This paper presents a wavelet-based technique for detection and classification of normal and abnormal conditions that occur on power distribution lines. The proposed technique depends on a sensitive fault detection pa...This paper presents a wavelet-based technique for detection and classification of normal and abnormal conditions that occur on power distribution lines. The proposed technique depends on a sensitive fault detection parameter （denoted DET） calculated from the wavelet multi-resolution decomposition of the three phase currents only. This parameter is fast and sensitive to any small changes in the current signal since it uses the square of the first and second details of the decomposed signals. The simulation results of this study clearly show that the proposed technique can be successfully used to detect and classify not only low-current faults that could not be detected by conventional overcurrent relays but also normal transients like load switching and inrush currents.展开更多
The protection of distribution networks is facing new challenges from an increasing amount of DG （distributed generation）. Even though current technology provides satisfactory solutions to manage this new situation,...The protection of distribution networks is facing new challenges from an increasing amount of DG （distributed generation）. Even though current technology provides satisfactory solutions to manage this new situation, LOM （loss-of-mains protection） is still considered problematic. The solution proposed in this paper focuses on the use of a line differential protection relay. It inherently contains a suitable communication channel and provides absolutely selective protection for the feeder. Furthermore, it prevents the feeder relays from false tripping for faults on the neighboring feeder. The present trend in protection communication points towards the use of fiber optics. For line differential protection, this means a fast and high-capacity communication link which enables the implementation of many advanced protection functions. In addition, a solid foundation for such a communication link is offered by the new IEC 61850 standard and Ethernet technologies. The basic functionality of the line differential protection enables the operation of both the feeder protection and the DG protection for any fault on the feeder. Furthermore, basic LOM protection methods can be applied as backup protection for failures on the communication link.展开更多
Based on the analysis of a specific relay model and an HVAC （high voltage alternating current） cable system, a detailed approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to cr...Based on the analysis of a specific relay model and an HVAC （high voltage alternating current） cable system, a detailed approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to create complex and accurate relay models derived from the original algorithms. Relay models can be applied with various systems, allowing to obtain the most optimal configuration of the protective relaying. The present paper describes modelling methodology on the basis of Siemens SIPROTEC 4 7SD522/610. Relay model was verified experimentally with its real equivalent by both EMTP-simulated and real world generated current signals connected to the relay.展开更多
文摘This paper presents a wavelet-based technique for detection and classification of normal and abnormal conditions that occur on power distribution lines. The proposed technique depends on a sensitive fault detection parameter （denoted DET） calculated from the wavelet multi-resolution decomposition of the three phase currents only. This parameter is fast and sensitive to any small changes in the current signal since it uses the square of the first and second details of the decomposed signals. The simulation results of this study clearly show that the proposed technique can be successfully used to detect and classify not only low-current faults that could not be detected by conventional overcurrent relays but also normal transients like load switching and inrush currents.
文摘The protection of distribution networks is facing new challenges from an increasing amount of DG （distributed generation）. Even though current technology provides satisfactory solutions to manage this new situation, LOM （loss-of-mains protection） is still considered problematic. The solution proposed in this paper focuses on the use of a line differential protection relay. It inherently contains a suitable communication channel and provides absolutely selective protection for the feeder. Furthermore, it prevents the feeder relays from false tripping for faults on the neighboring feeder. The present trend in protection communication points towards the use of fiber optics. For line differential protection, this means a fast and high-capacity communication link which enables the implementation of many advanced protection functions. In addition, a solid foundation for such a communication link is offered by the new IEC 61850 standard and Ethernet technologies. The basic functionality of the line differential protection enables the operation of both the feeder protection and the DG protection for any fault on the feeder. Furthermore, basic LOM protection methods can be applied as backup protection for failures on the communication link.
文摘Based on the analysis of a specific relay model and an HVAC （high voltage alternating current） cable system, a detailed approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to create complex and accurate relay models derived from the original algorithms. Relay models can be applied with various systems, allowing to obtain the most optimal configuration of the protective relaying. The present paper describes modelling methodology on the basis of Siemens SIPROTEC 4 7SD522/610. Relay model was verified experimentally with its real equivalent by both EMTP-simulated and real world generated current signals connected to the relay.
