Dynamic Stability Improving at Industrial Electrical Systems through the use of Variable Load Shedding Schemes

This paper presents results obtained from dynamic studies performed on industrial facilities, focused on chemical and petrochemical power systems. Many internal processes require of thermal resources as gas or steam to maintain their production level. Consequently, the generating units often modify its generation dispatching as a result of the plant´s current operation condition and limitations of thermal resources pointed out before. The purpose is to improve dynamic response of the system during electrical system disturbances, setting appropriate variable load shedding schemes for different generating dispatches scenarios. In order to achieve this, dynamic simulations were done, and considering the characteristics of an automatic generation control (AGC) and of solid state multifunction relays with independent setting groups, a variable load shedding scheme was adjusted. These variable schemes improve electrical system performance against disturbances at external system that cause internal load-generation unbalances