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为了解决下垂控制无法实现功率无差控制的缺陷以及方便直流电网的分区管理，设计直流电网潮流的分级分区控制。该控制包括集中控制和本地控制两部分。集中控制利用集控中心的潮流计算程序计算得到的各换流站节点的电压，以直流电压计算值修正各下垂控制站的直流电压参考值从而实现各换流站的功率无差控制。本地控制不依赖于集控中心，包括积差控制、分区控制和联络线功率紧急支援控制。积差控制利用本地监测量修正下垂控制的电压参考值实现换流站功率无差控制。分区控制用于将本区内的功率不平衡限制在本区内，防止对区外直流电网功率产生影响。联络线功率紧急控制用于调控某区内所有换流站的有功功率，为其他区域提供紧急功率支援从而将紧急功率支援任务分散到各个换流站上。所设计的控制器在一个七站两区域直流电网上得到了验证。“,”To solve the steady state DC power tracking error in droop control and to enable flexible regional regulation of a DC grid, a hierarchical and regional power flow control was designed. The control is composed of centralized control and local control. The centralized control uses a DC power flow algorithm located at power dispatching center to calculate DC voltage at each converter to adjust the DC voltage reference value of droop control so as to achieve zero steady state power tracking error. The local control does not depend on control center. It is composed of error-accumulation control, regional control and emergent power support control. The error-accumulation control uses local measurements to adjust voltage references of droop control so as to eliminate the power tracking error in steady state. The regional control is used to restrain the power imbalance within local DC grid so as not to affect external DC grid. The emergent power support control is used to adjust power of all the converters of one region to sup-port emergent DC power to another region. Simulations on PSCAD/EMTDC of a 7-terminal two region DC grid con-firmed the proposed control strategies.