Study And Design Of Power Supply Ofdistribution Network Fault Indicator

With the development of the strong smart grid,the Power System is developing with the direction of high voltage and large capacity.It is especially important to ensure the safety,stability,and reliable operation of the Power System.Therefore,it is of great significance to monitor and control the transmission line in real time and reflect the running status of power equipment in time.The monitoring equipment in real time on-line works in the wild and covers a wide area,which makes monitoring equipment more and more demanding on the performance of the power supply.Solving the power supply problem of monitoring equipment is becoming an important factor in its technological development gradually.In this paper,a low-cost,maintenance-free and long-term power supply reliable CT switching power supply is designed for the distribution network fault indicator R1 earch using a combination of theory,simulation and experiment.The main work is as follows:Firstly,a simplified circuit model of the power-acquiring CT is established,and then the current flowing into the rectifying and filtering circuit is calculated according to the characteristics of the square wave of the voltage waveform at the secondary side of the current transformer,and the mathematical relationship with the load voltage and load R1 istance,excitation reactance and primary current are further deduced.By maximizing the load voltage and output power when defining the start-up current,the parameters of the power-acquiring CT are determined.The power-acquiring circuit of CT is simulated and verified by actual experiments.The results show that the theoretical calculation R1 ults are in agreement with the experimental results,which verifies the correctness of the theoretical calculation.Secondly,the rear circuit of power-acquiring CT is designed,through the R1 earch and design of lightning protection circuit,SCR overvoltage protection circuit,rectifier leakage circuit and anti-R1 tart circuit and so on,completed the overall design of the rear stage circuit and made out the physical map of the rear circuit.Finally,a prototype of CT power supply is made based on the above studies and an experimental platform is built.Through the test items about start current test,low current protection circuit operation test and load voltage test,medium current protection circuit operation test and load voltage test and high-current protection circuit operation test and load voltage test and so on,the results show that the designed power supply can meet the wide current operating range.It provides a complete power supply solution for cable line monitoring equipment,which has important engineering practical value and lays a certain foundation for solving the long-term stable and reliable power supply technology required for monitoring equipment.