Fault indicator

About: Fault indicator is a research topic. Over the lifetime, 10057 publications have been published within this topic receiving 143482 citations. The topic is also known as: FCI & power line fault indicator.

Fault-Tolerant Operation of Three-Phase Cascaded H-Bridge Converters Using an Auxiliary Module

Abstract: This paper presents a new fault-tolerant solution for cascaded H-bridge (CHB) converters, which generates equal output voltages in both prefault and single fault conditions. To generate a balanced three-phase voltage with the highest amplitude regardless of the fault location and its type, an auxiliary module is employed in series with the CHB converter. The auxiliary module is a two-level voltage-source inverter with a capacitive dc link. The module is brought to the circuit after fault detection and its capacitor is charged by a novel algorithm to the reference value. Then, using the space vector modulation, the inverter's reference space vector is synthesized and the voltage of auxiliary module is kept constant. The validation of the proposed method is confirmed by simulations and experiments on a three-phase five-level CHB converter.

Low Voltage Zones to Support Fault Location in Distribution Systems With Smart Meters

Abstract: This paper proposes to combine the voltage monitoring capability of smart meters with impedance-based fault location methods to provide an efficient fault location approach improving service restoration. The first step of the proposed methodology is to apply an impedance-based method to obtain a rough estimation of fault location. Since the result is an estimated distance to the fault, multiple branches can be indicated due to the typical distribution systems topologies. Therefore, the challenge is: how to recognize the actual fault location? To solve this problem, voltage measurements from smart meters are used to build the low voltage zones (LVZs). The main contributions of the proposed fault location technique are to decrease the multiple estimations associated with impedance-based methods, to propose a systematic approach to build the LVZs, and to explore the presence of smart meters for fault location. The proposed method was tested through intensive and extensive simulations in a real distribution system, proving its efficiency.

Unidirectional Fault Current Limiter: An Efficient Interface Between the Microgrid and Main Network

Abstract: Increased fault current level may exceed the rating of the existing network's equipment and disrupt coordination of overcurrent relays (OCRs). Introduction of new dispersed generation (DG) units in a grid connected microgrid is the main reason for increasing the fault current level. To overcome the above-mentioned problems, fault current limiters (FCLs) can be utilized between the microgrid (downstream) and main grid (upstream). Most FCLs have a bidirectional current limiting function. Whereas in the case of a fault in downstream, it is advised to disable the FCL in order to prevent some problems occurring in the microgrid. Power quality (PQ) and reliability of the microgrid as well as coordination between the upstream and downstream OCRs are affected by the bidirectional FCL in case of fault in downstream. In this paper a unidirectional fault current limiter (UFCL) is proposed to achieve a proper interaction between the upstream and downstream. During the fault condition in the main network, the UFCL acts normally; however, in case of fault occurrence or heavy load startup in downstream, the UFCL is disabled to avoid the aforementioned problems in the microgrid. Several simulations and experiments are carried out to demonstrate the effectiveness of the UFCL.

Differential Power-Based Symmetrical Fault Detection During Power Swing

Abstract: Distance relays are blocked during power swing to ensure reliability of the power system. However, if a fault occurs during a power swing, it should be detected and the unblocking function should be invoked to clear the fault as soon as possible. Due to the symmetric nature of signals during the power swing, symmetrical faults are difficult to be detected. In this paper, a differential power-based fault detection technique is proposed for the detection of symmetrical faults during power swings. The differential power is calculated from the difference in predicted and actual samples of voltage and current. The predicted voltage and current samples are obtained using the autoregression technique. The proposed method is tested for different fault conditions and the results are compared with the available method. The proposed method is found to identify symmetrical faults accurately during slow and fast power swings for different power systems.