Research on phase identification method of low-voltage distribution network users
Due to the unbalanced load in the distribution network,three-phase unbalance will occur.This paper proposes a user phase identification and three-phase current phase imbalance detection method.This method can effectively identify the phases of users in the same station area,and provide a data basis for electricity consumption information collection and station area management.Considering the dynamic characteristics of the power signal,firstly,the Taylor series is used to approximate the time-varying phasor of the signal.Secondly,the relationship equation corresponding to each data point in the window is simultaneously established,and the Taylor coefficient is solved by the least square method to obtain an accurate phase.Then,phase shift and phase compensation are performed on the phases at the user and the transformer,respectively.Finally,by comparing the relationship between the phase difference and the threshold value,the user phase attribution relationship is recognized.After the phase identification of the user,the phase difference of the three-phase current on the low-voltage side of the transformer can be used to judge the unbalance of the three-phase current phase of the distribution network,and provide monitoring and analysis data for the measures of commutation and network reconstruction when the three-phase unbalance of the distribution network occurs.The simulation results show that the method proposed in this paper can accurately identify the phase of users in the station area under the condition of frequency offset,and the identification success rate is higher than 90%under the condition of harmonic interference.Compared with the traditional user-transformer voltage correlation analysis method,the recognition accuracy and robustness of the proposed method have been greatly improved.
Taylor seriesphase identificationphasor measurementphase compensation
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