Research On The Methods Of Power Quality Data Storage And Comprehensive Evaluation

Because the sensitive equipment such as high-power power electronics device is widely used in the power grid,the power quality is affected in certain degree.With the development of electricity market,the collection,storage and evaluation of power quality data has become the main research direction in the field of power quality monitoring.Aiming at the problem of power quality monitoring,feasible schemes about collection,storage and evaluation of power quality data are proposed in this paper.First,the PQDIF format stipulated in the IEEE 1159.3/Draft9 standard is adopted to store of the power quality data to solve the compatibility problem.The operation mode of PQDIF file working in power quality monitoring system is analyzed,and then the physical structure and the logical structure of PQDIF file are summarized.Multiple conversion methods of PQDIF file are discussed,and the native support is chosen to generate the PQDIF file.The datasource record and the observation record of PQDIF is set to complete the conversion of PQDIF.Afterwards,the data recorded in the PQDIF file are allocated and processed,and the power quality evaluation index system is established based on the recorded data.The power quality evaluation method is studied.The respective characteristics of the subjective method and the objective method are analyzed.The principle of AHP(Analytic Hierarchy Process)is analyzed.The consistency of AHP matrix is improved and the subjective weight is calculated.The principle of Entropy Method is analyzed.The problem of unreasonable distribution of entropy weight is discussed.The fomula based on the optimal adjusting factor is proposed,and the objective weight is calculated.The target decision matrix is built by power quality data,and the comprehensive evaluation of power quality is enforced with the actual measurement data from the power grid.The evaluation result is analyzed to prove the evaluation method is effective.Finally,according to the data type recorded by PQDIF,the functional requirement and the accuracy requirement of power quality data collection terminals are analyzed.The platform based on OMAP-L138 is chosen for the design of the power quality data collection terminal.OMAP-L138 is the DSP/ARM chip with heterogeneous dual-core structure.AD7606 is chosen as the sampling chips.The hardware structure design of power quality data collection terminal is completed.The design of electric signal collection and calculation algorithm is completed.Based on the embedded Linux system the design of the graphical user interface is completed.The dual-core development components called SYSLINK is used to complete the information communication between ARM and DSP.The experiments is performed to validate that the device can complete the collection and storage of power quality data.