Load flow model for UPFC with ESS and ATC determination

Abstract

A load flow analysis is used for planning and to determine the transmission constraints in the existing networks. The load flow solution gives information about the magnitude and phase angle of the voltage at each bus and real and reactive power flows in each line for given generation, load and transmission network data. By using Flexible AC Transmission System (FACTS) devices namely Unified Power Flow Controller (UPFC) will gives a basic control for transmission line real/reactive power flow and bus voltage/shunt reactive power. UPFC with ESS helps in regulating the power and mitigating the rotor speed instability and damping oscillations. UPFC placement was conducted at each line in the entire network system together with ESS to obtain the most suitable optimum location for most effectiveness performance. The performance of the optimal UPFC and ESS location is checked by applying a fault across a transmission line to which UPFC is connected and the power flow in the line and stability of the system is determined. Available Transfer Capability values indicate allowable highest magnitude of active power (MW) that can be transferred from the source to the sink over and above the already committed uses (base case) of the whole network without exceeding any line thermal loading and bus voltage limits. Finally, simulations were carried out using PSAT software to validate the performance of the UPFC and ESS connected to a transmission line. The effectiveness for UPFC and ESS are demonstrated on IEEE 9 bus and IEEE 24 bus system while for ATC is demonstrated on IEEE 6 bus system and all the results are compared.