| Online monitoring technology for status of metering equipment is a new field of energy metering information application,which is based on metering information acquisition system in smart substation and combines data acquisition technology,IoT technology and AI technology.It is of great theoretical and application value to study the high-accuracy,highreal-time,high-reliability and high-safety technology of acquisition and monitoring under the new application situation.Energy metering of the power is based on transformers and meter meters with the transformer is the main equipment and its status is one of the key factors affecting energy metering.This paper proposes a solution that aiming at acquisition and monitoring of transformers operating status in smart substation.In this design,Synchronous data acquisition is implemented with protected voltage sampling,non-intrusive current sampling and high precision ADC,On-site monitoring of energy metering information is realized by a high-precision algorithm based on DSP,and the reliability and safety of the system are improved by other auxiliary technologies.This paper introduces the main contents and significance from four aspects: system and hardware design,research of algorithm,experimental verification and engineering application.First of all,aiming at the technical requirements of monitoring the secondary output of the 0.2-level accuracy transformer,the goal for high precision,high synchronous real-time,high security and high reliability is determined,The technical design that multi-channel real-time synchronization controlled by FPGA parallel logic control,precision sampling and information extraction based on FPGA & DSP & 24-bit AD,transformers metering information reliable reorganization controlled FPGA,transformers characteristic information local storage based on local database is designed.The scheme improves the overall performance of the system from the aspects of power supply reliability design,synchronous trigger time parameter matching,combined control circuit stability design,and accuracy design of analog signal transmission.Secondly,considering that the signal feature extraction algorithms are affected by errors due to both the spectral interference from the approximate rounding of data and the wideband noises,this paper analysis the relationship between the window function,the weighted interpolation method and the error of WMIpDFT algorithm.The key parameters of the noise suppression performance of the window function under the specific interpolation method are optimized.The spectrally-resolution adaptive improved double-weighted IpDFT algorithm with over 0.01% algorithm accuracy and better noise suppression performance is proposed.Algorithm execution efficiency optimization method when algorithm based on DSP and C++ is implemented.Thirdly,this paper tests the system performance of real-time accuracy,synchronization accuracy,and temperature cycling stability in the laboratory.The result displays that the realtime accuracy of the system voltage acquisition and monitoring system meets the accuracy of 0.05 level,the synchronization error is less than 50 ns,the phase dispersion of the longterm synchronous trigger is less than ±0.5?,and no abnormality occurs in the temperature cycle test for 5 days.Finally,in this paper,the developed system is used to collect and monitor the secondary output of 24 CVTs of a 220 kV booster station.The monitoring data conforms to the basic electrical laws of the transformer operation and proves the validity.The monitoring data is analyzed by the transformer online evaluation and early warning system.The result shows 4 CVTs may have error tolerances,which proves the significance and application value of the system developed in this paper. |
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