Enhancement of Synchronized Power Grid Sampling Utilizing Diophantine Approximation- Based Interpolation Filter Bank

Accurate synchronized sampling is essential for power grid monitoring instruments, but its precision is greatly affected by sampling time errors (STEs) resulting from oscillator frequency drift. However, existing methods to mitigate STEs often rely on additional auxiliary devices or involve complex hardware control processes. Therefore, this article introduces a novel sampling scheme that effectively mitigates the impact of STEs without the aforementioned restrictions. First, the actual sampling interval is estimated via a counter triggered by the satellite timing reference. Second, the actual sampling interval is fed into the Diophantine approximation method to determine the sampling interval conversion ratio (SICR). Finally, an IFB is constructed according to the SICR to rectify the sampling data contaminated by the STE. A series of simulation and hardware experiments are conducted to verify the effectiveness of the proposed DA-IFB. The test results demonstrate that the proposed DA-IFB is comparable to the state-of-the-art synchronized sampling method without any additional requirements, with maximum sampling error significantly mitigating from
$2.16 \times 10^{-3}$

$\mathrm{V}$
to
$7.18 \times 10^{-5}$

$\mathrm{V}$
.