The last section of this review series is based on an investigation about security concerns which may become an issue in a fully automated and active DR programs within the smart grid. Due to the fact that we are all connected via the internet, the risk of invasion of householders’ privacy from remote locations in order to steal vital information or to disrupt system operations is a cause for worry. This attack could be evident on any of the data sources and this includes the load profile data as well as the pricing data within the household.
An evidence of cyber-attack on the grid manifested on December 23 2015, whereby there was a recorded incident of attack on the Ukrainian reginal electricity distribution company where seven 110kV and twenty three 35 kV substations were disconnected for three hours [93]. This attack was attributed to foreign government-sponsored cyber-criminals who remotely controlled the SCADA distribution management system and caused blackout on approximately 225,000 customers. Such is an example of the numerous threats which cyber criminals oftentimes pose to the grid network, the vulnerabilities and the disturbing disadvantages of being all connected via the internet. Protection of vulnerable loads and other related components of the smart grid
from such attack keeps attracting interests from researchers around the globe due to the numerous challenges facing the internet world. In this section, the review is based on several authors’ contributions towards improved security of the grid network by highlighting the possible impacts that may be caused, as well as possible solutions available.
The authors in [94] [95] discussed the importance of detecting cyber-attacks in energy consumption data of power systems as provided by smart meters, and suggested schemes for adequate protection. Such attacks on dynamic loads known as: Dynamic Load Altering Attacks (D-LAA), was considered because the possibility to control loads dynamically implies also, the possibility to attack loads dynamically [95]. The paper suggested optimisation problem formulation, solution method and protection system design under uncertainty as approaches towards applying adequate protection schemes to hinder successful attacks on the load data. In contrast, Static Load Altering Attacks (S-LAA) is more common and is based on changing the volume of certain vulnerable loads, usually in an abrupt fashion. The paper suggested that the detection D-LAAs is possible by applying frequency domain analysis of the load profile using spectral analysis of the Fast Fourier Transform (FFT) of the original load profiles.
Another detection technique includes Real-time detection in frequency domain using Windowed-FFT (W-FFT), and detection based on both load and frequency signals [96], [97]. The paper suggested optimisation problem formulation, solution method and protection system design under uncertainty as approaches towards applying adequate protection schemes to hinder successful attacks on the load data.
Authors in [98] investigated the impact of price modification attack in smart grid and possible protection scheme capable of mitigating such attack. This attack was visualized based on the online reliance of pricing information by users who may be interested in reducing energy costs and possibly participating in DR programs. The attack model was based on false price injection on the actual pricing data which may trigger potential load altering attacks, thereby exposing the automated residential load control and increasing peak demand. The attacking scheme was formulated by failing as many transmission lines as possible due to the modified price and then a comparison is made about the effect of considering the impact of the attack when there is a cascading failure as well as when there is no cascading failure. In the cascading mode, the authors in [99] showed that the failure of a single node within the system is capable of causing load redistribution to the other nodes, which could lead to large global power failures. Nevertheless, several efficient protection scheme are successfully implemented which included the allocation of load protection resources to demand nodes in order to make such attacks unattractive.
The authors in [100] investigated the attack vectors on smart home systems analysed on a DigitalSTORM installation using solution-based analysis. This was done by identifying and ranking of possible attack vectors or entry points into a smart home system and suggested ways of thwarting such attacks. Those entry points included: the server, communication bus, smart control device (e.g. smartphone or control station) and remote third party services which provides monitoring and control services. Two theoretical attack scenarios were described and in both cases, a malicious app was
surreptitiously installed on the home owner’s android smart-phone and was used as entry vector which either turns appliances ON and OFF without the home owners’ consent, or collects vital information from the household such as the load profile . For burglars, such information could be used to determine when to burgle such households. The authors recognized the merits of ensuring a secured smart home system which should include requesting some form of authentication from authorized users before obtaining access to perform any activity within the home.
Finally, the authors in [101] improved mesh network security used within various smart grid domains against cyber-attack by introducing a dynamically updating key distribution strategy on network protocols. The proposed method was mainly designed against Denial of Service (DoS) attack by utilizing a 4-way Merkle-tree based handshaking scheme. The reliability of the model was verified using Proverif and they were able to demonstrate the effectiveness of key refreshment strategy in thwarting DoS attack on the smart grid network.
Several other forms of cyber-attack are possible and may include communication system failure which could originate from the utility or from the localized HEMS [3]. For any type of attack that is capable of forcing all the consumer’s appliances to turn on at the same time portrays a potential to cause the grid to become congested which can also force it to a collapse. This type of attack or virtually any type of cyber-attack poses an immense security threat since potential terrorists can congest the grid to such a level that it succumbs and fails thereby giving these nefarious groups the appropriate environment to
execute their terrorism intent. Therefore an analysis of the impact of the various types of cyber-attack could have on a household, as well as on the grid is included in this thesis. Proposals to the possible ways to identifying these treats are made and means to mitigate their effect when detected also suggested.