Smart grid is expected to make use of Internet-of-Things (IoT) networks to reliably monitor its state from remote places.However, due to a potentially unstable nature of a smart grid plant, in particular, when using renewable energy sources, and an unreliable wireless channel used in IoT, it is a challenging task to reliably track the state of smart grids. This article proposes a robust communication framework for state estimation/tracking of unstable microgrids, which is a key component of a smart grid. We present an IoT-integrated smart grid system to monitor the status of microgrids over a wireless network. A delay-universal-based error correction code is utilized to achieve a reliable and real-time estimation of microgrids. To exploit the features of the delay-universal coding scheme, we propose an iterative estimation technique. Through numerical results, we show that the proposed scheme can closely track the state of an unstable microgrid. We also show the impact of wireless network parameters on the estimation performance. The estimation performance of the proposed scheme is compared with the estimation performance of a traditional error correction coding scheme. We show that the proposed scheme substantially outperforms the traditional scheme.