Smart grids represent a transformative approach to managing energy systems by combining traditional power infrastructure with advanced information and communication technologies. However, the digital nature of smart grids renders them vulnerable to numerous cyber threats, particularly concerning data security. This paper presents a blockchain-based framework tailored to enhance data integrity, confidentiality, and secure access in smart grid environments. The framework employs a permissioned blockchain (Hyperledger Fabric) integrated with smart contracts and Practical Byzantine Fault Tolerance (PBFT) consensus to ensure trustless, tamper-proof, and efficient data transactions. Simulation results demonstrate improvements in latency, throughput, and resilience compared to traditional models. The proposed model offers a scalable and secure solution to meet the evolving demands of smart grid data management.