Power Quality In Photovoltaic Power Generation Detects And Analysis

As the photovoltaic power generation technology develops these years, and the Power Quality problem that caused from that Photovoltaic power generation system is vulnerable to external interference and the introduction of nonlinear components such as inverter is more and more obvious. On one hand of Power quality problems, the use of electrical equipment damage, on the other hand, there are harmful to the power system security and stability. It's vitally important to check the Power Quality Problem effectively and real-time for the running of power system.This paper mainly depends on the national quality inspection public welfare industry research special project, the project name: “Power quality in photovoltaic power generation detects and analysis".In this paper, we first study the domestic and international photovoltaic power quality detection methods to measure the device, and aiming to improve the existing detection algorithm and the lack of measurement devices. Out work focuses on harmonic detection algorithm, and analyzes the shortcomings of commonly used detection algorithms in the photovoltaic power generation system, then propose a sampling method based on quasi synchronous. At last, through the comparison from the simulation, this algorithm relative to the effect of the FFT algorithm, IEC clustering algorithm, the windowed interpolation FFT algorithm with a higher accuracy. As previous measuring device with measly function, and the accuracy is not enough. In this paper, the hardware circuit of measuring device using based on FPGA hardware circuit, and the AD, precision resistance components have a higher accuracy. In the part of software designing, we adopt MFC frame structure and make reasonable code optimization to accelerate the speed of the whole device and improve the precision of the device, finally realizing the graphical and digital real-time measuring device integratedAt last, we make a test to measure device by a standard source of harmonic and three-phase AC standard sources, the result of test shows that the fundamental error of irradiance is within 2%, the error of components is within 1%, the valid value of voltage meets within 5%, the deviation of the frequency and the voltage are also within 1%, the error of the harmonic voltage amplitude is about 4.45%, the error of harmonic containing rate is about 0.05%, the device satisfies the requirements of class I test instrument accuracy and project task accuracy standards, and compared with the previous detection device, the measurement device function in this paper is more perfect with a higher precision.