Comparative study of GA & DE algorithm for the economic operation of a power system using FACTS devices

Abstract

The problem of improving the voltage profile and reducing power loss in electrical networks must be solved in an optimal manner. This paper deals with comparative study of Genetic Algorithm (GA) and Differential Evolution (DE) based algorithm for the optimal allocation of multiple FACTS (Flexible AC Transmission System) devices in an interconnected power system for the economic operation as well as to enhance loadability of lines. Proper placement of FACTS devices like Static VAr Compensator (SVC), Thyristor Controlled Switched Capacitor (TCSC) and controlling reactive generations of the generators and transformer tap settings simultaneously improves the system performance greatly using the proposed approach. These GA & DE based methods are applied on standard IEEE 30 bus system. The system is reactively loaded starting from base to 200% of base load. FACTS devices are installed in the different locations of the power system and system performance is observed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. GA and DE based algorithm is then applied to find the amount of magnitudes of the FACTS devices. Finally the comparison between these two techniques for the placement of FACTS devices are presented. NomenclatureR Line -Resistance of line; X Line -Reactance of line; Z Line -Line Impedance; X ij -Reactance between i th & j th node; X TCSC -Reactance of TCSC; G TCSC -Real part of Admittance of TCSC; B TCSC -Imaginary part of Admittance of TCSC; r TCSC -Coefficient which represents the compensation degree of TCSC; X C -Capacitive reactance of SVC reactor bank; X L -Inductive reactance of SVC reactor bank; á -Firing angle of SVC; X SVC -Reactance of SVC; S -Operating range of FACTS devices; C TOTAL -Total cost of system operation; C 1 (E) -Cost due to energy loss; C 2 (F) -Total investment cost of the FACTS Devices; min ni p , max ni pLower and Upper limit of nodal active power in the i th bus respectively; P ni , Q niNodal active and reactive power output of the i th bus respectively; min ni Q , max ni Q -Lower and Upper limit of nodal reactive power in the i th bus respectively; min gi Q max gi Q -Lower and Upper limit of existing nodal reactive capacity in the i th bus respectively; Q gi -Output of existing nodal reactive capacity in the i th bus; P Gi , Q Gi -Active and Reactive power generation in the i th bus respectively; P Di , Q Di -Active and Reactive power consumed by load in the i th bus respectively; P i , Q i(inj) -Real and Unauthenticated Download Date | 8/24/15 11:50 AM