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The IUP Journal of Electrical and Electronics Engineering:
A Look Ahead Load Shed Strategy for Line Overload Alleviation Based on the Sensitivity of a Severity Index Incorporating Distributed Generations
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The paper describes a new methodology for load shed at buses incorporating the effect of Distributed Generation (DG) at selected buses. The strategy gives load shed amount at selected buses in anticipation of the predicted load in the next interval. The method first exploits the capability of DG present at various buses for achieving line overload alleviation and then, if necessary, load shed is executed at load buses. It is a monovariable method, where load shed is executed at buses having the highest sensitivity of Severity Index (SI), and then another bus is selected in the next iteration based on the magnitude of sensitivities. The algorithm has been implemented on a 30-bus test system.

 
 

Various security levels based on the operating conditions of a power system were defined by Stott et al. (1987). ‘Secure’ and ‘correctively secure’ status provide safe operating conditions. Disturbances in the system, e.g., component outages, load increase will bring in the system various unsecure operating conditions. These unsecure emergency states are alert, correctable emergency and non-correctable emergency. Violations of operating constraints, e.g., bus voltage magnitudes, line flows and voltage stability margin are alleviated by rescheduling usual real and reactive power control variables if the system operates in alert and correctable state. Unusual control action as line switching is executed for alleviation of line overloads or rotation of overload at times if system capability permits (Arya et al., 2000). If the system lends up in non-correctable emergency state, then load shedding is the only remedy to make the operation of system secure. At times, at selected buses, Distributed Generation (DG) is available in standby mode which may be strategically brought into the picture for alleviating operating limit violations (Bae et al., 2004; Arya et al., 2012a; and Arya, 2014). Hence the option of DG should be taken into consideration along with load shedding at a few buses so as to reduce the total load shed amount. Load shedding may be required to fulfill various different objectives, e.g., thermal limit violations, voltage/voltage stability margin and frequency limit violation. It is kept in mind that load shed takes place at selected buses which causes total load shed amount minimum and should not cause inconvenience to a large number of consumers.

 
 
 

Electrical and Electronics Engineering Journal,Load shed, Severity Index (SI), Jacobian, Sensitivity, Line overload alleviation, Distributed Generation (DG).