Digital meter and merging unit are widely used equipment in digital substation. At present, many digital power source only can output SV message with low randomness, Can not meet the relevant national and industry standards for the detection of influence quantity of digital energy meters. Aiming at this problem, this paper designs a random sequence generation algorithm based on chaotic map to ensure the random characteristics of the abnormal message outputted from standard digital power source, and output the IEC-61850-9-2 sequence through the FPGA configuration optical port Ethernet chip. The chip is configured as the RMII interface output with the smallest time dispersion to ensure that the message dispersion is controllable. The experimental results show that the digital power source developed has a large information entropy of the sampled random sequence when the guaranteed packet loss probability is controllable. The discrete value is released and the error is less than 20 ns, which is much smaller than the standard 3us. The performance satisfies the detection requirements of the abnormal communication state of the digital energy meter. The equipment has been used to detect digital energy meters in China Southern Power Grid.