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Wang X.-B.,North China Electrical Power University | Wen J.-H.,Ningxia Electrical Power Dispatching and Control Center | Li C.-Z.,North China Electrical Power University | Luo M.-L.,Ningxia Electrical Power Dispatching and Control Center | And 2 more authors.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control

It is time consuming to use the entire network to conduct setting calculation for local area. The way to narrow down the grid size for setting calculation becomes an important subject. Based on the complex network theory, the weighted power network model is formed. The buffer subsystem for setting calculation consists of the coordination region and constraint region. After determining the scope of setting calculation, we include the adjacent branches of boundaries and its end nodes in the coordination region according to remote backup protection. Furthermore, the shortest electrical path is used to determine the minimum ring network of boundaries and coordination branches. Meanwhile the substation scope is determined by the self-impedance variation rate of boundary nodes. The constraint region consists of the smallest ring structures and substation scope. Under these, the depth first search and backtracking technique are applied to form the buffer subsystem automatically. Source

Zhong H.,Tsinghua University | Xia Q.,Tsinghua University | Ding M.,Ningxia Electrical Power Dispatching and Control Center | Zhang H.,Ningxia Electrical Power Dispatching and Control Center
Dianli Xitong Zidonghua/Automation of Electric Power Systems

In the interconnected power grid with large-scale renewable energy, the renewable energy can be accommodated in a wider area if the adjustment capability of high-voltage direct-current (HVDC) tie-lines is well utilized. To this end, a new mode of HVDC tie-line operation optimization for increasing the capability of renewable energy accommodation is proposed. In the mode, the tie-line power is viewed as a resource to be optimized. On the premise of meeting all the requirements of the tie-line power adjustment, the renewable energy accommodation in the interconnected power grid can be improved by adjusting the tie-line power. A mathematical model of the HVDC tie-line operation optimization is developed with consideration given to various constraints on tie-line power adjustment, including the daily energy limit, the stair-like tie-line power curve constraint, and the constraint that no adjustment in the opposite direction of the tie-line power shall be made within a short period of time. Case studies are conducted based on the actual operational data of a transregional HVDC transmission channel in China. The results have validated the effectiveness of the mode proposed. © 2015 State Grid Electric Power Research Institute Press. Source

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