Development Of High Accuracy GPS Synchronous AC Signal Source

Increasingly complicated modern power system structure, timely and accuratelyjudge the power system anomalies and predict its trends and take some controlmeasures to avoid the accident, it has been the main part of the power system controlareas. Synchronous phasor measurement unit (PMU) as part of the Wide AreaMeasurement System, has been widely used in power system dynamic monitoring,state estimation, system protection, regional stability control, system analysis andforecasting, etc. PMU before and after the network must have their validated on aregular basis to ensure that static and dynamic performance of PMU meet networkrequirements to protect the power grid stability, security operation. This topic researchof GPS synchronous AC source is part the calibration device of PMU. The calibrationdevice of PMU is constituted with power amplifier module, data acquisition unit,background data processing centers and GPS synchronous AC source together. Itcould satisfy both the PMU static and dynamic performance testing.This topic adopts double DSP architecture and the system is divided into twoparts of the communication&control module and the signal generator module.Communication&control module is done by the Ethernet controller of ENC28J60fordata exchange with the host computer and receive control instructions from the hostcomputer. The Serial Communication Interface is completed to receive and resolvethe GPS message. And the double port RAM is completed to communication betweenwith the double DSP. Signal generation module exploits the computing power of theDSP high speed to realize the DDS arithmetic and output required signals. The signaltransit DAC8820of the16bit high speed D/A converter and high speed signalconditioning circuit. Processing the1PPS external interruption had been used forsynchronous output with GPS second pulse.This article attempts to elaborate on the theoretical analysis, whole schemedesign, hardware circuit selection and software programming. Firstly, it put forwardthe objective and significance of developing GPS synchronous AC source. Byanalyzing the current research status at home and abroad, it put forward the functionof the realization of the device and to achieve the performance indicators. According to the function and performance index, it present total design scheme and analyzed theerror of source of GPS synchronous clock and analyzed the error of GPS synchronousclock and the principle of DDS algorithm and its error. Then this text detailedintroduced the design scheme of hardware structure and the realization process ofsoftware programming. And lastly, this article recommends the emerging issues andsolutions when the hardware circuit and the software program are commissioningprogress. At the same time, the experimental data and the experimental results arerecorded in detailed. The experimental results show that: the functions which we needhave been implemented. Comprehensive error of the system output reached amagnitude of0.05. And this device had been calibrated by National Institute ofMetrology.