This article studies a smart grid dynamic wide area network where a friendly jammer is proposed to enhance the secrecy of the network. In the network, the smart meter (SM) in each household communicates with the full-duplex meter data control unit (FD-MDCU) via a decode-and-forward data aggregation unit in the presence of an eavesdropper. To improve the security of the network, the FD-MDCU transmits jammer signal which interfere with the eavesdropper. It is assumed that all the household are not sending data at the same time, thus Markov chain is employed to model the number of active SM. Thus, to evaluate the performance of the proposed network, the closed-form expressions of connection outage probability (COP), security outage probability, and secrecy throughput metrics are obtained. Moreover, more insight about the network performance is provide by obtaining the COP asymptotic expression at high signal-to-noise ratio. Also, the accuracy of the derived expressions is justified by Monte-Carlo simulations. Our findings demonstrate the impact of network and channel parameters on the network security performance.