Multi-agent coalition formation in power transmission planning

Deregulation and restructuring have become unavoidable trends to the power industry recently in order to increase its efficiency, to reduce operation costs, or to provide customers better services. The once centralized system planning and management must be remodeled to reflect the changes in the market environment. We have proposed and developed a multi-agent based system to assist players, such as, owners of power generation stations, owners of transmission lines, and groups of consumers, in the same market to select partners to form coalitions. The system provides users with a cooperation plan and its associated cost allocation plan for the users to support their decision making process. Bilateral Shapley Value (BSV) was selected as the theoretical foundation to develop the system. The multi-agent system was developed by the combination of IDEAS and Tcl/Tk.published_or_final_versio

Allocation of tie-line costs in power exchange scheduling using amulti-agent approach

After deregulations in power industries, the original boundary lines have been removed and how to support optimal cross-border electricity trade planning has become an important issue. Decentralization, or all market participants have the rights to participate in decision making, is one of the directions. In this paper a decentralized structure is suggested to solve the problem using multi-agent technology. In this structure the information centralization is prevented and each market participant behaves rationally based on local information. Although the market participants make decisions to protect its own benefits, the minimum production and transmission cost of the whole system can be finally reached. This structure is based on the method proposed in another paper by the authors and implemented on computer via a multi-agent system using Java programming language. A demonstration on a 5-area test system shows that the suggested new approach is effective and promising.published_or_final_versio

A decentralized approach for optimal wholesale cross-border trade planning using multi-agent technology

Over the past decade, power industry has been undergoing deregulations to introduce competitions among market participants. Once centralized decision making must now adapt to the new market structure. The optimal cross-border electricity trade planning is an important issue in interconnected power systems under transmission open access. In this paper a decentralized approach is suggested to solve the problem using multi-agent technology. In the new approach rational market participants make decisions based on their own benefits, in the meantime the minimum production and transmission cost of the whole system can be reached without a central coordination except necessary information exchange through media like the Internet. A relevant lemma has been proven. The approach is implemented via a multi-agent system using Java programming language. Computer tests on a 5-area test system show that the suggested new approach is effective and promising.published_or_final_versio

A multi-agent based negotiation support system for cost allocation of cross-border transmission

Regulation and protection have been the major issues to prevent the consumers from enjoying good quality of service (QoS) at reasonable prices, for example, electricity and long distance call service. Deregulation in such industries started in early 1970s and have achieved significant results in, for example, telecommunication industry. The deregulation in telecommunication was mainly focused on reducing the market power to add more competition to reduce the price and to improve QoS. Similarly, the power industry in several countries also underwent regulation. The power industry used to be protected and regulated. Consumers were forced to buy electricity from particular suppliers and suffered high prices and low QoS. After deregulation, the original boundary lines have been removed and consumers have more alternatives. How to support optimal planning of cross-border electricity trade has become an important issue since then. Decentralization, or participants have the rights to participate in decision making, is one of the directions of deregulation. In this paper a decentralized structure is suggested to solve the problem by using multi-agent technology to create autonomy for each participant. In such structure the centralization of information transmission or decision making is prevented. Each participant behaves rationally to search for best benefit or payoff through the information she or he owns or through information exchange with other participants. Although all the market participants make decisions to protect their own benefits, the optimal solution (total costs) of the whole system can be achieved finally. This structure is based on the method proposed in [5] and implementation, which a multiagent system called Multi-Agent System for Cross-Border Trade (MASCBT), was done by using Java programming language. A demonstration on a 5-area test system shows that the suggested new approach is effective and promising.published_or_final_versio

An Ac Power Flow Based Sensitivity Method For The Fast Calculation Of Available Transfer Capability

In the context of electricity market, available transfer capability (ATC) is an important indicator of the further usable amount of transmission capacity for commercial trading. It is very meaningful and useful to quickly estimate the effect of any operation parameters perturbation on the ATC value, once a transfer capability value has been given. This paper presents a model for calculating the first order sensitivity of ATC with respect to the variation of any parameters. Combining with continuation power flow (CPF) method, the new ATC can be estimated very fast with first order accuracy. The perturbation parameters include the real injection of bus, regulated voltage of generator bus, and other simultaneous transfer. These sensitivity coefficients can be quickly calculated, and be verified with CPF method. Test results on IEEE 30 bus system shows the efficiency and rapidness of the proposed method. 在電力市場環境下 ,可用輸電能力 (ATC)是反映輸電設備可用于能量交易的剩余容量的重要指標。ATC一旦確定后 ,快速估計出系統參數變化對輸電能力的影響具有很大的實際應用價值。文中首先基于連續潮流方法 ,考慮輸電支路的過負荷約束、發電機有功及無功出力約束和節點電壓約束 ,計算出ATC的值 ;然后推導出ATC對多種運行參數攝動的一階靈敏度計算模型 ,運行參數包括節點負荷功率、發電節點端電壓以及給定的能量交易 ,這些靈敏度系數能夠很快地計算 ;最后 ,使用了IEEE 30節點系統的算例來驗證文中所提出的方法的有效性和快速性。link_to_OA_fulltex

運用動態相量法對電力電子裝置建模與仿真初探

In order to present accurate and simple models for the power system components including electronic converters, such as FACTS devices, a new method based on dynamic phasors is proposed. Dynamic phasors are based on time-varying Fourier coefficient series. By truncating the unimportant higher order Fourier coefficients and keeping only those significant series, the dynamic phasors model can catch the dynamic behavior of the original detailed model. Dynamic phasors present a new point of view for FACTS devices modeling. In particular, two typical examples and their simulation results are presented to show the effectiveness of this method. 隨著靈活交流輸電系統 ( FACTS)元件在電力系統中的廣泛應用 ,為適應針對包含電力電子器件的設備建立簡單而又較準確的數學模型的需要 ,文中提出一種基于時變傅里葉級數的動態相量建模方法 ,可以適用于包含電力電子器件的元件建模。該方法通過忽略系統狀態變量對應的傅里葉級數中那些不重要的項而對原系統進行簡化 ,建模過程中保留可以反映模型本身特性的主要級數項 ,然后由這些保留項構成動態相量模型的狀態變量。經過和詳細時域模型仿真計算結果的比較 ,證明動態相量模型是準確的 ,并且可以大量節省計算時間link_to_subscribed_fulltex

A literature survey on allocations of transmission fixed costs

In the context of competitive electricity markets, transmission fixed costs should be fairly allocated to transmission users. A reasonable allocation method could lead to efficient utilizations of existing transmission facilities and, at the same time, provide economic signals for guiding future generation planning and load sitting. In this paper, a comprehensive literature survey is made on available methods of transmission fixed cost allocations. The review is conducted from several different aspects including: costs to be allocated, entities to pay the costs, system states to be based, cost allocations of unused capacities, pricing of counter flow and that of reactive power, and allocation principles and methods. In addition, the characteristics of each method are analyzed and compared with those of the others. This project is jointly supported by National Key Basic Research Special Fund of China (No. G1998020301), a Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP), China (No. 2000033530) and a Seed Funding Project from the University of Hong Kong

The Hydration Structure at Yttria-Stabilized Cubic Zirconia (110)-Water Interface with Sub-Angstrom Resolution

The interfacial hydration structure of yttria-stabilized cubic zirconia (110) surface in contact with water was determined with ~0.5 Å resolution by high-resolution X-ray reflectivity measurement. The terminal layer shows a reduced electron density compared to the following substrate lattice layers, which indicates there are additional defects generated by metal depletion as well as intrinsic oxygen vacancies, both of which are apparently filled by water species. Above this top surface layer, two additional adsorbed layers are observed forming a characteristic interfacial hydration structure. The first adsorbed layer shows abnormally high density as pure water and likely includes metal species, whereas the second layer consists of pure water. The observed interfacial hydration structure seems responsible for local equilibration of the defective surface in water and eventually regulating the long-term degradation processes. The multitude of water interactions with the zirconia surface results in the complex but highly ordered interfacial structure constituting the reaction front.ope

Use of Bayesian networks to dissect the complexity of genetic disease: application to the Genetic Analysis Workshop 17 simulated data

Complex diseases are often the downstream event of a number of risk factors, including both environmental and genetic variables. To better understand the mechanism of disease onset, it is of great interest to systematically investigate the crosstalk among various risk factors. Bayesian networks provide an intuitive graphical interface that captures not only the association but also the conditional independence and dependence structures among the variables, resulting in sparser relationships between risk factors and the disease phenotype than traditional correlation-based methods. In this paper, we apply a Bayesian network to dissect the complex regulatory relationships among disease traits and various risk factors for the Genetic Analysis Workshop 17 simulated data. We use the Bayesian network as a tool for the risk prediction of disease outcome