Design And Optimization Of Standard Power Source For Digital Energy Metering Device Detection

Merging unit and digital meter are widely used equipment in digital substation.The accuracy and reliability of their measurement performance are the important guarantee for the steady and sustainable development of digital energy metering system,Standard power source is the core equipment for checking merging unit and digital meter,Ensuring its reliable performance and complete function is the premise of detecting merging unit and digital meter ComprehensivelyThe standard power source for the detection of digital energy metering devices can be divided into three-phase programmable power source and standard digital power source,The traditional three-phase programmable power source is difficult to meet the accuracy requirement when the output signal of traditional three-phase programmable power source is less than 5% of the secondary side of transformer,moreover,It doesn't have the real load function and the ability of Increasing the proportion of harmonics content and harmonic number is weak.This leads to the inability of some testing projects for analog input merging units.At present,there is no unified standard about digital power source.Many digital power source only have the function of outputting SV message,and it can not detect the abnormal communication state of digital meter according to standard,Because of this,it's difficult to meet the requirement of basic accuracy,In view of this,this paper refers to the relevant detection items in "Analog Input Combination Unit" and "Special Requirements for AC Measurement Equipment Part 3: Digital Energy Meter" Improving the traditional three-phase programmable power source and standard digital power source from two aspects,algorithm and hardware design.1.In the arithmetic design,An improved DDS arithmetic is proposed to solve the problem of system error caused by phase truncation in traditional DDS principle.An improved "PIDT" control arithmetic is proposed to solve the problems existing in traditional PID control arithmetic,such as temperature,cumulative gross error and slow convergence speed.In addition,To ensure that the standard digital power source can effectively simulate communication anomalies,two random sequence generation algorithms are designed switched by serial commands to guarantee the output anoma messages randomly.2.In the hardware design,The signal generation circuits and feedback circuits of the three-phase programmable power source are optimized,The high-quality power amplifier is used to replace the traditional current elevator and the ring voltage transformer to ensure that the three-phase programmable power source can output arbitrary waveforms.Replacing the traditional electrical to optical chip with the optical ethernet Chip DP83848,at the same time Configure the output interface to RMII type to reduce the time deviation of SV message dispersionTest results show that the output accuracy of the three-phase programmable power source can reach 0.05 level,the real load function is normal,the secondary side of the transformer can be dynamically reproduced though this function,The output interval of standard digital power source is controllable,It's dispersion is not more than 20 ns,the autocorrelation of abnormal sequence is low and the probability is controllable,In summary,The designed standard power source meets the requirements of merging unit and digital meter detection project...