Design Of D-dot Voltage Sensor And Research On The Measuring System Of Three-phase Voltage

With the development of smart grid, the measurement of electric parameter plays an important role in electrical power system. For measuring voltage, the voltage transformers are analyzed and a new voltage probe is proposed based on the theory of electric field coupling. On the basis of studying single-phase D-dot sensor, two kinds of D-dot sensors are designed for actual measurement. The main work of this paper mainly embodies on the following aspects:① The principle of measurement for D-dot sensor is analyzed and the self-integral working condition is acquired based on the amplitude-frequency characteristic of D-dot sensor. For measuring the voltage of transmission conductor in the near-field and far-field, the double-pipe type and plate D-dot sensors are designed.② The equivalent circuit of double-pipe type D-dot sensor is analyzed for near-field measuring. The model that D-dot sensor measure the 110 k V overhead transmission line of horizontally arranged is built by Ansoft Maxwell. The system distribution parameters are acquired by Ansoft Maxwell. The optimization internal parameters of D-dot sensor are obtained through simulating the distribution parameters of frequency response.③ For far-field measuring, the charge simulation method is used to deduce the equations that solve the any point of synthetic electric field under the transmission line and the 220 k V overhead transmission line of horizontally arranged is built. The total electric field of plate D-dot sensor is decomposed on vertical direction. So the arithmetic of calculation the voltage is obtained and it is verified by Matlab.④ Three-phase voltage measurement system which includes terminal measurements and PC is designed based on study three-phase distribution parameter and decomposition synthetic electric field. Data and instruction communication is implemented between measurement hardware circuit and PC software program by using WIFI wireless network. The output signal of sensors is sampled and processed by system. The PC software program is developed by graphical programming software Lab VIEW. It implements the graphical display, analysis and saving for the waveform data sampled by measurement hardware circuit.⑤ The test platform is set up for probe steady state and transient respons test. For testing the measuring system, single-phase and three-phase simulation tests are done. The result shows that the sensor have a quick response with rapidly changing primary voltage and high accuracy of measurement. The probe measuring system can meet the goals of synchronization acquisition for multi-signals, signal without distortion.