The integration of Internet of Things (IoT) technologies into smart grids has revolutionized energy management, but has also introduced significant cybersecurity risks. This survey investigates the role of zero-trust frameworks, blockchain, and Artificial Intelligence (AI) in securing smart grids. The study covers a broad spectrum of emerging threats, including False Data Injection (FDI) attacks, AI-driven generative attacks, and vulnerabilities in blockchain-based systems. In addition, it assesses the effectiveness of current detection techniques and highlights the challenges encountered in securing smart grids against evolving cyber threats. The findings suggest that hybrid approaches integrating Zero Trust Architecture (ZTA), blockchain, and AI-based anomaly detection systems have the potential to significantly improve grid security. However, implementing these solutions on a scale requires addressing challenges such as scalability, energy efficiency, and resilience to adversarial attacks. Finally, the survey identifies gaps in existing research. It proposes directions for future work, focusing on the development of advanced security models that integrate hardware and software solutions for enhanced resilience, scalability, and long-term sustainability.