Study On Phase Measurement In Power System

With the high speed development of Information and Computer Technology,Digital Signal Process technology has been a key science more and more. DSP,this kind of chip having a special architecture helps us to process some digitalsignals into realization. Phase measurement has important significance in thepower system.This paper designs the circuit of data acquisition and signalprocessing by using the DSP chip as core. The circuit is applied in the phasemeasurement of the power system.The purpose of subject is to achieve the phase difference measurement ofthe power system. Based on the further analysis about all kinds of phasemeasurement system, the research of phase measurement system is made in thepaper. According to the work flow, the entire system can be divided into severalblocks: signal adjust model, data acquisition and management model, Theseunits can be subdivided single function parts, which are designed and testedrespectively. this paper realizes voltage signal range automatic switch by theprinciple of replicable-triggered monostable multivibrator based oncharacteristic of power system and give the simulate result. Phase measurementresearch and realization adapt TMS320VC5410 as core process unit based onthe principle of fast fourior transform. The input signals pass through theprepositive circuit which transforming the measured signals (voltage or current)into small voltage signal, and then pass low filter to wipe off noise. Because ofthe instability, frequency of power system, so the system adopt PLL circuit tocontrol A/D logic sampling to turn the synchronize sampling into realization.Analogy signal can be transform to digital signal by ADS7864, process FIR andFFT operation in DSP, and then can measure the phase.This paper provides FFT phase-detecting algorithm based on DSP canmeasure the phase exactly and give the measure result and debug process.