# A Trust-Influenced Smart Grid: A Survey and a Proposal
## 8 MASs with Trust in the Smart Grid
### Research Areas  
[PERSON] et al. [71] implemented both direct-based and reputation-based trust mechanisms to create a modified version of the contract net protocol (CNP) [72]. The new trust-based CNP model, which was implemented in distributed MAS architecture, was used in Smart Grid scheduling to ensure improved decision quality which led to improved energy efficiency. With the direct trust mechanism, the time and rating value of the trustee were used to calculate the direct trust. These values are stored individually by each agent. The recommendation trust requires the trust rating of the trustee from all other agents in the MAS. The values generated by the trust mechanisms are fed into the CNP model, which is used to calculate which agent a task is delegated to. The model was tested via simulation usingJADE; therefore, a real-world test was not made. This model has not been tested against trust model-related attacks.  
In another paper, an MAS-based negotiation mechanism was implemented to combat jamming attacks in the Smart Grid power market [73]. Their work involved using the trust-based CNP [71] during local marginal price (LMP) [74] negotiations. Their work was simulated on a PJM 5-bus system [75], and it was not tested against any trust-related attacks.  
[PERSON] et al. implemented a trust model in testing the resilience of control systems in power purchasing in cyber-physical systems [76]. The trust is used to calculate the cost of power to be sold by a producer agent to a consumer agent based on the trust level of the consumer. The model was tested using the JADE and GridLab-D power distribution and analysis tool [77].  
In another study, trust was used in the secure operation of state estimation algorithms in networked microgrids [78]. Each microgrid within the network was modelled as an agent. Each agent implements direct trust when an agent provides state estimation values that are below a certain threshold. A malicious node is then isolated by the peer agents from the network. The historical data based on which the behaviour of a node was based are not specified, and the tool used for simulation was also not specified. Their work was not tested against trust-related attacks to test its resilience.  
[PERSON] et al. [79] proposed a trust-based security mechanism for protecting the state estimation process against false data injection attacks by using a multi-agent filtering scheme. The agents assign a trust metric that is used to disregard messages from low-trusted agents. The mechanism involved a mathematical simulation and was not tested against trust-related attacks. [PERSON] et al. [80] wanted to see the impact of trust in a hierarchical agent-based socio-technical system. They ran a scenario replicating the 2003 Northeast Blackout which, in the history of North America, was the largest blackout [81]. The system is comprised of the elements responsible for the handling of the blackout. Each element was identified as an agent. The trust value was a score based on how an agent successfully or unsuccessfully handled a task. Their work was simulated using JADE, and it was not tested against any trust-related attacks. [PERSON] et al. [82] implemented trust in the inclusion of DERs in Smart Grid. The update of the trust score of an agent was dependent on the adherence to the Service License Agreement between it and other agents. Their work was simulated using the JACK-AOS [83] multi-agent platform and was not tested against trust-related attacks.  
[PERSON] et al. [84] implemented reputation-based trust in an agent-based backup protection scheme that aims to mitigate the effects of faults and faulty agents in substations. Their work was simulated using NS-2 [85], EPOCHS [86] and PSCAD/EMTDC [87] but was not tested against trust-related attacks.