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Traditional automatic bus transfer methods have difficulty in correctly telling whether it is short-circuit fault or incoming line tripping by security and stability control devices which leads to bus voltage losing. It may cause automatic bus transfer device incorrect operation or refusing action, which effects the stable operation of the power system and reliability of power supply. This paper proposes...
Under the existing 3/2 connection mode, the incompletion between the configuration of the protection and transformer leads to the existence of the dead zone. When the fault occurs in the dead zone, line protection and breaker failure protection are generally matched with each other to achieve the complete isolation of the fault. This approach will make the scope of the circuit breaker to expand, and...
Several cases of unusual mal-operation of the current differential protection for transformer, generator and transmission line already in service, due to the adjacent transformer switching-on, have been reported. The complex inrush current, including the magnetizing inrush current and the sympathetic inrush current, is considered to be relevant with this sort of mal-operation. However, the detail...
A stator earth fault protection scheme based on fault current is presented in this paper. It trips out the faulted generator only if the fault current following the breakdown channel exceeds the tolerance capacity of the generator. Otherwise, it will just emit alarm signals. This protection scheme can avoid unnecessary trip-out of large generator, which influences the safe operation of power system,...
Based on the transient circuit model of series compensated line, a new method for identifying the fault location relative to series capacitor (SC) is proposed. Comparing the transient model of series compensated line when fault occurs before the SC and the one when fault occurs after the SC, it is found that the only difference is the value of a model-parameter: it respectively equals 0 and a large...
Wind power gradually occupies important proportion in modern power grid. The influence of wind turbine generator (WTG) for protective relays has been studied in recent years, but a very few papers are presented to study relative influence to primary protection. This paper proposes a detailed analysis for the operating characteristic of transmission line primary protection in power network which are...
This paper presents a fault location procedure for distribution networks, based on the use of wavelet packet analysis of the voltage transients associated with the fault-originated traveling waves. The proposed method just needs the measured voltage transients recorded at the observation point without the need of multi-recording nodes and relevant synchronization. Fault-originated traveling waves...
A novel wide area backup protection based on multi-agent technique for series compensated lines is proposed in this paper. The principle of conventional distance protection could be remained normally, and the operating procedure of relaying devices in adjacent substations would be coordinated by each agent within protected area. The simulation tests of practical series compensation project based on...
This paper proposes a new partition principle based on bus sequence voltage distribution characteristic for wide area protection system. The influence of short lines, multiple fault and high resistance ground faults are analyzed. Information from multiple points within wide area network is supervised by central station of protection system. Then, suspected faulty zone can be detected according to...
In this paper, a novel isolated current-fed DC-DC converter (boost-type) with two input power sources based on multi-transformer structure, which is suitable for fuel cells and super-capacitors hybrid energy system, is proposed and designed. With particular transformer windings connection strategy, the proposed converter can draw power from two different DC sources with lower voltage and deliver it...
Based on power electronic converting current devices which can be controlled quickly, VSC-HVDC system can regulate active power, reactive power, DC voltage, and line voltage flexibly. Different regulation strategies have different influences on the power system stability. A worse regulation strategiy may lead to sharp fluctuation of electrical measurements and longer regulation time, which is harmful...
The characteristics of double-circuit transmission lines protection are expatiated. Main protection principles and protection configuration schemes of real operating double-circuit transmission lines in China are introduced. Based on the summarize of protection schemes and engineering experiences, the analysis of tripping reasons and measures of wrong trip incidents of the double-circuit transmission...
Different stator winding types of multi-branch generator lead to different internal short circuit fault aggregation, and the main protection scheme research must base on this fault aggregation to educe the optimized branch grouping style on neutral side and the main protection configuration principles. The paper analyzed the stator winding type and internal short circuit faults of 250 MW generator...
Ultra-high voltage (UHV) transmission possesses enormous economic benefits and technical superiorities, which is a new subject for China and must be studied emphatically. This paper introduces the actual configuration and parameter of UHV transmission under construction in China and its physical dynamic simulation (PDS) experiment model. According to the structure and operation characteristics of...
Because of the complexity of topology and control strategy, the mid-voltage and large power frequency converter has more failure types and fault feature relatively. Then the correct identification and isolation of its internal faults are very important. Based on the MATLAB/Simulink, this paper established a complete fault simulation model of IGCT series mid-voltage & mid-power three level frequency...
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