Generally, such systems are more and more dependent on the communication infrastructure and hence become more and more vulnerable to cyberattacks. They can target dependencies upon communicated signals, resulting in serious operational interferences such as cascading failures and blackouts. The following paper attempts to present an assertive case for proper defence mechanisms against false-data injection cyberattacks to protect load–frequency control mechanisms. To this end, we introduce a new safety–critical controller using control barrier functions to promote system robustness against adversarial tampering. The method of the proposed controller also builds safe sets that specify safe limits of the operation, thereby eliminating the undesirable dynamic that might have been caused by maladjusted signals. We also show that this approach successfully reduces the above expressions of attacks aimed at false relay operations concerning frequency and rate of change of frequency protection schemes. In this chapter, we prove how the controller performs cyber defence in conjunction with the conventional testing and stabilization mechanisms in power systems by conducting extensive simulations and real-world tests on a high-fidelity controller testbed. Our findings suggest that the introduction of control barrier functions can effectively reduce instability and generation loss in cyberattack settings. Furthermore, it can be integrated into the existing power system structures without complicating the designs and making broad changes. This work benefited the field of power system security by presenting action plan to address new security threats posed by cyber actors as an appropriate preventive measure for power systems despite escalating cyber risks to power system security and energy delivery. The results can trigger concept development and implementation of superior control methodologies to increase the reliability of the power systems against possible cyber threats in the future.