A feasibility study for a fault current limiter to reduce voltage sags at sensible loads

In relatively weak networks, a fault occurring in any part of the network causes voltage sags to appear in different nodes, more severely in those adjacent to the fault. One way to reduce these voltage sags to acceptable values can be achieved by limiting the fault current in the distribution feeders. A fault current limiter is defined as a series device that presents a low impedance to steady state currents, but acts quickly to limit the instantaneous magnitude of a fault current to a predetermined value. One of the Mexican utilities, Luz y Fuerza del Centro, supplies electricity to the central part of the country, including Mexico City. Some of its industrial customers suffer from these voltage sags with the corresponding equipment outage and loss of production. The utility has identified several 23 kV feeders, which are "responsible" for tripping sensitive loads. One of these feeders was chosen to perform the feasibility studies. This paper presents the major aspects of an investigation consisting of the parameter of the resonant link, simulations for different types of faults, sensitivity analysis and final recommendations