Studies On Some Key Problems Of Wide Area Measurement System Oriented To Distribution Network And The System Development

The synchronized phasor Information measured by wide area measurement system has a wider range of applications than traditional asynchronous information, but now the wide area measurement system is only used in the Part of the transmission grid and basically has not been applied in the distribution network.This paper analyzed the structure and function of existing wide area measurement system, solved the problem of the grid fixed network monitoring, researched a flexible wide area measurement system, then used it on some applications to make the GPS-based power synchronous acquisition method in a wider range of the power system. The main contents included the following aspects.1. The overall scheme of flexible wide area measurement system oriented to distribution network was designed. Using this system, we can layout several temporary survey points in local power grid more flexible, it not only makes up the monitoring system, but also can collect the synchronous measurement information. Through analyzing the measured data, the problem can be solved. Then, flexible wide area measurement system can recovery in order to apply to the other networks. So using the limited equipment can realize the accurate comprehensive coverage for power network and expand the application range of the wide-area measurement system.2. A triple-spectrum-line windowed interpolation FFT algorithm was proposed. Under the conditions of a truncated of the discrete sampling data non-integral period,the amplitude and phase of the signal can be accurately obtained using this algorithm. The simulation results have verified that the algorithm has a better precision than the double-spectrum-line interpolation algorithm using the same window. Thus the effectiveness and practicability of the algorithm have been verified.3. Some problems of harmonic state estimation using flexible wide area measurement system was studied, including optimal PMU placement and harmonic state estimation algorithm. This paper analysised shumed frog leaping algorithm and greedy algorithm, and applied them to solve the problem of optimal phasor measurement units placement. The algorithm presented by this paper improves convergence speed and global search effect when comparing to niche genetic algorithm, particle swarm optimization and other algorithms mentioned in the paper. A harmonic state estimation method based on weighted total least squares and IGG robust least squares estimation was proposed. In this way, state estimation algorithm can have a stronger capacity of resisting gross errors. Simulation results verified the effectiveness of the method.4. Some problems associated with the parameters online measurement of the transmission line and transformer was studied. A parameters online measurement method was proposed and the method used multiple sets of multi-load periods data of the tested model to building high redundancy equations. In order to solve the equations, an algorithm combining of the k-means clustering analysis and IGG robust least squares estimation was proposed. The simulation results have verified that the algorithm is effective in the case of considering Harmonic, grid frequency fluctuations, measurement noise, sampling synchronization error and gross error.5. The flexible wide area measurement oriented to distribution network was developed and was used for harmonic synchronous monitoring, transmission line and transformer parameter online measurement. The experimental results have demonstrated that the developed system is practical and theoretical methods are correct.