Comparative study of the effects of series and parallel compensations on distance protection of transmission lines

The Flexible Alternating Current Transmission Systems (FACTS) devices have great use in the Electric Power System (EPS) regarding the dynamic control of the active and reactive powers of the system, resulting in greater efficiency of the generated electrical energy. However, the insertion of such devices affects the performance of the impedance protection of TLs, as founded in literature in the last years. This paper deals to present a comparative analysis between the effects caused in a real distance protection device of transmission lines (TLs) by two of these devices: the Static Synchronous Compensator (STATCOM) and the Static Synchronous Series Compensator (SSSC). Computational simulations with the aid of the PSCAD/EMTDC software were made, where both the electrical system under analysis and the two FACTS devices were modeled. With the representation of the machines and transmission lines that make up the analyzed set, the protection zones for one of these lines were defined. After the section was protected, STATCOM and SSSC were inserted and short circuits between phases and between phase and ground were applied, both in the presence and in the absence of the studied FACTS to create a database for comparative analysis. Once the effects of FACTS devices on distance protection in a simulation environment were verified, laboratory tests were carried out to ensure compliance concerning the results.