Hui Qian

Research on Voltage Stability of Photovoltaic PCC Based on the Hopf Bifurcation Theory

Due to the large number of distributed generation and nonlinear components in the Photovoltaic (PV) System, Voltage condition at the point of common coupling (PCC) faces severe challenges. Evaluation of the PCC voltage stability has become critical to the steady operation of the PV system. PV system is a typical nonlinear nonautonomous system, and bifurcation theory, as one the effective ways to solve the nonlinear dynamic system, was adopted to conduct a research on voltage stability or collapse on the PCC. In the paper, a PV system equivalent circuit model was proposed. In order to find the main parameters that contribute most to the voltage instability on the PCC, a mathematical analysis was conducted based on the equivalent circuit. Then, with irradiance intensity chosen as the bifurcation parameter, the Hopf bifurcation simulation was conducted. A MATLAB m-file was developed to study the voltage stability analysis. A MATCONT bifurcation software has been used to conduct the bifurcation analysis.

Modeling and Simulation of Electromagnetic Transients for Photovoltaic Power Generation Systems

With the increase of the number of photovoltaic grid connected power plants and the increase of capacity, the impact on the protection and control of the grid can not be ignored. The establishment of electromagnetic transient simulation and equivalent calculation model of photovoltaic power station is the basis for studying its grid connection characteristics and its impact on relay protection. The common form of grid connected photovoltaic power station, built by a single-stage inverter grid connected photovoltaic power generation unit model, and the use of photovoltaic power system electromagnetic transient simulation model built in PSCAD/EMTDC to verify its validity in steady and transient conditions. On this basis, an equivalent calculation model of photovoltaic power plant composed of photovoltaic units is presented, and its effectiveness is verified by simulation.

Research on Modeling of Integrated Information System for Photovoltaic Power Plant

In order to ensure the stable operation of the power grid, this paper aims at the modeling of the integrated information system of the photovoltaic power plant, and the model of the PV module is divided into physical characteristics. In order to ensure the stability of the power grid, Model and external characteristic model. The PV module model based on the physical characteristics is based on the mathematical model. The PV module model based on the physical characteristics can accurately reflect the physical characteristics of PV modules, the high simulation precision and the PV module model structure based on external characteristics Simple, and parameters corresponding to the PV module product parameters, although the accuracy is not based on the physical characteristics of the PV module model of high precision, but the error is small, to meet the practical application of the project.

Minimization of the DC Component in Three-Phase Transformerless Grid-Connected PV Systems

At present, the research on the quality of micro-grid power at home and abroad is still at the initial stage, which focuses on the study of the power quality characteristics of micro-sources. There is little research on the quality control of micro-grid power and the power quality adjustment device for microgrid. In particular, there is no literature on the power quality of the microgrids containing the power quality regulator, and there is no in-depth study of the power quality during its operation. In this aspect of the research and exploration process, this paper summarizes the special problems of multi-inverter microgrid and micro-grid distribution network power quality.

Research on Homogenization Modeling and Planning Method of Thermoelectric Combined System

At present, the energy situation is more and more serious, improve the efficiency of energy use, improve the energy structure, adhere to sustainable development has become the primary topic of social development. Cogeneration is a cascade of energy use, with significant energy-saving potential, and gradually become a regional heating system, one of the main forms of heat. In this paper, the homogenization modeling and planning method of cogeneration heating system is systematically summarized and analyzed technically.

Photovoltaic Power Station Integrated Information System Modeling and Reliability Evaluation Method Research

Along with our country the implementation of the strategy of developing the new energy, solar energy is a kind of ideal clean energy future energy, with the power grid operation requirements of photovoltaic power generation system is increasing day by day, for the needs of the operation and control, is necessary for photovoltaic system monitoring, photovoltaic power plant key components of condition monitoring information system integration, standardization, information network optimization, system reliability evaluation technology, internal information interaction of photovoltaic power station, coordinated operation of photovoltaic power station cluster has important significance. The IEC 61850 standard is the most perfect substation automation communication standards, powerful, with wide applicability, various devices can be implemented by following the standard interoperability, so as to achieve the sharing of information.

Technology of Weak Node Identification of Grid-Connected Photovoltaic and Energy Storage System

The effect of stability on reliability is a complicated problem of power system operation, and this issue has not yet been paid enough attention to the relevant research. Aiming at the problem of weak node based on voltage stability, This paper presents a method to evaluate the reliability and the weak points of optical storage and grid connected system from the angle of node voltage. Proposed the two identification of Minimum Voltage and Bus Voltage Change of the power system is the most weak node voltage indicators. This paper proposes node two description of voltage drop expectation and node voltage expectation of load node and system reliability of node voltage expectation index. And the probability of the weakest node is selected and sorted, and this can provide the risk information for the system operators to provide the uncertainty of load growth. The validity and consistency of the proposed method are verified by the analysis of the IEEE30 node system which is added to the photovoltaic energy storage unit.

The Control Method and Design of Photovoltaic Tracking System

The solar energy has an enormous developing application capacity as one kind of green renewable energy source which can be continuously used forever. But there is tremendous relationship between photovoltaic cells output characteristics and the change of external environmental factors, currently the efficiency of PV cells is not only low but also expensive on a large scale of production. It is very important to further improve the efficiency of its device. This is an important question which has need to be solved at present. In this paper, the feed-forward and closed-loop control trackinging scheme is proposed to improve the tracking efficiency of solar photovoltaic panel. The solar photovoltaic panel rotation angle for the feed-forward track is obtained according to the trajectory of the sun. The photoelectric sensor is used to detect the photoelectric signal for the closed-loop control of solar photovoltaic panel, so that the errors of the tracking devices of solar photovoltaic panel are overcome during the installing, production and processing and the tracking control accuracy is improved greatly. In addition, solar radiation utilization rate is improved exactly through the simulation experiment.