Enabling a Robust Future HVDC Grid

高压直流输电（HVDC）系统越来越多地用于能量传输。 与交流输电相比，直流输电的功率损耗更低，可以起到防火墙的作用，从而防止危险干扰在大型网络中的级联传播。这一特点促进了可再生能源的接口。 由于半导体技术的最新进展和新的电路拓扑结构，HVDC系统正在经历革命性的转变 如多电平模块化变流器（MMC），它克服了以往采用的线性换流变流器（LCC）的不足。增加的HVDC渗透导致多馈入配置，其中多个HVDC换流器馈入同一交流系统，具有不利相互作用的可能性。** 研究的长期目标是研究高压直流输电系统的新控制方法和配置，使未来的高压直流输电网更有效和更有弹性。 为了做到这一点，发现补助金将调查三个大方向。 ** 首先，本研究将尝试通过协调控制多个转换器来改善转换器的性能，无论是在多馈入还是直流电网配置中。感兴趣的一个领域将是通过协调附近转换器的控制来降低LCC转换器中换向故障的风险。由于这些现象是高度非线性的，主要的研究方法将是使用电磁暂态模拟监督蒙特卡洛模拟和非线性优化算法。** 其次，研究将调查HVDC换流器阻尼网络中危险振荡和防止不稳定的能力。将研究使用远程转换器之间的信息传输的广域控制方法。然而，重要的是要确保系统对操作点变化、信号传输延迟和通信丢失具有鲁棒性。将使用小信号建模与最近的鲁棒控制方法相结合。控制MMC的新方法，例如使用MMC电容器中存储的能量，似乎很有前途。第三，研究将探讨新的控制方法，高压直流输电已被用于疏散电力从偏远的海上发电厂和提供能源的偏远地区，如石油平台。所提出的方法将包括自主控制算法，该自主控制算法赋予转换器类似惯性的行为，以使它们以频率下降特性来操作。其他方法包括直接控制，其中转换器的锁相环正确同步。**该研究将在加拿大和其他地方实现更低的损失和弹性能源传输网络。它将与几家加拿大公用事业公司和咨询公司合作进行，从而提高它们的竞争力。*****

High Voltage Direct Current Transmission (HVDC) Systems are seeing increasing use for the transport of energy. Compared with ac transmission, dc transmission has lower power loss and can perform the role of a firewall, thereby preventing the cascading propagation of dangerous disturbances across a large network. This feature facilitates the interfacing of renewable energy resources. HVDC Systems are undergoing a revolutionary transformation due to recent advances in semiconductor technology and new circuit topologies such as the multilevel modular converter (MMC), which overcome the deficiencies of line commutated converters (LCC) used in the past. The increased HVDC penetration is resulting in multi-infeed configurations where several HVDC converters feed into the same ac system, with the potential for adverse interactions. ******The long-term objective of the research is to investigate new control methods and configurations for HVDC Transmission Systems to make the future HVDC grid more effective and resilient. In order to do this, the Discovery Grant will investigate three broad directions. ******Firstly, the research will attempt to improve converter behavior by co-ordinated control of the multiple converters, either in a multi-infeed or dc grid configuration. One area of interest will be to reduce the risk of commutation failure in LCC converters by coordinating the controls of nearby converters. As the phenomena are highly-non-linear, the primary study approach will be to use electromagnetic-transient simulation supervised by Monte Carlo simulation and non-linear optimization algorithms. ******Secondly, the research will investigate the ability of HVDC converters to damp dangerous oscillations in the network and prevent instability. Wide-area control methods will be investigated which use information transmission between remote converters. However, it is important to ensure that the system is robust to operating point changes, signal transmission latency and loss of communication. Small signal modeling coupled with recent robust control approaches will be used. Novel ways of controlling the MMCs such as using the stored energy in the MMC's capacitors appear promising.******Thirdly the research will investigate new control methods for HVDC has been used for evacuating power from remote offshore power plants and for providing energy to remote locations such as oil platforms. Proposed approaches would include autonomous control algorithms that impart inertia-like behavior to the converters to operate them with a frequency droop characteristic. Other approaches include direct control where the phase locked loops of the converters are properly synchronized.******The research will result in lower loses and resilient energy transmission networks in Canada and elsewhere. It be carried out in collaboration with several Canadian utilities and consulting companies, thereby improving their competitiveness. *****