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Due to the manifest electromagnetic coupling effect, parallel cables cause couples of problems to its operation safety and management. The present paper describes the questions brought by parallel cables from the following three aspects: influence on parameter asymmetry, influence on induced voltage in metal shield of cables and influence on distance protection. This paper analyzes the parameter asymmetry...
With excellent priorities, Voltage Source Converter based HVDC (VSC-HVDC) will be the promising offset of HVDC transmission technology. This paper presents a protection and fault location method for VSC-HVDC transmission lines using one terminal current data. The proposed method is based on the natural frequency from the reflection process of traveling wave on a distributed parameters transmission...
In order to improve characteristics of pilot protection, a new pilot differential protection based on parameter identification is proposed. In this new approach, the transmission line is dealt as PI model. As we know, the simplified PI model can only match physical lines within limited frequency band, which is defined as suitable frequency band (SFB). In order to apply the new approach, it is important...
Increased integration of wind power makes higher demands on the stability and protection of Power System. Wind farms are connected to power grid through transmission line. When single-phase fault occurs on the line, positive and negative sequence currents are not equal and are much smaller than zero sequence current. Phase selector based on the theory of current- difference sudden-change may mistake...
The distance protection relay is widely used around the world for the protection of transmission and distribution networks and it is especially essential in its application within bulk power systems. The faulted phase and the fault point on the power line must be determined by the relay with great certainty. In this paper, we propose a unique method to enhance the faulted phase selection function...
Series capacitor can enhance transmission capability of power grid and optimize the power flowed to improve the transient stability of power systems. However, they change the magnitudes and the directions of fault voltages and currents in series compensated networks and impact the protection performances. This paper analyses the fault electric quantity characteristics and discusses the operation behaviors...
This paper introduces a method for fault location in a marine power system which uses the voltage and current transient information at a power supply point and the remote point beyond the fault location to estimate the fault position. The proposed algorithm was demonstrated by computer simulation in Matlab with a 6-zone marine power system which has short distribution cables and requires fast and...
This paper proposes an enhanced one-terminal fault-location algorithm in which its salient performance is to combine the advantage of minimal fault data requirement for standard IEEE one-terminal algorithm with the advantage of superior accuracy for two-terminal algorithm. Assuming that voltage phasor at any bus can be easily obtained, and that fault impedance can be treated with resistive characteristic,...
This paper presents a new pilot protection scheme based on fault component integrated impedance (FCII) of transmission line with thyristor controlled series capacitor (TCSC) and controllable shunt reactor (CSR) through the fault analysis of transmission line with TCSC and CSR. The FCII is defined as the ratio of the sum of the fault component voltage phasors across the two terminals in the transmission...
The distribution network will be changed from the single power to the multi-power supplied when DG combined into it. Three-section current protections will no longer be applicable. Therefore, a new protection scheme which is suitable for the distribution network contained DG be proposed, which is that the protections lying on the downstream lines of DG need to have new setting value, and the protections...
To solve the problems of the incorrect operation, the failure action and the low operational percentage on Residual Current Operated Devices (RCDs) in the domestic rural power distribution network, an amount of electric shock signals were demanded to study identifying and extracting method of electrical shock current. In this paper an equivalent circuit model of the human body against electric shock...
Smart grid will bring new opportunities to development of relay protection, new sensor technology is used in smart grid. Simplified algorithm to protect data, reducing data processing time. With the State Grid Corporation of China launched the construction of smart grid, smart grid caused by the characteristics of network reconfiguration, distributed power access technologies such as micro-network...
A novel phase selector is proposed based on the multi-parameter comparison of fault components. Each of three phases is used as the reference phase in turn to calculate the positive sequence component and the sum of the zero and negative sequence components. The phase difference between the positive sequence component and the sum of the zero and negative sequence components is calculated under three...
This paper presents an algorithm for locating faults on series-compensated transmission lines. The algorithm suits to both single- and double-circuit series-compensated lines. Use of two-end synchronized measurements of currents accomplished by current differential protective relays with additional incorporation of the locally measured three-phase voltage is considered. More superior solution with...
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