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The main goal of this paper is to present a new methodology for the estimation of magnitudes of disturbances (EMD). This methodology can be utilized in the adaptive Low Frequency Demand Control schemes in the next generation of distribution and transmission networks. In the focus of this paper will be distribution networks, consisting of conventional consumers and mixed renewable energy sources. The...
In power system stability research, the coordinated control between PSS and FACTS is an important problem. The usually method is to apply genetic algorithm (GA) to optimize the parameters of them. The traditional GA has the merits of parallel algorithm, strong ability of global searching and sample programming. However, its hill-climbing ability is weak, and easily be convergence earier. Tabu search...
The paper presents an ontology model, developed with knowledge based editor, Protigi 3.3.1, for wind turbines' condition monitoring. The ontology model proposed by the authors, describes the wind turbine components, developed a knowledge base, and can be used as the basis of fault detection and diagnosis system to reduce cost per kWh of generation. It Includes sensing specifications, according to...
In this paper the differential evolution (DE) algorithm is used to solve the substation location optimization problem for a distribution network. To improve the capability of the DE algorithm, the dynamic parameter adjustment strategy is used to guarantee the multiplicity of colony in the initial computation period and enhance the optimization speed of the algorithm in the later period. Using the...
Installing subsection switches on distribution network feeders is an effective measure to improve system reliability. In this paper, based on value engineering, a new method is presented to determine optimal subsection scheme. By application of value engineering theory, a new objective function is constructed. The new objective function, based on cost-benefit analysis, is constructed by reference...
In order to analyze the quantified relationship between network time-delay and generators extra power output in NCS (networked control system), a NCS quantizer was designed by researching DTC-SVPWM (direct torque control-space vector pulse width modulation) of PMSM (permanent magnet synchronous motor) on a railway ferry. The paper deduced time delay-power association equation which was induced by...
Generation plant efficiency is an important measure for evaluating the operating behavior of a power plant, and hence an issue of extensive concern with generation companies. On the other hand, in the deregulated electricity market environment, the change of generation efficiency before and after the restructuring is a very important index for evaluating, at least to some extent, if the restructuring...
A good black-start scheme is important and necessary to resume power supply fast and efficiently after black out, and how to choose black-start power is the first thing to consider in the scheme. In this paper, the advantages of VSC-HVDC as black start power are analyzed with contrast to traditional black start power. The ability of VSC-HVDC to soft energize major power system equipment is proved...
The first 1000 kV ultra high voltage (UHV) AC transmission line, connecting central China GridGrid (CCG) and north China Grid (NCG), is being constructed in China. It is necessary and important to analyze the stability of the system with the first 1000 kV UHV AC line. Some new challenges and problems would be found and need a theoretical explain. In this paper, the new instable problems caused by...
An asynchronous parallel method based on equivalence is proposed for transient stability simulation of power system. In the method, the system is partitioned into several interconnected subsystems by geographical location, and the subsystems are equivalent each other at each integration step. Each subsystem utilizes equivalent information from other subsystems to calculate independently. At each integration...
Sites and capacities of substation is one of the key issues for distribution system planning, with the influences of load reliability and network structure. Now days, more influences of substation on society and environment have been concerned by people, and substation planning must be carried out according to the corresponding factors, besides economic cost. This paper presents a new approach for...
This paper proposed an adaptive current directional protection algorithm to meet the variation of the distribution network structure and fault current of the distribution network while DG being connected. The adaptive protection refers to the ability of the protection system to automatically alter its operating parameters to maintain optimal performance in response to changing network conditions....
The fact of a dominant resonance frequency existed in the transient process of short-circuit fault is discovered by analyzing transient characteristics of single-phase earthed fault. At this frequency, the magnitude of zero modal current in faulty feeder is much larger than that in healthy feeder, and their phase is approximately opposite. Dominant transient frequency(DTF) zero modal current in faulty...
In this paper, the control strategy of transformer coupling three phase bridge type solid state fault current limiter (TC-SSFCL) is presented. It is validated in an experimental system. It's proved that the control strategy ensures TC-SSFCL has excellent control performance and current-limiting effectiveness in its normal startup, operation and current-limiting conditions. Issues faced by TC-SSFCL...
In order to reduce the tremendous loss brought about by the overwhelming nature disasters on power supply system, the establishment of a certain amount of distributed generation systems at different level load nodes is taken into account in this paper. A multi-objective mathematical model considering construction investment, network loss as well as network deferred cost is proposed, and a type of...
Anti-islanding protection of power disturbing method for a two-stage photovoltaic grid-connected inverter is designed in this paper. There is little coupling between the input and output power of the inverter as the dc-dc and dc-ac conversion is independent from each other. Step change of voltage across the dc-link filtering capacitor results in a change of stored energy of the capacitor and consequent...
Stability problems of DC Distributed Power System (DPS) arise with the widely use of tightly regulated power modules including: (i) negative impedance characteristic in small-signal sense of constant power load, (ii) the interaction among the power converters. The concept of impedance specifications for a stable DPS was introduced and explained. Electric Double-Layer Capacitor (EDLC) has high power...
The traditional energy structure of our country is single and the environmental pollution is serious. To a certain extent, it impeded the sustainable economic and social development of China. With the energy problems increasing seriousness, distributed generation growing is growing a wide range of applications for the merits of small investment, environmental protection, clean, reliable power supply...
The Optimal sizing and placement of distributed generators has received considerable attention from researchers recently. This paper presents an extensive review of the different solution methods found in the literature and is intended as a guide for those interested in the problem or intending to do additional research in the area. The assumptions made and a brief description of the solution methods...
A multi-objective optimal model is proposed that takes into account minimizing the investment cost of DG and the power loss of distribution network, maximizing the static voltage stability margin, and enhancing the reliability of supply. And this model includes an normalized risk area expressing the uncertainty of DG's output. The immune information processing mechanism of immune system is involved...
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