Development Of A Low-cost And Small-Scale Distribution Network Wide-area Monitoring Device

To ensure reliable and safe operation of the power grid,wide-area monitoring and controlling technology plays an important role.At present,wide area monitoring system(WAMS)based on phase measurement unit(PMU)has been applied maturely in the main network.As the distribution network lines large,wide and long of realistic features,wide-area monitoring device of main network which is full-featured,large-sized and expensive has not been applied maturely.In the field of distribution network,miniaturization,low cost and easy to install are development directions of wide-area monitoring device.However,in order to meet the demand for a low-cost miniaturization apparatus,it is incompatible with the realization of the function complexity and the measurement precision.Taking the field application into account,wide-area monitoring devices will also be affected by harsh environmental impact,as well as the limitations of maintaining because of human existence.This paper presents a low-cost,small-scale distribution network widearea monitoring device,which mainly consists of power supply module,voltage sensing module,current sensing module and main control communication module.First,in this paper,a two-half-ring differential winding PCB Rogowski coil is designed as a current sensor,and its working principle and the influence of interference factors are analyzed,of which the measurement accuracy and anti-jamming performance are also verified by experiments.Then,based on the distributed capacitance of the conductor to the ground and the sensor and the wire,a voltage measurement model and a voltage sensor are designed,of which the influence of actual engineering factors on the measurement results are also analyzed and validated.After that,the automatic calibration technology of voltage sensor is studied according to the principle of capacitance division and measurement model,and a self-calibration method for phase voltage measurement of three-phase transmission line is designed.The known parameters are superimposed on the unknown parameters by series switched capacitor,and PSO particle swarm algorithm is used to solve the nonlinear equations to achieve automatic calibration.In addition,the field application technology of the wide area monitoring device is also studied in this paper.The distribution of the electric field of the distribution network is analyzed by Comsol Mutiphysics software,which can provide the reference for the installation of the wide area monitoring device.Finally,the whole device was tested for tower impact and field installation.At present,the test prototype developed in this paper has been on-line operation,the device module can be stable and normally work,and measurement results can reflect the line voltage and current accurately.This design can meet the requirements of low cost,miniaturization and easy installation.It provides a new solution for the development of the wide area monitoring device of distribution network,and has broad application prospects.