Research Of Development And Application Of Phasor Measurement Device For Distribution Network

In recent years,the structure of the power distribution network present the complicated characteristics.Measuring equipment which have been installed have been unable to meet the needs of the measurement,such as Feeder Terminal Unit(FTU) and Remote Terminal Unit(RTU).The PMU provides real-time synchronization data of all installed nodes, which make operating personnel master the state of the entire network in time. In addition, we also can monitor the fault condition of the entire network through the fault location algorithm with the data provided by PMU, which lays a solid foundation for the stable and efficient operation of the distribution network.Based on the full understanding of the hardware and software architecture of the PMU and its work principle, in combination with the characteristics of the power distribution network, Distributed Phasor Measurement Unit, which has higher cost performance and is suitable for fault location, is researched and developed.The system architecture of DPMU is designed and the whole device is divided into several modules including the processor module,the communication module,the clock module, the analog and digital module with the chip selected,the circuit designed and the performance verified.Commonly used the phasor measurement algorithms in practice also are studied. To solve the problem that operation frequency of power grid is not fixed, a novel synchronous phasor measurement method is proposed, in which the real-time operation frequency of power grid is obtained through the software and hardware, the synchronous sampling frequency is calculated through the software and eventually the accurate phasor of the voltage and the current are calculated by Fourier. According to the requirements of《Technology Guidance of Power System Real Time Dynamic Monitoring System》, the amplitude and phase angle of DPMU is tested and the result is precise.Except that,the related researches of fault location in domestic and foreign are researched, especially for the study of the algorithm of faulty line selection and fault location based on single-phase grounded transmission line in small current neutral grounded system.To obtain accurate information of fault location in a short time after fault,fault location system with DPMU has been set up, which reduce the data delay time and make full use of the hardware and software performances of the installed node, so as to improve the speed of fault location. According to the actual situation of the distribution network, the building process and working process of fault location system have been designed. For the changes of power network topology, nodes change process,which is suitable for the real-time synchronous changes of the topology of fault location system, is presented, which improves the flexibility of application of fault location system.For the fault location system, a more accurate algorithm with regard to faulty line selection and fault location has been adopted to adapt to small current neutral grounded system.The algorithm uses the double side synchronous data, which can not only eliminate the influence of different neutral grounded way and transition resistance,but also improve the accuracy of location.Finally,based on the above work, set up the single-phase grounding fault simulation model of 10 kV neutral resonant-grounded system by Matlab/Simulink, Write the software algorithm of fault location and verify the accuracy of the algorithm.The simulation results show that the results of the fault line selection and fault location are precise by the synchronous data on both ends.