A Novel Wide Area Protection Classification Technique for Interconnected Power Grids Based on MATLAB Simulation

Abstract

More recent technological advancements in microprocessor relays, combined with GPS receivers for synchronization and accurate time stamping, is providing users advanced relay systems with synchronized measurements, called synchrophasor measurements (IEEE Power System Relaying Committee, 2002; Phadke, 2002; Marek, 2002). Synchrophasor measurements together with advancements in digital communications, provides users with the power system state at a rate of twenty times per second. Synchrophasor measurements from different network locations when combined and processed in a central computer system will provide users with the absolute phase angle difference between distant network buses with an accuracy of tenths of an electrical degree. These types of central computer systems, equipped with wide-area protection and control algorithms, will be able to better address future system out-of-step conditions and other system problems because they will have a better knowledge of what happens throughout the power system. In addition, knowledge of online generation and load demand provided from synchrophasor measurement systems will aid in balancing better the generation and load during islanding, as well as minimizing load and generation shedding in order to preserve stability during major system disturbances. Time synchronized phasor measurements provide a dynamic view of a power system, combining these measurements in a central protection system (CPS); this capability is used to set up a wide area control, protection and optimization platform by means of new communication systems and (GPS), integrated application design is shown in Figure 1. Figure 1 shows an integrated application design based on phasor measuring units. When the system operates in extreme conditions, load shedding, generation shedding, or system islanding must occur to prevent total system collapse (Thorp et al., 1988; Centen et al., 1993; Guzman et al., 2002; Guzman et al., 2002). Typical causes of system collapse are voltage instability or transient angle instability. These instabilities can occur independently or jointly. In most cases, system wide-area disruptions begin as a voltage stability problem. Because of a failure to take proper actions for the system to recover, this voltage stability problem evolves into an angle stability problem. New monitoring, protection, and communications technologies allow us to implement economical localand wide-area protection systems that minimize risk of wide-area system disruptions or total system collapse.