Power
Ahmad Ghafari; Mohsen Saniei; Morteza Razzaz; Alireza Saffarian
Abstract
Increasing the penetration level of distributed generation (DG) units in radial power distribution systems can increase the short-circuit level in these networks, which can, in turn, have destructive effects such as exceeding the tolerable current of the equipment and disrupting the protective coordination ...
Read More
Increasing the penetration level of distributed generation (DG) units in radial power distribution systems can increase the short-circuit level in these networks, which can, in turn, have destructive effects such as exceeding the tolerable current of the equipment and disrupting the protective coordination in the network. The active superconducting fault current limiter (ASFCL) is a new device that can limit fault current using voltage series compensation. This paper discusses the modeling of ASFCL and control strategies including fault detection and converter performance in normal and fault modes. Initially, its performance in limiting the fault current is investigated by simulating a sample three-phase system with ASFCL. In the next step, three operating modes including normal mode, upstream fault mode, and downstream fault mode are proposed to achieve an adaptive FCL that solves these problems in grid-connected microgrids. The simulation results confirm the proper performance of the ASFCL modes in both fault current limiting and protective coordination of overcurrent relays in the network.
Power
Ali Rouhipour; Elaheh Mashhour; Mohsen Saniei
Abstract
This paper develops a new model for the optimal placement of switches (both manual and automatic ones) in distribution networks to simultaneously reduce energy loss and improve network security. Expected energy not supplied (EENS) is assumed as the security index, and a method is developed for more exact ...
Read More
This paper develops a new model for the optimal placement of switches (both manual and automatic ones) in distribution networks to simultaneously reduce energy loss and improve network security. Expected energy not supplied (EENS) is assumed as the security index, and a method is developed for more exact calculation of this index regarding drastic climatic changes along with global warming and the resultant effects on both power consumption patterns and power network occurrence. The objective function of the problem is minimizing investment and maintenance costs, the cost of energy loss, and EENS cost. The suggested model can locate optimal places for installing the switches and their seasonal closed and open states so that the total costs can be minimized. The model is implemented on two test networks and evaluated under different scenarios. According to the results, despite the higher costs of automatic switches, the application of automatic switches is more economical in low-security networks for improving network security.