Study of transmission capacity calculation method under high voltage security constraint

2015 ◽  
Author(s):  
Linlin Wu ◽  
Hui Liu ◽  
Jin-gang Yang ◽  
Kai Bai ◽  
Haojing Wang
Keyword(s):  
High Voltage ◽  
Calculation Method ◽  
Transmission Capacity ◽  
Voltage Security ◽  
Capacity Calculation ◽  
Security Constraint

scholarly journals A Topology Analysis-Based MMC-HVDC Grid Transmission Capacity Calculation Method

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 822
Author(s):  
Xiao Yu ◽  
Bing Zhao ◽  
Shanshan Wang ◽  
Tiezhu Wang ◽  
Lu Zhang
Keyword(s):  
Calculation Method ◽  
Transmission Capacity ◽  
Affecting Factors ◽  
Multilevel Converter ◽  
Topology Analysis ◽  
High Voltage Direct Current ◽  
Operation Modes ◽  
Capacity Calculation ◽  
Power Limits ◽  
Power Dispatching

Modular multilevel converter-based high voltage direct current (MMC-HVDC) has a broad application prospect in renewable energy transmission. With the development of converter capacity, the transmission capacity calculation for MMC-HVDC grids becomes important for power dispatching. The existing method depends on manual work and is suitable for a simple grid. However, as the grid structure and operation modes become more and more complex, it becomes difficult to calculate the transmission capacity of different operation modes for an MMC-HVDC grid. This paper analyzed and simplified affecting factors and basic topologies. On this basis, a topology-based MMC-HVDC grid transmission capacity calculation method is proposed. First, an MMC-HVDC grid is divided into sending end grid, transmission section lines, and receiving end grid. Then the power limits of these three parts are calculated. Finally, the transmission capacity is determined by analyzing the connection mode of these three parts. This method can be adapted to any kind of MMC-HVDC grid and can be easily programmed.

Calculation method of winding eddy‐current losses for high‐voltage direct current converter transformers

2016 ◽  
Vol 10 (6) ◽  
pp. 488-497 ◽  
Author(s):  
Yaqing Liu ◽  
Dandan Zhang ◽  
Zhenbiao Li ◽  
Qinqing Huang ◽  
Bin Li ◽  
...  
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Eddy Current ◽  
Calculation Method ◽  
Eddy Current Losses ◽  
High Voltage Direct Current ◽  
Current Converter

scholarly journals Study on Flexural Bearing Capacity Calculation Method of Enclosure Pile with Partial Excision in Deep Foundation Pit

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Mingfeng Lei ◽  
Linghui Liu ◽  
Yuexiang Lin ◽  
Jin Li
Keyword(s):  
Flexural Strength ◽  
Bearing Capacity ◽  
Calculation Method ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Theoretical Derivation ◽  
Deep Foundation Pit ◽  
Practical Engineering ◽  
Capacity Calculation ◽  
Partial Excision

During deep foundation pit construction, the structural clearance intrusion, which is caused by the complex formation conditions and the inefficient drilling equipment, is usually detected due to the vertical deviation of piles. To meet construction requirements, pile parts intruding into the structural clearance are supposed to be excised. However, the sectional flexural strength of the pile is bound to decrease with partial excision, which would reduce the bearing capacity of the enclosing structure during construction. In this paper, a theoretical derivation of the normal sectional flexural strength of the partially excised circular pile is proposed. The derivation adopts the assumption of the plane section and steel ring equivalence and can be solved by the bisection method. Furthermore, the calculation method is applied to the pile evaluation of a practical engineering; also, the method is verified by the numerical method. The application results show that the excision of rebar and pile’s sectional area will cause a rapid linear decline in the sectional flexural strength. After excising 18 cm radial thickness of the circular pile (ϕ800 mm) and 6 longitudinal rebars, the sectional flexural strength of the pile decreases to 58% from the origin, which cannot meet the support requirement. The analysis indicates that pile reinforcements must be carried out to maintain the construction safety.

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