The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
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...
Microgrid technologies are highly developed in low voltage networks, improving the power supply reliability and energy efficiency. Therefore, in this paper, the concept, including the configuration, principle and operation of microgrid, will be specified, comparing the microgrid with the prior distributed generation. Additionally, in order to justify the feasibility, the economical benefit analysis...
The paper proposes voltage quality service, and makes comprehensive evaluation to sag energy indices to arrive at a quantitative description, then makes differential pricing of voltage quality service combined with market-oriented theory. It puts forward zonal pricing model of voltage quality service based on sag energy indices, as the foundation of comprehensive assessment of power quality and price...
How to compare the wind power generation and traditional power generation in aspect of capacity is essential of power system expansion. The capacity credit is a convenient and effective way to compare these two different types of power generation. Unfortunately, the definition of capacity credit of wind farms is not clear and generally acknowledged. In this paper, a more clear definition of wind farms'...
In electricity markets, the network is expected to transfer more power to promote profit, but the transfer capability will be affected by uncertainties. In order to quantify the probability and consequence of these uncertainties, the theory of risk is proposed to assess the available transfer capability (ATC). The means clustering method is used to layer the ATC values considering the uncertainties...
Cooperative game theory is firstly introduced into the comprehensive assessment of power quality, and a new model for combination evaluation of power quality is established based on cooperative game. The model takes into account the advantages of 4 kinds of single assessment method. By calculating the characteristic function values of various combinations to get the Shapley value of each assessment...
This paper puts forward an approach that applies active margin, sensitivity index, and N-1, N-2-voltage scanning of the network to search the voltage weak areas, based on the mechanism analysis of the voltage instability and collapse. The installation locations of under-voltage load shedding devices are determined through the voltage weak areas. On this basis, a setting method based on voltage-reactive...
In recent years, consumers of power energy pay more and more attentions on power supply quality, they demand high level supply quality. Therefore, the cost of power quality becomes a main issue to utility engineers when they consider power quality problems. For many industry customers, the main components of power quality costs are short interruption, voltage dips and harmonic costs. The data used...
With the development of electricity demand side market, large consumers have more electricity purchase choices, in the same time have to face the risk of electricity price fluctuation on different markets. In order to measure and hedge the risk reasonably, this paper introduces information entropy as the measure to risk in electricity purchase, by aid of fuzzy optimization, linear membership function...
Establishing an effective performance evaluation method and market driven incentive mechanism is an important subject that the electric power utilities are currently facing with. By aid of Data Envelopment Analysis (DEA) method which is widely used in other industries' performance evaluation, three DEA based models are proposed to evaluate electricity distribution utilities' performances, the relative...
With the increasing expansion of AC/DC transmission system scale, the research on available transfer capability (ATC) for AC/DC transmission systems has important academic and practical significances to AC/DC transmission system planning, operation and reliability evaluation. However, most of the present researches on the ATC calculation are only suitable for AC transmission system, few is about the...
In this paper probabilistic estimation of PCC loss is approached in distribution systems. For the difficulty of directly solving the impedances of the star-connected equivalent model, a port-based model is adopted for voltage magnitude calculation under four fault types (TPF, SLGF, LLF and DLGF). The specific energy (SE) function is used to evaluate voltage sags involving the voltage magnitude and...
Expanding the extra high voltage AC/DC hybrid transmission system and improving the transfer capability of the network are the primary tasks of the power network in China. With the increasing expansion of AC/DC transmission system scale, the super large scale hybrid network has taken shape in china, then the systematic research on ATC calculation model and algorithm for AC/DC systems is urgently needed...
The reliability of electricity supply is required by users increasingly, and whether to invest the reliability and voltage quality has been a point of contention. Thus, the assessment of voltage sag becomes acute. In this paper, the acceptable indices considering system performance and user characteristics are proposed for comprehensive assessment of voltage sag, including the reliability of the system...
The integration of a large number of wind farms will have a significant impact on the reliability performance of the electric generation and transmission systems. In this paper, an adequacy evaluation model of wind power integration in power system based on the sequential Monte-Carlo simulation approach is presented. This model is applied to simulate power system including wind power generation. Depth...
Focusing on the passive network, this paper analyzes the discrete mathematical model and its control strategy of the passive terminal of the VSC-HVDC system on the basis of the alpha-beta frame of axes. The method of the functioning-fuzzy-subset inference is introduced into automatic regulation of the proportional integral (PI) parameters. Based on the digital signal processor (DSP), the fuzzy PI...
In this paper, the equivalent model of a local HVDC transmission system is set up based on Real-Time Digital Simulator (RTDS). A realistic DC line fault on the pole 2 of the HVDC project is simulated successfully by use of the RTDS model connected with actual physical control and protection devices. And then, a complete evaluation theory of simulation errors is proposed. In the theory, residuals similarity...
Optimal generators start-up strategy in the restorative control of a power system following a blackout is a complex, multi-stage decision optimization problem. A novel solution strategy involving the corresponding model and approach to this problem is presented in this paper. The aim of the method is to maximize the total MWh load served over a restoration period whilst considering the corresponding...
Energy storage system is an all-important part in photovoltaic. A new bidirectional DC-AC-DC converter for supercapacitor energy storage system in photovoltaic generation is put forward. In the beginning, some experiments on super capacitor have been performed, which shows super capacitor has good performance in quick charge and discharge. And mathematical model of the dual full-bridge bidirectional...
A nonlinear control strategy based on Lyapunov stability theory is proposed to satisfy stability requirements under the external interference of the uncertainty condition. Due to the nonlinear of the DC voltage differential equation for VSC-HVDC, the control of DC voltage is transformed to the control of the q-axis component of AC current fundamental component. Suitable Lyapunov functions are adopted...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.