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Deng J.,Provincial Level Key Laboratory of Smart Grid | Deng J.,University of Sichuan | Liu J.,Provincial Level Key Laboratory of Smart Grid | Liu J.,University of Sichuan | And 3 more authors.
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2011

As the traditional under-voltage load shedding based on static load index may cause the inaccurate analysis, a dynamic voltage stability margin index based on local real-time measurements is derived, which considers the characteristics of node load and reflects, in an approximately linear way without Thevenin equivalence, the load margin of voltage-varying area to greatly reduce the dimension of optimization calculation. The mathematical model of centralized optimal load shedding is built based on that index and HSPPSO is introduced to solve the problem. The simulative results for IEEE 39-bus system show its better adaptability.


Sima W.-X.,Chongqing University | Fang X.,Chongqing University | Yang Q.,Chongqing University | Yuan M.-Y.,Nanchong Electrical Power Bureau | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2010

In order to mitigate the serious corona discharges in Nanchong 500 kV substation, we established a simulation model by the COMSOL Multiphysics software based on FEM to investigate the corona in the area, and believed that the serious discharge was caused from the facts that complex electrical wiring, wire arrangement and other factors were not taken into account when selecting shielding rings and the superposition of electric field generated by conductors around the door-type tower. Many countermeasures, such as to optimize geometric parameters of shield rings, to adjust the connection mode, and to change the phase sequence, were used to eliminate the serious corona discharges. It is revealed that optimizing geometric parameters of shield rings, and adjusting connection mode or changing phase sequence need to change the existing electric connection, which is hard to apply, but it can be used as reference for future project design. Corona is a common discharge phenomenon in high-voltage power transmission and transformation equipment, the high frequency pulse current generated by corona not only causes power loss and interference with radio communication, but also produces ozone and nitrogen oxides. In order to mitigate the serious corona discharges in Nanchong 500 kV substation, the paper establishes a simulation model in COMSOL Multiphysics software based on FEM and investigates the corona in the area, and gets the conclusion that complex electrical wiring, wire arrangement and other factors were not taken into account when selecting shielding rings and the superposition of electric field generated by conductors around the door-type tower result in the serious discharge. Many measures, such as to optimize geometric parameters of shield rings, to adjust the connection mode and to change the phase sequence, were used to eliminate the serious corona discharges. It is efficient with the method that optimizing geometric parameters of shield rings, and adjusting connection mode or changing phase sequence need to change the existing electric connection, which is hard to apply, but it can be used as reference for future project design.


Wang Y.,Sichuan University | Yang D.,Sichuan University | Liu Y.,Sichuan University | Chen C.,Nanchong Electrical Power Bureau
Applied Mechanics and Materials | Year: 2013

Considering the multi-valued mapping relationship of equipment response event to voltage sag, a lattice ordered evaluation method is proposed in this study. Each possible resulting state of equipment response event is described by an interval number. The interval numbers is with the characteristics of lattice order presented by the upper and lower probabilities. The possibility degree matrix is introduced to compare resulting states without satisfying the axioms of connectedness. Personal computer is simulated and compared testing results. The results have shown the validity and feasibility. © (2013) Trans Tech Publications, Switzerland.


Ding L.,Nanchong Electrical Power Bureau | Ou Z.,Nanchong Electrical Power Bureau | Tang Z.,Nanchong Electrical Power Bureau | Liu G.,Nanchong Electrical Power Bureau | Zeng B.,North China Electrical Power University
Dianwang Jishu/Power System Technology | Year: 2013

Parameters of transmission lines are the basis of computations and simulations of power system. Based on the synchronized phasor measurement-based data mining, the impacts of identification model, shunt reactor and measurement error on line parameter identification are analyzed. Analysis on identification model shows that the -shaped equivalent model can be applied to the computation of distributed parameter identification model and lumped parameter identification model, and the influence of line length on unit length line parameters can be determined by sensitivity analysis. The respective incidences of shunt reactor position and compensation degree on the identification of resistance, reactance and capacitance are researched. Analysis on small perturbation caused by measurement error reveals the impacting mechanism of amplitudes and phase angles of voltage and current on parameter identification results, and the impact of shunt reactor on indentified capacitance and the impact of measurement error on identification results are confirmed by simulation example.

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