With the promotion of the carbon peaking and carbon neutrality goals, the large grid flexible AC and DC transmission gradually become the mainstream technology, the power system is increasingly showing the Double High characteristics, a high proportion of power electronic equipment and a high proportion of new energy will bring more serious harmonic problems. Existing filtering devices must be connected in series or parallel to the line, that is, with the circuit to produce electrical contact. Traditional passive filters, although highly reliable, are large, poorly controllable, cannot realize dynamic compensation, and can only compensate for specified harmonics. Although the active filter device overcomes the disadvantages of passive filter device, but the existence of power electronic devices have the problem of inherent low reliability, once the failure will directly affect the normal operation of the power grid, reducing the reliability of power grid operation. In view of the above problems, this paper proposes a new type of high-reliability plug-and-play active power filter based on hybrid flux control, whose unique open-close structural design greatly simplifies the access procedure, realizes plug-and-play, and does not affect the structure of the power grid itself after accessing it, and does not affect the normal operation of the power grid even if it goes off the grid, so it has high reliability.