Computer information has taken over many aspects of everyday life. One of those aspects has been smart grids which have evolved into a more complex system. However, with the advantages that smart grids come with, disadvantages concerning the security of those smart grids. Concerns regarding the compromise of the system have been issues of debate in the recent years. With that said, there are several encryption algorithms that are commonly used to secure and cipher the sensitive data from being stolen or altered. This work presents a survey and a comparison between the most well-known algorithms to help ensure security for those systems. The algorithms that were selected for this work are AES, DES, TDES, E-DES, RSA and BLOWFISH. The comparison is set between to find the effectiveness, key size, complexity and time required between those algorithms. The performance evaluation of these algorithms is evaluated using MATLAB.

High‐voltage direct current (HVDC) transmission systems are nowadays ideal candidates for interconnecting renewable energy resources to the electrical grids. This study presents a communication‐less protection scheme for HVDC transmission systems with a multi‐terminal voltage source converter (VSC). The existence of a tie‐busbar is also considered, which represents a challenge for protection selectivity functions without the aid of a communication channel. The proposed scheme identifies the faulted segment on either a DC busbar or a line segment based on monitoring the calculated rate of change of the current‐to‐voltage ratio. This criterion is sensitive to detect the faults as the current increases rapidly in a few milliseconds, while the voltage decreases in the same time frame remarkably. Once the fault detection criterion is satisfied, the faulted section can be identified by checking the summation and direction of all branch currents at each busbar individually without utilising communication links. For investigation purposes, the proposed scheme is tested via a four‐terminal HVDC system with two tie‐busbars. Different simulation cases are evaluated with a variety of fault conditions using MATLAB/SIMULINK. The results corroborate the reliability, security, and efficacy of the proposed protection scheme for multi‐terminal HVDC transmission systems.

This study integrates earth fault location computation with fault management‐control schemes for distribution networks. To realise this target, a panel substation is located at the lateral outlet. The faulted section is identified precisely via a fault‐location algorithm. Then, isolating the faulted section is accomplished through control signals between the lateral‐panel substation and the faulted section isolators. The service restoration is achieved by a direct communication between the lateral‐panel substation and the feeder primary substation. The proposed fault‐location algorithm is based on the pure fault circuit with the initial condition of the earth fault using the measurements at each lateral panel. For phase‐to‐ground fault, the initial condition is the series connection for the sequence networks from the fault point. For phase‐to‐phase‐to‐ground fault, the initial condition is that the summation of the sequence currents at the fault point is equal to zero. The proposed fault‐location algorithm is, therefore, suitable for equipping distribution systems with distributed generation. Moreover, it is applicable for earthed or unearthed networks with all possibilities of transformer connection and load taps. For investigation purposes, simulation tests are performed using the IEEE 33‐bus automated feeder example. The simulation test results corroborated the efficacy of the proposed fault management system.