Protection of Power Semiconductors in Inverters, using Fuses and their Coordination with the Protection Schemes of the Distribution System

Abstract

The integration of Distributed Energy Resources (DER) implies an important challenge for the protection of the distribution network, due to the incorporation of devices with less capacity to withstand normal disturbances in distribution systems, particularly for overcurrents and overvoltages. The increasingly widespread use of power electronics, incorporated in rectifiers and inverters, which due to its weakness requires highspeed protection devices, complicates coordination with the traditional protection of distribution systems. Converters (rectifiers and inverters) require ultra-fast protection against high current faults, conditions that currently only meet high breaking capacity fuses. The response characteristics of these ultra-fast fuses, oblige the professional in charge of the protection of the distribution system to have a deep knowledge about the behavior of the power electronics in the face of overcurrents, and to know also how the fuses, through the selection of its rated values and characteristic curves protects it. Coordination of the rating values and characteristics of these fuses with their counterparts (when they exist) of traditional protection devices is the main objective of this article. Particular terms are explained in detail, such as fault current asymmetry and its effect on the coordination of protections, specific energy, etc. It is concluded that deep knowledge of the dissimilar characteristics of power electronics devices and the usual devices of distribution networks, with regard to their protections, are essential to obtain a maximum use of the traditional scheme with the addition of DER.

A Review of Protection Schemes for Electrical Distribution Networks with Green Distributed Generation

“…A significant challenge in protection after GDG integration with DNs is due to the increased use of power electronics represented by rectifiers and inverters, which require high speed PDs. For that, ultra-fast fuses with a presumed ratio of the largest to smallest section of the fuse element must be designed to obtain a wide range of ordinary protection blueprints [77]. This approach needs to use technological programs to satisfy the need for less time for analyses.…”

“…This protection must be supplemented by external PDs to avoid damage to the inverter by the energy supplied by the grid (for AC) and by the source (for AC and DC) [77]. The integration of a GDG with this feeder type causes many protection problems.…”