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The fundamental theory and control methods of Active Power Factor Correction (short for APFC) are introduced in this paper. It analyzes and studies the APFC based on the three-phase rectifier. In addition, the simulation model is built on the MATLAB and the results are shown in this paper. The results show that the grids-side input current wave is changed with a sine wave, has the same phase with...
Exploring a new method of line-tracking is the key to smart grid construction. Obtaining information of high-voltage transmission system by helicopter or unmanned aerial vehicles (UAV) will bring numerous images. The research of extra matter recognition of transmission system based on Hough Transform (HT) is performed in this paper. The gradient of gray image is used to detect the edge of transmission...
Construction of UHV power grid is the fundamental guarantee to the growing demands of electricity in the future. Six phase transmission lines can evidently improve power transmission density, and many countries pay attention to it. A new method of fault location and phase selection on six-phase transmission lines was analyzed in this paper. The six sequence variables method to analyze the electrical...
According to the theory of Voltage Source Converter (VSC) can control active power and reactive power simultaneously and independently, back-to-back VSC is applied to the synchronous parallel operation in power grids. Combined with the characteristic of UPFC circuit structure, this paper proposes a new scheme based on power transmission which can realize integrated functions of power system synchronization...
Studies on lightning discharge processes are foundation for well-know the lightning physics and effects, and it is very important to make optical, electric and magnetic observation data synchronized with each other. Combining with the China Grid Lightning Detection Network (CGLDN), this paper utilizes the latest high-speed CCD video system, Fast/Slow electric-field antenna, magnetic-field antenna,...
For the difficulties of catastrophic events assessment caused by complex uncertainties of network topology and electrical running state as well as their combination, a new method based on the dissections of network topology and electrical parameters is proposed. These two dissections can easily describe the inherent properties and variation of electrical parameters in the occurrence process of catastrophic...
This paper has summarized the history of the development of the state monitoring system of the power transformer and introduced the present situation in research, especially the multifold comparison on different methods to diagnose the trouble in transformer. This paper not only takes the comprehensive analysis on the extant online monitoring equipments, which is based on DGA, and methods of trouble...
When grid voltage is nonsinusoidal, the detection current based on the instantaneous reactive power theory has error. After analyzing the current detection error, a improved n current detection algorithm based on the instantaneous reactive power theory is proposed. The detection current is accurate by the improved current detection algorithm, and the complexity of the algorithm is no significant increase.
This paper addresses the problem of identifying the optimal location for power quality monitors.The proposed approach is based on using the integer programming-based model and PSO to solve the optimization problem. Establish a 0-1 sensitivity equation to form the constrains of integer programming by PSCAD/EMTDC.The proposed approach gives the minimum number of power quality monitors and their locations...
With the unceasingly development of the power system, the proportion of nonlinear loads is quickly increasing and harmonic sources become more and more. It has serious influence on the power quality. In order to protect the safe operation of power grids and safe use of electricity, various level power quality networks are gradually formed, which provides a sound basis for the analysis and application...
Aiming at regional power grid whose power supply is a substation that connects the upper and lower grid, REI (Radial Equivalent Independent) equivalent is applied to voltage and reactive power optimization control, and varying-intercept linear regression method is proposed to obtain equivalent parameters according to local data taking into account the difficulty of getting the upper grid operating...
The uncertainty of generation required to maintain system balancing has been growing significantly due to the penetration of renewable energy resources such as wind power and the impact of demand response. To deal with such uncertainty, RTO's require not only more accurate demand forecasting for longer-term prediction beyond real-time, but also demand forecasting with confidence intervals. In this...
As the output power of the photovoltaic (PV) cell changes with the insolation , PV cell temperature and cell voltage changing. It is necessary to control the operating point to draw the maximum power of the PV cell in order to increase system efficiency. In this paper, two-level single phase PV grid-connected system is designed, which mainly includes PV cell, BOOST circuit, inverter, filter and the...
Solid power system planning is fundamental to the safety, reliability and economy of power system operation. In the deregulated power grid environments, power grid planners not only have to handle massive geographic data, power equipment parameter data and grid operational data, but also have to solve very complex decision-making problems when they are committing power grid planning. Thus, it is necessary...
It is very important for the ±800kV UHVDC transmission project to study the overvoltage protection and insulation coordination of the converter stations because of its importance in the power grid. The paper studies the DC transient overvoltage of the converter station in the Nuozhadu-Guangdong ±800kV UHVDC transmission project by using the PSCAD simulation program. The simulation results show that...
Load model has great uncertainty characteristic due to the time-variation of load. As a consequent, it is essential to analyze the influence of load model on power system stability. The effect of load model structure and parameter on Yunnan power grid transient stability is researched in this paper. Simulation results indicate that load model has great influence on Yunnan power great transient stability...
The mechanism of Emergency DC Power Support (EDCPS) is analyzed based on a model in which two AC systems are connected by a HVDC Link. This model can be considered as an equivalent two-machine power system, and it is demonstrated that stepping up (or stepping down) DC power during the angle-swing-up (or angle-swing-back) course of the equivalent system can help absorb (or compensate) active power...
Under the concept of smart grid, a novel programming method is proposed in the paper for customer friendly distribution system considering the uncertainty properties of power quality. Due to the uncertainty of power quality during the change of power system structure, the assessment of potential cost caused by customers' equipment failures under possible disturbances for different planning schemes...
This paper presents a practical approach to implement the economic dispatch of the hydrothermal power system in Southern China. The proposed economic dispatch method first computes the initial generation plans for all generator units including hydro units, which are determined according to the equal incremental principal of hydrothermal system. The system loss is approximately considered during the...
A dynamic equivalent approach based on coherency is researched for dynamic simulation test in ±800 kV DC transmission project from Yunnan to Guangdong in China. To reduce the full system, the dynamic equivalent model of large-scale power system based on coherency is established, in which the identification of coherent generator groups, coherent buses reduction, aggregation coherent generator parameters...
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