Search

Static synchronous compensator (STATCOM), a shunt type flexible AC transmission system device, is used to control the voltage at different locations within a power system by absorbing/injecting reactive power. The dynamic control action associated with the operation of STATCOM in both capacitive and inductive modes is the reason for varying system condition and failure of different relaying schemes. Directional relaying is affected by the reactive current contributed by STATCOM in wide range of inductive to capacitive mode of operation. Further, single pole tripping (SPT) condition during STATCOM operation leads to mal‐function of the directional element due to phase change in sequence components of voltage and current. In this study, directional relaying is addressed for different types of faults in the presence of STATCOM connected at different locations during single phase auto reclosing period. Proposed directional relaying technique is based on the phase angle between positive sequence fault and pre‐fault apparent powers. Performance of the proposed scheme has been investigated for different types of faults for single and double circuit lines during SPT using simulated data of different power networks using PSCAD/EMTDC software. A comparative study is also carried out to verify the performance of the proposed scheme for different STATCOM operating conditions. [ABSTRACT FROM AUTHOR]

In order to increase the power transfer and providing the optimum utilisation of the power system capability, application of flexible alternating current transmission system (FACTS) devices technology, such as static synchronous compensator (STATCOM), has been attracted, in recent years. However, the STATCOM changes the voltage and current of the power system that disturb the operation of the impedance‐based synchronous generator loss of excitation (LOE) protection. Then, this study proposes a new flux‐based LOE protection method, in the presence of STATCOM, that is based on the local variation of the flux linkage of the generator available at the location of relay. The mentioned relay is independent of other generator protection relays without any coordination. In order to show the satisfying operation of the proposed method, some simulations have been carried out in the Matlab/Simulink software. A single‐machine infinite bus and a three‐machine infinite bus systems have been used in simulations. The results show that the presence of STATCOM has no important effect on the performance of proposed relay opposite to a negative offset relay with two protective zones (the widely used impedance method) which is affected by STATCOM operation. [ABSTRACT FROM AUTHOR]

Hydro‐Québec's electrical transmission system is an extensive, international grid located in Québec, Canada with extensions into the northeastern United States of America. For large power systems such as this, one of the major issues is to maintain the steady‐state performance of the network. From this point of view, flexible AC transmission system (FACTS) devices could be effective tools to improve power system security by reducing the power flow on overloaded lines, which in turn would result in an increased loadability of the power system, reduced transmission line losses, improved stability and security and, ultimately, a more energy‐efficient transmission system. Therefore in this study, the authors will present the effects of different types of FACTS devices on the performance of Hydro‐Québec's power system. The optimal locations and rating of these FACTS controllers will be determined with a view to improving network security using an optimisation algorithm based on a genetic algorithm. The effects of six different FACTS devices including static VAR compensator (SVC), thyristor‐controlled series capacitor (TCSC), thyristor‐controlled voltage regulator (TCVR), thyristor‐controlled phase‐shifting transformer (TCPST), unified power flow controller (UPFC) and static synchronous compensator (STATCOM) with energy storage are compared. Using the presented results, the effects of different types of FACTS devices on the Hydro‐Québec network will be analysed and compared with those of a STATCOM equipped with energy storage from the viewpoints of static loadability and losses. [ABSTRACT FROM AUTHOR]