This paper focuses on enhancing IEEE 802.11e EDCA for improving reliability in Smart grid networks. 802.11e can support prioritized QoS to differentiate traffic and guarantee fairness for delay-stringent applications. However, this may pose serious problems when applied to Smart Grid environments which support applications that have strict reliability requirements. To solve this problem, we suggest a contention mitigated EDCA algorithm (CM-EDCA), which utilizes packet collision and MAC retransmission parameters to change the packet priority and reduce packet collisions. The proposed scheme is compatible with IEEE 802.11e and easy to implement for Smart grid devices. Simulation studies show improved reliability compared to the existing methods in IEEE 802.11e.