| As an important power equipment in power system,dry hollow reactor is mainly used to limit short-circuit current and absorb capacitive reactive power in the grid.It not only reduces the line loss and improves the power transmission quality,but also is widely used in the power system by virtue of its linear reactance value,simple structure,light weight and convenient installation,and ensure the safe and stable operation of the power system.However,since the reactor has been put into operation,the reactor has been burnt down due to its long-term working in high voltage environment,and often accompanied by partial discharge,turn-to-turn short circuit and other faults caused by turn-to-turn insulation defects.In order to reduce the fault rate of reactor,it is necessary to put forward effective fault detection methods.In addition,the current fault detection methods generally have the disadvantage of low sensitivity,which improves the uncertainty of reactor fault detection and affects the normal operation of the system.Therefore,it is of great engineering significance to explore more reliable or more sensitive fault detection methods.In this paper,the spatial magnetic field around the reactor is taken as a kind of signal,and the operation state of the reactor is monitored by the distribution law of the surrounding spatial magnetic field.At present,the research on this method is still in the exploratory stage.To solve this problem,the physical model of dry hollow reactor under normal state and different short-circuit fault states is established in this paper,on this basis,the mathematical analytical models of the currents of the winding with different encapsulations and the analytical models of the spatial magnetic field are obtained by using the analytical method,and the use of MATLAB prepared the inductance and magnetic field calculation program,In order to avoid the disadvantages of large amount of calculation and slow running speed,the finite element method is finally used to study the magnetic field of the dry hollow reactor.Secondly,the 2-d finite element model of 66 kV dry hollow reactor is established by using ANSYS software,and the calculation results of analytical calculation method and finite element analysis method are compared by combining the field-circuit coupling analysis model,so as to verify the correctness of the field-circuit coupling model.At the same time,aiming at the short circuit fault that often occurs in the operation process of the reactor,the operation state of the reactor when short circuitoccurs in different positions of different packages is simulated,the distribution rules of flux density and magnetic field lines under different fault states and the variation rules of fault currents at different locations are obtained.Finally,the experimental platform was built to conduct experimental research on the reactor short-circuit model from two aspects of steady state and transient state.The steady-state data and transient waveform of the winding fault current were analyzed,and the relationship between the fault current and the short-circuit position was obtained,and compared with the simulation rules,so as to verify the feasibility of the method.It not only provides a reference for the effective monitoring of reactor faults,but also provides a new idea and theoretical basis for the safe and stable operation of the power system and the manufacture of reactors. |
