Study On The Key Technology Of Synchronized Pahsor Measurement Unit

The study and application of wide-area measurement system (WAMS) which base on synchronized phasor measurement unit (PMU) is a foreland subject in power system, it is very important to improve the level of power system stability and security .As the basic unit of WAMS, PMU measure the phase parameters of power system can reveal the dynamic characteristics and provide a foundation for power system stability or collapse valuing or forecasting and control schemes. The aim of this paper is to study the key technologies of synchronized phasor measurement unit.First, the paper expatiates on the basic principle and development status in domestic and overseas of synchronized phasor measurement, also analyses the key technologies base on the study and application at the area.Considering one pulse per second (1PPS) of globe position system may be missed due to climate condition, fault, etc, the paper develops a high-quality backup clock for PMU according to the principle of Digital Phase-Locked Loop (DPLL) using Complex Programmable Logic Device (CPLD);When GPS signal is normal, the backup clock will tracking it, if 1PPS is missed the backup clock will supply a synchronous signal with error in limited range. The paper also analyzes the quality of backup clock and validates it by simulation and experiment.According to the require of PMU data synchronous, this paper analyses the applicability of some phasor estimation method which base on Discrete Fourier Transform (DFT) and proposes a new phasor estimation method which amends the sampling series to satisfied synchronous sampling. The simulation shows that the method has a notable accuracy improvement, and adds little calculation burden than traditional DFT. The favorable performance satisfies the accuracy and real-time of synchronized phasor measurements.Aim at the issue of data quality assessment of PMU, the paper proposesa new method which assess quality of phase data base on the difference between the input phase curve and estimation curve, it also offers a recursion arithmetic and simulation of examples.At last, the characteristics of PMU data and their communication framework are studied in this paper based on IEEE1344. The paper develops a Ethernet interface for PMU using Ethernet controller CS8900, and some function test have been done to the hardware circuit.