直流系统的各种可能的运行模式,再针对每种运行模式计算得到此时直流系统的实际输送功率。研究结果表明,只有两端换流站交流母线电压维持在一定电压水平,才能使直流系统实际输送功率达到紧急功率支援指令值。
[Abstract]:Reverse distribution between energy resources and power demand of China decided our country should implement the "west to East, North South mutual supply, a national network of electric power development strategy. The regional power grid interconnection and HVDC (High Voltage Direct Current HVDC) technology is widely used in electric power system, the power system of our country in a large, cross regional, AC / DC direction. The dynamic behavior of AC-DC interconnected large-scale AC / DC power system is more complex, the traditional electromechanical transient simulation technology can not satisfy the requirements; in addition, the safe and stable operation of large-scale AC / DC power system in the new characteristics of the face more challenges, the security and stability of power grid control technology has put forward higher requirements. Therefore, this paper focuses on large-scale AC / DC power system electromagnetic transient simulation and stability control technology is studied, end The following work has been made:
(1) dynamic equivalence method is proposed for large-scale AC / DC electromagnetic transient simulation. The method retains the 500kV skeleton in the equivalent process between the DC line and their important communication links, and ensure that the short circuit current equivalent generator on the trunk network support is the same as the original network; the equivalent process do not need to unlock the electromagnetic loop network between 500kV and 220kV voltage level, the equivalent system can be used in the electromagnetic transient simulation platform in detail based on large-scale interaction characteristics of DC system. In AC DC system for example shows that the dynamic equivalence method effectively keeps the dynamic characteristics of the large scale AC / DC systems.
(2) of a PSCAD/EMTDC electromagnetic transient simulation modeling method of large-scale AC / DC system. Based on the given correspondence between the elements of electromechanical transient simulation program PSS/E and electromagnetic transient program PSCAD/EMTDC model and method of the custom PSCAD/EMTDC components. This method has been successfully applied to build AC / DC system in PSCAD/EMTDC, effectiveness the modeling method obtained by time domain simulation comparison between the PSS/E and PSCAD/EMTDC verification. Finally through the analysis of AC asymmetric fault impact on the operation of HVDC system and the communication system, expounded the large-scale AC / DC system in electromechanical transient simulation program and the limitation of the electromagnetic transient simulation program is necessary.
(3) presents a method to improve the design method of robust controller of HVDC wide area transient stability of AC / DC power system. This method takes into account the error caused by the simplified model of DC system, signal delay and uncertainty interference to design additional controller increase, according to the regional center of inertia (Center of Interia, CO 1) to determine the sliding mode the switching surface and motion equation of sliding mode control design method, then using Lyapunov stability theorem guarantees the system asymptotically stable in the uncertain factors exist, finally to the HVDC wide area robust control design method is extended to large-scale AC / DC power system, DC system control unit is put forward on the 4 machine 2 sensitive indicators. Regional AC / DC system, multi infeed HVDC system and Zhejiang power grid show the effectiveness of the wide area robust controller with HVDC as an example.
(4) proposed a multi condition comprehensive residue and H2/H based on the robust design method of HVDC damping control of hybrid control. This method considers the controller mounting locations and feedback signals of the dominant mode of combination of observability and controllability, coupling to other models with multiple operating conditions and the robustness of the three a factor, put forward a comprehensive multi residue index condition to determine the optimal scheme, and the effectiveness of comprehensive multi residue index condition is verified by comparing the H2/H controller design of the comprehensive performance. Finally, in a large scale AC-DC hybrid system under various operating conditions of a variety of fault to verify the effectiveness of HVDC damping for the H2/H residue and the comprehensive condition of robust control design method based on.
(5) analysis of the impact of large-scale AC / DC system and DC system in the actual transmission power by the voltage fluctuation of DC system converter AC bus. Firstly, according to the characteristics of Ud-Id curve analysis of DC system running mode converter AC bus voltage change at both ends of the DC system may, for each kind of operating mode to calculate the actual transmission power at DC the system is obtained. The results of the study show that only two converter bus voltage is maintained at a certain voltage level, in order to make the actual transmission power of the HVDC system to achieve emergency power support command value.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM721.1

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