Advanced Materials Research Vols. 614-615

Abstract: The fault detection and location technology for the neutral non-effectively grounded system is one of the power-system research areas over the years. This paper describes a practical method for 10kV overhead line fault detection and location by using a real-time online wave recording device. By the proposed method, the run-time health state of the distribution overhead lines can also be monitored easily.

Abstract: The influences of the position of the primary conductor to the mutual inductance of a test Rogowski coil were studied. The test results show that the deviation of the mutual inductances can not be neglected. Manufacturing variations affect the mutual inductance much and make the coils have bad interchangeability. A potentiometer is suggested to be placed in the coil to provide a passive compensation, enabling coil manufacturers to produce coils with uniform performance increasing interchangeability while reducing manufacturing complexity. The error analysis shows that the coil with potentiometer has very good performance.

Abstract: Doubly fed induction generator (DFIG) is receiving more attention nowadays due to growing power demand and environmental concerns. In this paper, five main issues of the DFIG associating with the grid-connection, low voltage ride-through (LVRT), maximum power point tracking (MPPT) control strategy, operation in unbalanced voltage condition, contribution to frequency regulation of grid and influence on power system stability are discussed.

Abstract: A microgrid is composed of multiple distributed generations (DGs).The amplifier and directions of micro-grid power are quite stochastic with the existence of the DGs. It results in great challenges on the adaptability and coordinate issue of protection. The mathematical and simulation models of photovoltaic, AWTG (asynchronous wind turbine generations), DEG (diesel engine generation) and energy storage are established and a typical microgrid containing multiple DGs is also introduced in this paper. It is demonstrated that the transient behavior of microgrid during fault depends mainly on the penetration level of different type of DGs. The simulation results verified that the transient characteristics of fault can provide theoretical basis for the protection of microgrid.

Abstract: Along with the increase of need for high reliability of the power system security, it is important to build up a distribution fault analysis network and processing system, which can provide decision-making help for dispatching personnel. This paper introduced framework of the distribution network fault analysis and processing system, and analyze the fault location, isolation, generation and evaluation of power supply reconfiguration strategy. Tree model and Heuristic search were used for fault location and power supply route switching strategy.

Abstract: With the rapid development of power network automation, the detection of the default single-phase grounding fault line in small current neutral grounding system has became a hot spot in research of power network system. Generally, power network neutral point is not grounded or grounded through arc-suppression coil grounding. When single phase grounding fault occurs, the power network system is named as small current grounding system since the grounding short-circuit is small due to a low-impedance short circuit.

Abstract: A microgrid model with distributed generation including small hydropower source and wind generation source is presented in this paper. The corresponding control strategies for this microgrid are developed. Simulation experiments on island operation mode using Matlab/Simulink software program have been conducted. The simulation results show that the microgrid can operate stably and reliably for load power supply.

Abstract: The paper studied the outside attachment of fibre optical current transformer in smart GIS substation innovation projects. Based on Ampere circuital theorem, sensing optical fibre can be wrapped around the flange at the bottom of the GIS bushing without modification damage on GIS components and long time power cut. The experiment result proved the accuracy and feasibility of this new application. Furthermore, kinds of electronic transformers are compared with fibre optical current transformer, and the analysis gives a conclusion that fibre optical current transformer could be the optimization of system design in smart substation innovation projects.

Abstract: The scheme of intelligent Building based on distributed generation and micro-grid is presented in this paper. There are five parts in the scheme: distributed generation, storage device, charge-discharge device of EV, micro-grid control and energy management system, smart home system. The scheme of the intelligent building in this paper has been realized in displayed project of intelligent community in china. The feasibility of establishing a micro grid system at the branch of power grid is analyzed after evaluating the performance of the micro grid system on saving power, reducing cost in transmit line, and increasing the security. Due to the analysis, this micro system has good performance in these aspects and has a great future in the power grid.

Abstract: Based on the summarization of domestic and foreign experience, the computational method of spacer configuration was developed in order to depress sub-span oscillation principally. The requirements of the reverse recovery characteristics were considered. The computer-aided calculation procedures were programmed. The finite element analysis model of sub-span oscillation for cable-spacer system was established. The inherence modal and amplitude for sub-span oscillation of bundled transmission lines were calculated by using numerical simulation method. The dynamic configurations were analyzed by using the parameters of the cable and spacer obtained from vibration testing.