Frequency response analysis (FRA) is a technique used to diagnose the mechanical integrity of a transformer winding; such diagnostic tools can be of enormous value since power transformers are a critical asset within any electrical network. To minimize the probability of an unexpected outage, or prevent a catastrophic failure, maintenance and monitoring of power transformers is essential for utilities. Over the past couple of decades, FRA has been utilized as an off-line diagnosis method. However, with the recent development in smart grid systems, there is now a growing interest in the development of on-line FRA techniques. This paper proposes a technique for inservice monitoring of power transformer winding deformation, which uses a broad frequency sine wave voltage excitation signal and high frequency Current Transformers (CT) in conjunction with the bushings test taps. Experiments using this system were conducted and then validated on a single-phase 22kV/110V voltage transformer.

The rise of cyber threats on critical infrastructure and its potential for devastating consequences, has significantly increased. The dependency of new power grid technology on information, data analytic and communication systems make the entire electricity network vulnerable to cyber threats. Power transformers play a critical role within the power grid and are now commonly enhanced through factory add-ons or intelligent monitoring systems added later to improve the condition monitoring of critical and long lead time assets such as transformers. However, the increased connectivity of those power transformers opens the door to more cyber attacks. Therefore, the need to detect and prevent cyber threats is becoming critical. The first step towards that would be a deeper understanding of the potential cyber-attacks landscape against power transformers. Much of the existing literature pays attention to smart equipment within electricity distribution networks, and most methods proposed are based on model-based detection algorithms. Moreover, only a few of these works address the security vulnerabilities of power elements, especially transformers within the transmission network. To the best of our knowledge, there is no study in the literature that systematically investigate the cybersecurity challenges against the newly emerged smart transformers. This paper addresses this shortcoming by exploring the vulnerabilities and the attack vectors of power transformers within electricity networks, the possible attack scenarios and the risks associated with these attacks.

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