This paper puts forward a novel topology of controllable reactor, the structure is based on many small capacity thyristor controlled reactor (TCR) modules and a three-windings transformer connecting to system. The tra...
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This paper puts forward a novel topology of controllable reactor, the structure is based on many small capacity thyristor controlled reactor (TCR) modules and a three-windings transformer connecting to system. The transformer secondary adopts duplex winding structure and each has multi-bank TCR modules being in delta connection. In this topology, the harmonic current injected into the powersystem is very small. It not only possesses all the functions a traditional TCR has, but also has many other merits such as occupying small floor space, generating little loss, easy implement control and protection scheme, and high reliability etc. A 500 kVar industrial prototype is under construction in Langfang, Hebei province of ***. Digital simulation based on EMTDC/PSCAD and field test were carried out to verify the perfect harmonics characteristics of topology proposed
A new load detection method was presented based on its running status of powersystem. The loads are sorted according to their index of capacitive, inductive, and none-linear. The static character of each load was got...
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A novel method is put forward, which the power meter can be read based on compute vision, and the architecture of remote meter auto reading system is designed. Different with the normal automatic meter reading system ...
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It's important to make an accurate PD location in transformers for fault diagnosis and maintenances of powersystems. Theoretically it's possible to locate the PD source by measuring the differences in the arr...
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It's important to make an accurate PD location in transformers for fault diagnosis and maintenances of powersystems. Theoretically it's possible to locate the PD source by measuring the differences in the arrival time at the UHF sensor array. The propagation velocity of EM wave in air is 30 cm/ns, which is extremely fast, so the resolution of the time-delay of UHF signals detected at the UHF sensor array is one of the key points to make an accurate PD location. Here, we propose a mathematical method: cross-correlation-shifting-averaging algorithm that can improve the resolution of the UHF signal's time-delay by increasing the signal to noise ratio and reducing the time dispersion caused by the random nature of PD. The practical processing results of experimental data from our laboratory indicate that the method can increase the time-delay resolution by nano-seconds in some cases, which improve PD location accuracy by tens of centimeters.
This paper presents an identification method based on the iterative Prony to identify transfer function and configure PSS parameters using residue way. The iterative Prony is a very useful method to acquire power syst...
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This paper presents an identification method based on the iterative Prony to identify transfer function and configure PSS parameters using residue way. The iterative Prony is a very useful method to acquire powersystem oscillation modes, by which the system eigenvalue, oscillation frequency, amplitude, damping and relative phase can be directly estimated using the response of given input signals. Considering the influence of input signal on output signal, the iterative Prony can acquire the transfer function of powersystem, then, according to the corresponding residues we conducted coordinated setting of powersystem stabilizer (PSS) by residue method. The simulation results for two testing system examples prove that this proposal method is effective in the powersystem oscillation mode analysis and parameters determination of PSS, can improve eigenvalues of system and can enhance system damping after PSSs whose parameters are optimized by above method are built into powersystem
Based on rough set, this paper use discernibility matrix to reduce the condition attributes. The reduced samples are laid by weighted mean roughness to avoid blindness and redundancy. By this method, model space can b...
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Based on rough set, this paper use discernibility matrix to reduce the condition attributes. The reduced samples are laid by weighted mean roughness to avoid blindness and redundancy. By this method, model space can be compressed greatly and weighted mean roughness is easy to calculate. Weighted mean roughness is used to separate attributes' priority in every lay, which make the diagnosis system had strong tolerant ability. When the electric power grid is fault, the result of diagnosis will be correct by searching every lay with priority level. The correctness and effectiveness are validated by the analysis result of emulation
This paper focuses on the research on the DC bias due to magnetic storm and HVDC. In the paper, we introduce the DC bias problem of Jiangsu Yang-Huai transmit electric system and Southern power Grids, discuss the harm...
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This paper focuses on the research on the DC bias due to magnetic storm and HVDC. In the paper, we introduce the DC bias problem of Jiangsu Yang-Huai transmit electric system and Southern power Grids, discuss the harmful effect of the transformer DC bias and the significance of research, and analyze the compensation, weakening and elimination of transformer bias current. Finally, the problems that should be paid attention to and some corresponding suggestions are proposed
Harmonic pollution and reactive power compensation are the important power quality problems. This paper proposes a combined power filter system consisting of the parallel operation of a hybrid active power filter (HAP...
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Harmonic pollution and reactive power compensation are the important power quality problems. This paper proposes a combined power filter system consisting of the parallel operation of a hybrid active power filter (HAPF) and the passive power filters or capacitors. The HAPF is formed by a single tuned LC filter per phase and a small-rated three-phase active filter, which are directly connected in series. The characteristics of the combined system and the harmonic current detection method using the combination of load current and the mains current are analyzed and simulated. The simulation results show that good filter performance can be obtained by the combined system. Experimental results from a 100 kVA/380 V hardware prototype parallel operation with capacitors are presented to conform the validity and effectiveness of the combined system
The multi-objective fuzzy optimal method based on the fuzzified optimal solutions of single objectives need not list all non-inferior solution sets, which can optimize directly objectives in value area of variables. T...
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The multi-objective fuzzy optimal method based on the fuzzified optimal solutions of single objectives need not list all non-inferior solution sets, which can optimize directly objectives in value area of variables. This method can reflect the interrelation between individual objective optimal solutions and multi-objective optimal solution. On the basis of fundamental principle of multi-objective fuzzy optimization and genetic algorithm, combing with the concept of objective relative subject degree, this paper presents a multi-objective optimization approach for the hydroelectric powersystem with contradictory objectives. The proposal method considers the satisfied degree of various characters and contradictory objectives and seeks an appropriate optimized solution to make each objective optimal as possible considering each objective comprehensively. The simulation results of example show that the fuzzy genetic algorithm is an effective method for multi-objective optimization problem in the cascaded hydroelectric plants
This paper presents a multi-agent and WAN based adaptive coordinated protectionsystem (MAWBACPS). The system utilizes IP intranet to realize real-time wide area information exchange of a powersystem. Multi-agent sys...
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This paper presents a multi-agent and WAN based adaptive coordinated protectionsystem (MAWBACPS). The system utilizes IP intranet to realize real-time wide area information exchange of a powersystem. Multi-agent system's several good qualities to solve distributing problems are used to realize the coordination of the operation settings of protective relays. A new idea of effortful adaptation for powersystemprotection is proposed, and a new method to determine adaptive coordinated relay settings of lines are proposed in this paper. Moreover, the structure, communication mechanism and coordination control strategy of MAWBACPS, and relating agents' design are presented. Experiment results illustrate that MAWBACPS can realize the coordination of protections, enable the back-up relays to use their adaptive settings in most situations, and efficiently improve the security of powersystem
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