Broadband PLC network is potentially used to deploy synchrophasor-sensor network in monitoring and distributedly controlling the electric power distribution network in order to accelerate power grid into smart grid transform. However, data traffic characteristic is largely affected by either electric power system dynamics or electric power load variation. Therefore, the statistical data information of network condition is an important issue of electric power distribution network. However, measly research is working out of this area . Hence, this paper proposes data traffic from the entire node sensors arriving at intermediate buffer as a queuing model which is approached by Batch Markov Arrival Process (BMAP), and is analyzed as packet loss queuing in finite buffer. Single channel output transmission of the buffer is viewed as single server of queue within Asynchronous Time Division Multiple Access (ATDMA) scheme. The finite buffer size affects data packet loss. The severe packet loss occurs whenever the data packet arrived continuously at a full buffer. Based on our simulation for arrival rate 30 up to 35 Mbps, it shows that at buffer capacity of 4 MB and 16 MB, data packet-loss probability arises rapidly within 3.0 % and 0.08 %, respectively. The large data packet loss probability occurs when the arrival rate quite heavy, about 48 to 49 Mbps, in such conditions increasing buffer capacity offers very small improvement to packet loss.