REJEIÇÃO DE CARGAS PARA CONTROLE DE FREQUÊNCIA DE BARRAMENTO CONECTADOS À GERADORES

Abstract

ArcelorMittal Tubarão's electrical system consists of 2 138kV busbars, 6 generators are connected to these buses, which are driven by steam turbines, steam generated by burning gases produced in the company's own steelmaking process. One of the busbars is connected to the National Interconnected System (SIN) through the local concessionaire (EDP Escelsa), between these buses, circuit breakers (Bustie) with protections were strategically installed so that when there is a possible variation in the National Interconnected System (SIN), the same do the deinterconnection of the AMT x SIN electrical system, protecting the buses that are connected to the generators and all the relevant loads of the plant, this bus is called the generation bus. So that when these circuit breakers (Bustie) open the electrical system, the power flow must be within a pre-defined limit by the capacity of the generators to assume or reject such power. For this type of configuration, it was necessary to install a system that can reject generation or load, so that when it exceeds the pre-defined limit, it is suitable for a safe disconnection. This system is called the “Charge and Generation Rejection System (SRCG)”, which, in addition to rejecting loads and generating for flow control in Bustie circuit breakers, controls the frequency in automatic mode with the system disconnected. The proposal referred to in this article makes the Charge and Generation Rejection System (SRCG) monitor the frequency of the generation bus with the system disconnected, even with the SRCG in manual. With this proposal in place, it is possible to avoid some undesirable losses in ArcelorMittal Tubarão's electrical system, making the electrical system more reliable.