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Subharmonic resonance occurrence in power system more frequently. This paper used mathematical analysis method for solving the nonlinear differential equations based on the system equivalent diagram, and deduced the mathematical expression of the subharmonic resonance, derived the relevant affective factors of subharmonic resonance overvoltage amplitude, and analyzed the influence of all relevant...
This paper mainly study on the coordinated voltage control scheme with model predictive control (MPC). As the decomposition-coordination technology and the auxiliary problem principle is employed into the MPC based voltage control problem, a distributed voltage control model and structure can be obtained, and the global centralized optimization problem is decomposed into some sub-problems. All sub-problems...
This paper presents an accurate track modeling for fault current on dc railways based on MATLAB/Simulink. With the introduction of skin effect of short-circuit current, the simulation of short-circuit fault based on MATLAB/Simulink is proposed. By comparing and investigating the waveforms of remote short-circuit current with and without skin effect, the paper pointed out the difference between these...
With the continue increases in power system voltage level, more and more complex wiring has resulted in the more frequently occurrence of the subharmonic resonance. To address this issue, this paper deduces the mathematical expression of the subharmonic resonance and uses mathematical analysis method to solve the nonlinear differential equations based on the system equivalent diagram. The relevant...
Dynamic voltage stability analysis is mainly based on the time-domain solution of power system differential and algebraic equations. The modeling of each power element has a great influence on the correctness and complexity of stability analyzing. It is significant to model appropriately for simplifying calculation and drawing out principal contradiction. In this paper, the dynamical mechanism of...
This paper presents a simulation of articulated neutral section insulator in DC Railway System. With the introduction of Beijing subway structure, the special way of the connection of neutral section is proposed. By comparing and investigating the waveforms of locomotive passing neutral section current and starting current, the paper pointed out the difficulty of discrimination between remote short...
This paper presents two comprehensive models of DC subway traction system to simulate the starting-up process using Matlab/simulink. One is DC motor driven, the other is AC motor driven. The model includes substation rectifiers, the track and the different driven subway trains. The objective of the model is to study the short circuit faults and the train starting current. Analysis and conclusion of...
In recent years, with the rapid development of the power electronic technology, various power electronic devices and nonlinear elements, especially of many kinds of rectifier and switcher, are applied widely in power system. Harmonics have produced serious adverse effects in the equipment of power generators and distribution system, and of their control and protection, as well as the users and the...
The emerging smart grid requires more reliable communication technology. This paper presents a coded adaptive BFSK PLC solution for medium voltage power line communication with low SNR and frequency selective attenuation. The measure based powerline channel model in China is given first, then the data transmission system is proposed for MV PLC. Three centre frequencies is used to optimize data transmission,...
In this paper, on the basis of the analysis of power line channel characteristic,we firstly build a power line channel mode. And then, we elaborate the spectrum theory and its main performance indexes. At last, the direct sequence spread spectrum communication system is build by MATLAB/Simulink using the power line channel mode. The simulation results prove that the Spectrum-spread Technology can...
In this thesis, existing instability criterion and its stability indicator τ for autonomous single machine infinite-bus system (SMIB) are firstly given, which reflect convex-concave characteristics of the trajectory inΔω-δ phase-plane. On this basis, it is discussed that there are some problems when the instability criterion of autonomous SMIB system is used in non-autonomous SMIB system. Proceeding...
IEC 61850 based substation automation systems simplify the design, installation and maintenance with significantly reduced cost. Its real-time, security and reliability are of concern and are vital important to the industry. This paper presents the development and application of an established platform for evaluating process bus applications. The evaluation platform consists of a number of GOOSE,...
This paper presents a comprehensive simulation model for sequential tripping in DC traction system based on MATLAB/Simulink. With the introduction of practical operation of DC traction system, the scenario of “Large double end” feeding arrangement is under analysis. Based on this special scenario, the technique of simulation and protection scheme is presented. Moreover, the suggestion of setting value...
In the paper, the complete lightning model for HVDC transmission lines is presented, and the model is divided into five parts: lightning discharging model, insulator string flashover model, arrester model, tower model and conductor/ground wires model. The proposed lightning model was successfully tested in the PSCAD/EMTDC software. And the model is shown to be a potential tool for studying on lightning...
This paper mainly study on the model predictive control (MPC) based method in the emergency voltage control. The coordinated voltage control scheme and the MPC model of voltage control are introduced firstly. Next, the Lagrange decomposition and auxiliary problem principle is employed into the MPC model of voltage control and a distributed MPC based voltage control scheme can be obtained, by which...
In the paper a new method of high resistance fault detection meant for current differential protections of two-terminal transmission lines is presented. The method is based upon calculation of line differential admittance in pre-fault and in faulty conditions. As the ground fault current during high resistance faults is comparable and, sometimes for long transmission lines, even lower than the line...
Due to the fact that wide area information is easily disturbed, lost and distorted, while it is not fully considered in current wide area protection principle, a wide area backup protection algorithm with high fault-tolerance performance is proposed to implement the CSBPS(Centralized Substation Backup Protection System). After the fault-tolerance judgment, The CSBPS can locate the fault equipment...
This paper puts forward a new transformer self-adaptive protection principle. The principle is based on equivalent equation. The principle mainly includes three components: parameter estimation unit, high speed protection unit and fault component protection unit. When there is serious fault in transformer, the high speed protection unit can act quickly. When there is weak fault in transformer, the...
In this paper enhanced differential current protection scheme dedicated for HV transmission lines is described. The adaptive fuzzy relay scheme is proposed that combines strengths of both current and phase comparison protection criteria. The relay stabilization characteristic is adapted on-line depending on the output of the fuzzy reasoning scheme supplied with information from the phase comparison...
If the trip of overload branch may cause cascading tripping in corresponding section, emergency overload control should be executed to ensure the security of the transmission section and maintain its integrality and transmission capacity. A series of improvements against the conventional sensitivity algorithm are proposed, which include the advance of the integrative sensitivity, the use of equal...
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