Occurrence of large power deficits are the main cause of black outs in power systems. Usually, large power deficits occure as a result of large generating units or tie-lines outage. Considering the impact of electricity on economic growth of countries and daily life of people, triggering a blackout might be a goal of sabotage or military attacks.Underfrequency LOAD SHEDDING is commonly used to prevent blackout in case of large power defcits. In fact by curtailing part of the LOADs, LOAD SHEDDING schemes retain the power balance and keep the system stability. In this paper, an underfrequency LOAD SHEDDING method based on wide area monitoring system is proposed. In this LOAD SHEDDING scheme, the amount of LOAD to be shed, in case of large power deficits, to preserve the stability of power system is determined based on the estimated minimum frequency. The effectiveness of the proposed method in different conditions, considering power system parameters variation, is proved using simulation studies.

LOAD SHEDDING is the last line of defense for controlling and stabilizing of the power system in the occurrence of a disturbance. Determining the amount and location of the LOAD SHEDDING are issues that the power system operators always have faced In this paper, a new method is proposed for determining the location of under voltage LOAD SHEDDING (UVLS). The proposed method, unlike the previous UVLS methods, uses two different factors to determine the effective location of UVLS. Considering the LOAD reactive power in the process of determination of the UVLS location leads to disconnecting more reactive power during the initial steps of UVLS. Therefore, less active power sheds by the UVLS. To verify the accuracy of the proposed method, the proposed UVLS method accompanied with the method which uses the sensitivity of voltage with respect to the active power are implemented in IEEE 118-bus test system and New England 39 bus system. The obtained results show the superiority of the proposed method.

One of the most important tasks of operators in distribution companies is to restoration after a fault in the network. In LOAD restoration schemes, in addition to observing the LOAD flow constraints, it is necessary to maintain the grid structure radially and, most importantly, observing the balance of consumption with the possibility of providing LOAD due to the limitations of the backup feeder (or distributed resource constraints). This paper presents a new approach called smart LOAD SHEDDING in distribution networks, which aims to design a smart LOAD SHEDDING module in situations where it is not possible to provide LOAD after a network failure. In this case, the network LOAD restoration will be provided at the lowest outage cost and in the shortest possible time to maximize customer satisfaction. In order to validate the proposed method, the level of automation of the sample distribution network for smart control of LOADs is defined in three scenarios. The types of LOADs available in smart homes are also prioritized and categorized into three categories of adjustable, interruptible, and shiftable LOADs. The proposed method is coded in the MATLAB software environment. To demonstrate the effectiveness of the proposed model, simulation is implemented on an RBTS system. The results show the effectiveness of the proposed method in reducing costs and improving the restoration management of the distribution system.

The benefits of renewable energy have led to the increased penetration of Distributed Generators (DG) not only in the military sites، but have also increased the availability of continuous supply of electrical energy even in the critical conditions. During the national grid supply interruption، the stability of these systems (micro grid) is essential. In order to maintain frequency stability of these isolated micro grids، a balance between generation and consumption has to be always maintained. It is customary to use energy saving devices to maintain balance by increasing generation in the short runs، where large frequency deviation results in LOAD SHEDDING. In this paper use of interruptible/curtailable LOADs to maintain the balance is proposed. That is a specific LOAD has been reduced to control the frequency. Simulation of the proposed method has been run on the model of a real network which has verified the results and its effectiveness

This paper describes a methodology for obtaining minimum LOAD-shed at selected buses from voltage stability margin viewpoint. The buses for LOAD-shed have been selected based on line voltage stability index and its sensitivities at operating point. Computational algorithms for minimum LOAD-shed have been developed using conventional particle swarm optimization (PSO) and coordinated aggregation based particle swarm optimization (CAPSO) one of its variant. Using these two algorithms LOAD-shed results for two sample test systems have been obtained and compared.

The stability of frequency and voltage is one of the basic principles in the power systems. One of the latest control measures for power system frequency control and stability is LOAD SHEDDING. A fast and optimal adaptive LOAD SHEDDING method using Artificial Neural Networks (ANN) is presented in this paper. In this paper, the total power generation and the total existing LOAD in power system were selected as the ANN inputs. This method has been tested on the New England test system. The simulation results show the ability of this frequency control algorithm for optimal solving problem related to conventional method.