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Shen W.,Tsinghua University | Wu W.,Tsinghua University | Zhang B.,Tsinghua University | Hao J.,Henan Electrical Power Dispatching and Communication Center
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

It is a time-consuming task to manually edit the power grid one-line diagram in an EMS. An automatic diagram generating method is proposed. The automatic diagram generation problem can be divided into two sub-problems: the substation placement and transmission lines layout. The gravitation-repulsion method is used to optimize substation placement. This method can efficiently calculate a good scheme. Based on this initial scheme, a genetic algorithm is also used to revise the solution. To solve the transmission lines layout problem, the labyrinth exploration method is used to make the lines connecting two substations straight and even. The software developed based on the proposed method has been embedded in a commercial grade EMS and proved practical. ©2010 State Grid Electric Power Research Institute Press.


Zhou H.,Hohai University | Huang X.,Henan Electrical Power Dispatching and Communication Center | Wu L.,Hohai University | Ju P.,Hohai University
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

In dynamic equivalents of power systems, if the excitation systems of the coherent generators are of the same type, the equivalent excitation system has the same type and the same model, and the equivalent parameters could be obtained with the weighted summation. However, the excitation systems of the coherent generators may be different. For this case, the uniform stand transfer function as the model of equivalent excitation system are proposed, and the parameters of the equivalent excitation systems are estimated by piecewise linear polynomial function (PLPF) method. The simulation results show that the frequent and time domain characteristics are very proximal before and after excitation system aggregation. This proves the effectiveness and adaptability of the proposed method. ©2010 State Grid Electric Power Research Institute Press.


Zhang Y.,Tsinghua University | Wu W.,Tsinghua University | Zhang B.,Tsinghua University | Wan Y.,Jiangxi Electrical Power Dispatching and Communication Center | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

This paper presents an early warning and preventive control system for transient stability. This system has been used in several provincial power grids. Firstly, the framework and the main modules of the proposed system are introduced. Secondly, the key technologies of the system are also presented. An algorithm is implemented to calculate total transfer capacity (TTC) under four different power increasing strategies. The preventive control algorithm, which is based on transient energy function sensitivity, is also realized. Thirdly, some engineering-oriented methods are introduced to solve practical problems, which emerge in real application. There are several examples: a node-breaker model is implied to adapt to the changing operation mode, a scheme is presented to avoid misjudge of stability in the case of island, generation areas and load areas can be automatically divided with new method. © 2010 State Grid Electric Power Research Institute Press.


Huang X.,Henan Electrical Power Dispatching and Communication Center | Chai X.,Henan Electrical Power Dispatching and Communication Center
Advanced Materials Research | Year: 2012

The capacity of thermal power plants takes up 75 per cent of whole power generation capacity in China, and so a reserve of generation capacity margin that may adapt to the variations in power network load is of paramount importance. This paper proposes a concept: installed capacity margin, and basic mathematic modeling and example is analyzed. It would be supply theoretical help for real little thermal power plants shutdown schedules based on building detailed mathematical models after investigation of region-specific load structure characteristics and installed generator compositions. © (2012) Trans Tech Publications.


Huang X.,Henan Electrical Power Dispatching and Communication Center | Chai X.,Henan Electrical Power Dispatching and Communication Center
Lecture Notes in Electrical Engineering | Year: 2011

Power distribution network planning is an intricate combined optimization problem. The ant colony algorithm as a highly effective, random and heuristic global search technology can effectively solve large combined optimization problem. In this paper, special ant colony algorithm is presented to solve the obstacle bypass problem of network frame planning according to the characteristics of single stage power distribution network planning. The corresponding mathematical model is established, and the whole solution method is given out. The calculating result shows that this approach is feasible and effective. © 2011 Springer-Verlag.

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