Time filter

Source Type

Huang Y.,University of Sichuan | Huang Y.,Smart Grid Key Laboratory of Sichuan Province | Liu J.,University of Sichuan | Liu J.,Smart Grid Key Laboratory of Sichuan Province | And 4 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

A battery model is developed. The scale effect of electric vehicle centralization is analyzed and a framework of centralized electric vehicles taking part in vehicle to grid is described. By developing the load frequency control model for electric vehicles participation, the role and effect of the control model is studied. The simulation results show that, as a type of mobile battery energy storage facility, electric vehicles can provide faster system reserve by effective controlling. © 2012 State Grid Electric Power Research Institute Press.


Zhang L.-Y.,Sichuan University | Xiao X.-Y.,Sichuan University | Ma C.,Sichuan University | Feng G.,Zigong Electrical Power Bureau | Pu S.-W.,Sichuan Electric Power Corporation
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2013

Tree-related failure caused by large-scale power flow transferring is one of the most important causes of power grid catastrophic accident. Predicting the flashover time and probability after the later tripping is an important subject to prevent system blackouts. Considering dominant vegetation growth, circumstance and power flow transferring, quantitative depicting method for the influencing factors and prediction method of line fault probability and time are proposed. Combining the randomness of influencing factors and power flow, an approximate linearization method is used to determine line heat time factor. With the help of probability density function of line contacting tree, line contacting tree time and probability is predicted. Two cases simulation results show that the contacting time and probability mainly depend on line final steady state power and circumstance factors. When the line power flow is changing tempestuously, the proposed method can predict the tree-related fault time and probability in time. These results can provide reasonable decision-making for power system operators to prevent power system blackout.


Zhang Z.,Chongqing University | Wang K.,Chongqing University | Tang J.,Chongqing University | Zhou J.,Zigong Electrical Power Bureau | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

Regular methods for detecting partial discharge of transformers include the pulse electric current, the dissolved gas analysis (DGA), the ultrasound, the radio interference voltage (RIV), the light detection, the radio frequency, the chemical method, etc. According to the principle of the above methods and the characteristic of ultraviolet ray of corona discharge, a new detection method for discharge of transformers based on ultraviolet pulse detection is proposed. The relationship between corona discharge and ultraviolet ray, as well as the spreading characteristic of ultraviolet ray inside transformers, are analyzed. The detection principle of ultraviolet pulse detection is expounded. A monitoring method to positioning corona discharge inside transformers is put forward. The method of ultraviolet pulse detection is designed and validated by experiments. The results demonstrate that this method can be applied to online monitoring for corona discharge of transformers. ©2010 State Grid Electric Power Research Institute Press.


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.


Sima W.-X.,Chongqing University | Deng J.-Z.,Chongqing University | Lu M.,Henan Electric Power Research Institute | Yang Q.,Chongqing University | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2010

In order to improve the electric field and potential distribution, taking the combined use of composite insulators and glass insulators as an example, we put forward a new method to improve the electric field distribution of composite insulators, established a three-dimensional electric field calculation model of composite insulators in the transmission line, and studied the improved situation of surface potential and electric field distribution of composite insulators with glass insulators installed in the high voltage side of composite insulators at different levels of voltage. The results show that by this means, the voltage that the conducting wire side of composite insulators can withstand is lowered; distorted electric field is eliminated; the electric field distribution in the ends of composite insulators is improved. Finally, we recommend the number of glass insulators which should be installed in the high voltage side of composite insulators at different levels. According to the test results of 110 kV composite insulator carried in the artificial fog chamber, the result shows that the flashover voltage is obviously improved and the voltage gradient is slightly changed after series connection glass insulator, because the pressure effect of glass insulator and the flashover arcing are inhibited certainly.


Li J.-X.,Zigong Electrical Power Bureau | Feng G.,Zigong Electrical Power Bureau | Fan K.-L.,Zigong Electrical Power Bureau | Chen K.,Zigong Electrical Power Bureau | And 2 more authors.
2011 International Conference on Electrical and Control Engineering, ICECE 2011 - Proceedings | Year: 2011

The article focusing on the situation of transmission network operation and maintenance introduces a monitoring and controlling management system for transmission network operation and maintenance. This paper says its principle, structure, software function and application. The whole system containing circuit monitoring device, maintenance monitoring device and the background management system uses GPRS and GPS to monitor operation and maintenance, and locate faults. Manager can inquire line operation and maintenance through the backend system. By practical application, the results show the system works reliability. © 2011 IEEE.


Zhang Z.-L.,Chongqing University | Peng M.-J.,Chongqing University | Li D.-W.,Chongqing University | Zhou J.,Zigong Electrical Power Bureau | And 2 more authors.
Chongqing Daxue Xuebao/Journal of Chongqing University | Year: 2012

In order to improve the computational efficiency of the insulator electric field inverse problem, the fast multi-pole method has been introduced to the traditional simulation charge method. Tikhonov regularization is used to process the ill-posed characteristic of inverse problem solution caused by the interference. Newton method is used to search the optimum solution, and then the actual field source parameters of insulators and the practical voltage distribution on the surface of the insulators can be obtained. The fast optimization algorithm has been verified in point charge model. And 110 kV insulator string is carried out to demonstrate that the fast optimization algorithm is much faster and more efficient than traditional method.


Chen W.,Chongqing University | Chen X.,Chongqing University | Tang J.,Zigong Electrical Power Bureau
2010 International Conference on High Voltage Engineering and Application, ICHVE 2010 | Year: 2010

Oil-paper insulation system is the most common insulation method of high-voltage apparatus. As the event of air-gap discharge can lead to aging and disruption of the insulation system, awareness of emergence and development of air-gap discharge in time could be helpful in finding internal latent fault of oil-paper insulation system. The paper does research on the air-gap discharge in the oil-paper insulation, and uses kernel principal component analysis method to reduce the dimension of statistical parameters and to extract new characteristic parameters. The sample signals at different times during the development process of discharge are adopted to cluster the new characteristic parameters. The air-gap discharge development process can be divided into four stages according to the information generated at different periods of the process combined with the clustering results. The four stages can be defined as: incipient discharge, developing discharge, constant discharge, pre-breakdown. ©2010 IEEE.


Zhang W.,University of Sichuan | Xiao X.,University of Sichuan | Fan K.,Zigong Electrical Power Bureau
Sichuan Daxue Xuebao (Gongcheng Kexue Ban)/Journal of Sichuan University (Engineering Science Edition) | Year: 2014

Based on the voltage variations, a new approach called 'lower threshold value, more criterions' was proposed to enhance the single-line-to-ground fault detection sensitivity in neutral un-effective gounded system. The zero sequence voltage, fault phase voltage and un-fault phase voltages would change simultaneously when the single-line-to-ground fault happened in the system. The variations of the voltages were in different fixed intervals considering the effect of fault impedance and fault distance. Then the fault detection method based on the several voltage variations was proposed. The algorithm based on many voltage variations avoids being affected by normal operations of system and the small features of fault, and the sensitivity of the fault detection was enhanced by lower threshold. It could be used for the high impedance fault detection. The enhancement of anti-interference and anti-fault-resistance of the algorithm was proved by the large numbers of simulations using PSCAD/EMTDC program. The method is beneficial to the accurate and reliable single-line-to-ground fault detection.

Loading Zigong Electrical Power Bureau collaborators
Loading Zigong Electrical Power Bureau collaborators