Research On Motor Actuator And Control Method Used In GIS Disconnector

With the continuous development of China’s smart grid, "smart high voltage switchgear" has become the advantage selection in the large-scale construction of power grid. To improve the intelligent level and reliability of disconnector operations in gas insulated switchgear (GIS), the influence of the operating speed of disconnector on the re-strike process between contacts and very fast transient overvoltage (VFTO) characteristic are analyzed in this dissertation by theoretical analysis and experimental data, the research idea of suppressing VFTO by disconnector is proposed. According to controlled requirement of operating speed of disconnector, the limited angle permanent magnet motor (LAPMM) and control method used in 550kV GIS disconnector are proposed. The operating characteristic experiments of disconnector are carried out, the re-strike process between contacts and VFTO characteristic in adjust-speed operation is analysied which lay foundations of theory and practice for suppressing VFTO by disconnector in future. The author works on areas such as VFTO calculation, development of the driving motor and control system, operating characteristic experiment of disconnector. The main research work is as follows:(1) The theory of multiple re-strike in closing and open operation of GIS disconnector is researched, mathematical model of dynamic arc of contact gap is established. According to the arrangement of experimental base of VFTO test loop in Wu Han, VFTO simulation model of multiple re-strike of disconnector contact gap is established, and the simulation method of variable time-step in re-strike process is presented. The related data in the process of re-strike and VFTO of disconnector power side and load side in the opening and closing operation are got. The influence of disconnector operating speed on VFTO amplitude characteristic, re-strike times, and duration of re-strike process is researched. The probability distribution of short bus residual voltage and maximum VFTO under different operating speeds of disconnector are analyzed statistically, characteristic relation of operation speed and VFTO characteristics are determined. The accuracy and applicability of the simulation model and calculation method has been validated by comparative analysis with the existing VFTO experimental data.(2) The ZF27-550 GIS disconnector is used as object of study, the multi-body dynamic mathematical model of disconnector with motor actuator is established, and the mathematical relation between contact stroke and rotary angle of LAPMM are obtained. The load torque and equivalent moment of LAPMM shaft is reduced by calculation method. The comprehensive design of LAPMM by theoretical analysis of main structure parameters and simulation calculation of dynamic performance are carried out, the theoretical design basis of stator and rotor structures are presented. The mathematical model of LAPMM is established, magnetic saturation effect of air gap and stator teeth of LAPMM are researched, the influence of different structure parameters on dynamic characteristics of LAPMM are analyzed. Suppression method of torque fluctuation in the LAPMM winding commutation process and commutation method which is based on winding current are studied, the overall design scheme of LAPMM is determined, and the prototype is carried out.(3) The motive controllability of motor actuator used in disconnector is researched, and the mathematical relation between speed of LAPMM and operating voltage is established. The PID based on RBF neural network is proposed, and identifier and iterative algorithm of parameter are designed. The calculation model of RBF-PID is established, the tracking performance and anti-disturbance performance of LAPMM are analyzed under PID and RBF-PID contrastively. According to theory of LAPMM and requirement of control method, the scheme of control device that take DSP as the computed core is established, the communication protocol of upper monitor and control main program are developed.(4) According to coordination characteristic between 550kV GIS disconnector and motor actuator, the scheme of mechanical connect between transmission device of disconnector and shaft of LAPMM is designed, and the experimental platform and method is established. The operational characteristic experiment of disconnector with motor actuator under constant PWM is carried out, and the influence of energy-storage capacitor charge voltage on operating speed of disconnector is analyzed. The operational characteristic experiment of disconnector with motor actuator under varied PWM is carried out. The piecewise adjust-speed operational scheme of disconnector is established, and the related experiment is carried out, the VFTO and re-strike process between contacts of disconnector under adjust-speed operation are calculated and analyzed.