Original scientific paperDue to the rising power demand and increasing population worldwide, electrical power networks have been extensively growing and striving to satisfy the escalating loads. This necessitates the need for using Flexible AC Transmission System (FACTS) devices which have become indispensable during normal and abnormal operating conditions. This paper investigates the impact of using series FACTS devices, namely Thyristor Controlled Series Capacitor (TCSC), GTO Controlled Series Capacitor (GCSC) and Thyristor Controlled Series Reactor (TCSR), on the impedance and power flow of a practical 400 kV transmission line in the Algerian power network. It also investigates the effect of varying the fault resistance on short-circuit calculations in the case of a phase to ground fault that occurs at the end of the compensated line. Analytical formulas of the employed FACTS devices, the system model under fault and short-circuit calculations are deduced and presented in the paper. Simulations results obtained using MATLAB are demonstrated for the compensated line and without compensation. These simulations are compared to show the effect of using these devices for the studied cases.It is concluded that GCSC provides better performance in the active and reactive power flow of the line under normal operating conditions and in reducing the fault current during abnormal operating conditions when the fault resistance increases. On the other hand, TCSR shows a better performance in maintaining higher voltages under fault with the increase of fault resistance.Key words: Thyristor Controlled Series Capacitor (TCSC), GTO Controlled Series Capacitor (GCSC), Thyristor Controlled Series Reactor (TCSR), Algerian power network, Phase to ground fault, Fault resistance, Short-circuit calculations.Usporedna analiza greške uzemljenja za praktični slučaj transmisijske linije s različitim FACTS uređajima. Zbog rastuće potražnje za električnom energijom i porasta svjetske populacije elektroenergetske mreže ubrzano rastu i podnose sve veće terete. Takav razvoj situacije doveo je do korištenja fleksibilnih AC transmisijskih sustava (FACTS) koji su postali nezamjenjivi tijekom normalnih i narušenih uvjeta na mreži. U ovom se radu istražuje utjecaj korištenja FACTS uređaja, tiristorski upravljani serijski kondenzatori, GTO upravljani serijski kondenzatori i tiristorski upravljana serijska reaktancija, na impedanciju i tok snage kod 400 kV transmisijske lijene u alžirskom elektroenergetskom sustavu. Istražuje se i utjecaj promjene otpora greške pri izračunu kratkog spoja u slučaju spoja faze na zemlju koje se događa na krajevima linije. Analitičke formule korištenog FACTS uređaja, model sustava s greškom i izračun kratkog spoja su izvedeni i prikazani u radu. Simulacijski rezultati dobiveni korištenjem MATLB-a prikazani su za linije sa i bez kompenzacije. Simulacije su uspoređene kako bi se prikazao učinak korištenja različitih uređaja. Zaključeno je da GTO upravljani serijski kondenzatori ima bolja svojstva kod toka radne i jalove...