| 摘要 |
19 CORRECTION PROCEDURE OF THE PHASE DIFFERENCE INTRODUCED BY A ZERO SEQUENCE MEASUREMENT TOROID OF A LEAKAGE CURRENT AND ISOLATION MONITOR IMPLEMENTING THIS PROCEDURE A digital isolation monitor comprises a signal processor operating in conjunction with a measuring circuit to perform a first no-load measurement and a second load measurement of a zero sequence signal delivered by a toroid of a differential transformer, followed by synchronous demodulation. A microcontroller computes the tangent of the angle of phase difference introduced by the toroid by computing the relationship between the load and no-load components, and determines the true values of the leakage resistance and stray capacitance of the power system.
|
