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This work proposes a new method for choosing the best transmission system expansion plan for the highest satisfaction level of the decision maker. The proposed method considers the permissibility and ambiguity of the investment budget (economics) for constructing new transmission lines and the delivery marginal rate (reliability criterion) of the system. This is achieved by modeling the transmission expansion problem as a fuzzy integer programming one. The method solves for the optimal strategy (a reasonable and flexible plan that would not be significantly worsened by any assumed changes in the surrounding situations) using a fuzzy set theory-based branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. When only a very limited size database is available to evaluate probabilistic reliability indices, the proposed technique provides the decision maker with a valuable and practical tool to solve the transmission expansion problem, considering problem uncertainties. Test results on an existing 21-bus system show that the proposed method is suitable for solving the transmission expansion planning problem subject to practical ambiguities.

This paper proposes a new method for choice of the best transmission system expansion plan on the side of highest satisfaction level of decision maker using fuzzy integer programming. The proposed method considers the permissibility and ambiguity of the investment budget (economics) for constructing the new transmission lines and the delivery marginal rate (reliability criteria) of the system by mode ling the transmission expansion problem as a fuzzy integer programming one. It solves for the optimal strategy (reasonable as well as flexible) using a fuzzy set theory-based on branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. Under no or only a very small database for the evaluation of reliability indices, the proposed technique provides the decision maker with a valuable and practical tool to solve the transmission expansion problem considering problem uncertainties. Test results on the 63-bus test system show that the proposed method is practical and efficiently applicable to the transmission expansion planning.

This paper presents a new method for making a choice of the best line for transmission system expansion planning on the side of the highest reliability level of transmission system. Conventional methodologies for transmission system expansion planning have been mainly focused on economics, which is minimization ofconstruction cost. However, quantitative evaluation of transmission system reliability is important because successful operation and planning of an electric power system under the deregulated electricity market depends on transmission system reliability management. Therefore, it is expected that the development of methodology in order to choice best lines on side ofthe highest transmission system reliability level considering uncertainties of equipments of transmission system is useful in future. The characteristics and effectiveness of the proposed methodology are illustrated by the case study using a MRBTS.

This paper proposes a practical method for transmission expansion planning. This method suggests the optimization grid planning by integer programming using branch and bound method, which utilizes a network flow approach and the maximum flow-minimum cut set theorem to minimize investment budget of transmission line construction and subject to deterministic criterion using a program Cmexp. For. The timing priority of new line construction is determined on the comparison of probabilistic reliability indices of each new system using TRELSS 6.2 program. The new power system is verified an operation conditions as like as the power system stability by using a PowerWorld program. The proposed method has been tested on IEEE-MRTS.

This paper proposes a method for choosing the best composite power system expansion plan considering a outage cost assessment. The proposed method minimizes the investment budget (economics) for constructing new generating units and transmission lines as well as outage cost subject to deterministic (demand constraint) and probabilistic reliability criterion (LOLER), while considering the uncertainties of system elements. It models the power system expansion problem as an integer programming one. The method solves for the optimal strategy using a probabilistic theory-based branch and bound method that utilizes a network flow approach and the maximum flow- minimum cut set theorem. Although the proposed method is applied to a simple sample study, the test results demonstrate that the proposed method is suitable for solving the composite power system expansion planning problem subject to practical future uncertainties.

Reliable operation of power system is fundamental to the on-going industry reform. This paper presents the result of marginal power flow evaluation performed on Korean power system using two commercial software packages: Physical and Operational Margins (POM V. 2.2) and probabilistic reliability assessment (PRA V. 3.1), respectively. The case study of Korea power system for year 2006 data shows that these packages are effective in identifying possible weak points and root causes for likely reliability problems. The potential for these software packages is being explored further for assisting system operators with managing Korea power system under real-life setting in the near future.

The importance and conduct of necessary studies on grid reliability evaluation have become increasingly important in recent years due to the number of blackout events occurring throughout the world. Additionally, quantitative evaluation of transmission system reliability is very important in a competitive electricity environment. The reason is that successful operation of an electric power under a deregulated electricity market depends on transmission system reliability management. This paper suggests that the important input parameters of a probabilistic reliability evaluation tool for the KEPCO-system by sensitivity analysis of high reliability level operation. Simultaneously, it also presents sensitivity analysis probabilistic reliability evaluation of practical KEPCO-system long-term transmission system expansion planning (2006-2010). The tool utilized a Transmission Reliability Evaluation for Large-Scale Systems (TRELSS) which was developed by EPRI and Southern Company Services Inc.

The importance and necessity of conducting studies on grid reliability evaluation have been increasingly important in recent years due to the number of black-out events occurring through in the world. Quantity evaluation of transmission system reliability is very important in a competitive electricity environment. The reason is that the successful operation of electric power under a deregulated electricity market depends on transmission system reliability management. Also in Korea it takes places. This paper presents the probabilistic reliability evaluation for 765KV transmission lines in KEPCO grid expansion planning. The Transmission Reliability Evaluation for Large-Scale Systems (TRELSS) Version 6.2, a software package developed by Electric Power Research Institute (EPRI) is utilized in determining probabilistic reliability evaluation indices of KEPCO-system.

The importance and conducting necessity studies on grid reliability evaluation have been increasingly important in recent years due to the number of black-out events occurring through in the world. Quantity evaluation of transmission system reliability is very important in a competitive electricity environment. The reason is that the successful operation of electric power under a deregulated electricity market depends on transmission system reliability management. Also in Korea it takes places. The results of many case studies for the KEPCO system using the Transmission Reliability Evaluation for Large-Scale Systems (TRELSS) Version 6_2, a program developed by EPRI are introduced in this paper. Some sensitivity analysis has been included in case study. This paper suggests that the some important input parameters of the TRELSS can be determined optimally from this sensitivity analysis for high reliability level operation of a system.

This paper illustrates to determinate how much is the reasonable capacity of tie lines in view point of probabilistic reliability in the North East Asia by using the tie line constrained equivalent assisting generator model (TEAG), which has been already developed by authors. A reliability evaluation program, it is named, NEAREL, based on the TEAG model was made. The reliability evaluation results for an interconnection scenario of the actual power systems of three countries in the North East Asia is introduced. The reasonable capacities of the tie line for three countries interconnection scenario for two target years, 2010 and 2020, are suggested from sensitivity analysis

This paper proposes a method for choosing the best composite power system expansion plan considering a probabilistic reliability criterion. The proposed method minimizes the investment budget (economics) for constructing new transmission lines subject to deterministic (demand constraint) and probabilistic reliability criteria (LOLER), while considering the uncertainties of system elements. It models the power system expansion problem as an integer programming one. The method solves for the optimal strategy using a probabilistic theory-based branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. Although the proposed method is applied to a simple sample study, the test results demonstrate that the proposed method is suitable for solving the power system expansion planning problem subject to practical future uncertainties

This paper compares two methods to solve the grid expansion planning using branch and bound algorithm and Ford-Fulkerson algorithm, given future generation and load strategies, and alternative types of lines available, subject to load, reliability and right of way constraints. From the comparisons of results, it proposes the reasonable algorithm that can be applied to an actual grid system. The grid expansion planning problem is formulated not only as a series of zero or one integer programming that is solved by a branch and bound algorithm but also formulated as linear programming by the Ford-Fulkerson algorithm at minimization total cost subject to reliability constraint (load balance). A test study results on a 63-bus test system show that the proposed method is near side practical and efficiently applicable to the medium size grid expansion planning

Reliability and power quality have been increasingly important in recent years due to the number of black-out events occurring through in the world. Quantity evaluation of transmission system reliability is very important in a competitive electricity environment. The reason is that the successful operation of electric power under a deregulated electricity market depends on transmission system reliability management. This paper presents sensitivity analysis of probabilistic reliability evaluation of Korea power system in long-term planning (2005-2010) by using the transmission reliability evaluation for large-scale systems (TRELSS) program. The case studies present the probabilistic reliability evaluation indices of practical Korea power system as applied TRELSS which has determined optimally control input parameters with Korea power system.

A goal of deregulation electric market is to impulse strengthening competition of new choices and economic benefits for utilities under constraints such as system reliability, stability, security and quality etc... The objective of operational issues would be to minimize the total system cost while satisfying all associated system constraints for the long-term generation and transmission expansion planning. This paper presents sensitivity analysis of transmission congestion by probabilistic reliability evaluation for KEPCO system. This paper focuses on transmission lines/transformers capacity constraints to be associated system load levels to impact on probabilistic reliability evaluation indices of bulk system. The sensitivity analysis of results is included in case studies. This paper suggests that the important input parameters can be determined optimally from this sensitivity analysis for high reliability level operation of a system. TRELSS program was used for the assessment tool

This paper discusses the use of fuzzy set theory to deal with the problem of choosing the best transmission system expansion plan (TSEP) considering the permissibility and ambiguity of the investment budget for constructing new transmission lines and the delivery marginal rate of the system (reliability criterion) while only a very limited size database is available to evaluate reliability indices. The optimal strategy is a reasonable and flexible plan that would not be significantly change due to changes in the surrounding situation. This can be seen as solving the TESP problem for the highest satisfaction level of the decision maker. Test results indicate viability and effectiveness of an approach that models the transmission expansion problem considering practical ambiguities as a fuzzy integer programming problem. It uses the branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem

This paper illustrates the case studies of reliability evaluation for interconnecting power systems in the north east Asia by using the tie line constrained equivalent assisting generator model (TEAG), which has been already developed in the second project year. A reliability evaluation program, it is named, NEAREL, based on the TEAG model was made. The reliability evaluation results for the seven interconnection scenarios of the actual power systems of six countries in the north east Asia are introduced and compared. The reasonable capacity of the tie line for three countries interconnection scenario is suggested from sensitivity analysis.

This paper proposes a method for choosing the best composite power system expansion plan considering a probabilistic reliability criterion. The proposed method minimizes the investment budget (economics) for constructing new transmission lines subject to deterministic (demand constraint) and probabilistic reliability criteria (LOLE/sub R/), while considering the uncertainties of system elements. It models the power system expansion problem as an integer programming one. The method solves for the optimal strategy using a probabilistic theory-based branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. The proposed method is applied to the MRBTS and the test results demonstrate that the proposed method is suitable for solving the power system expansion planning problem subject to practical future uncertainties.

This paper proposes a method for determining the construction priority of transmission lines based on probabilistic reliability evaluation. This method suggests the priority for constructing lines from new transmission lines set of optimal solution obtained by the optimal transmission expansion planning. In this study, the optimality is solved by integer programming using branch and bound method, which utilizes a network flow approach and the maximum flow-minimum cut set theorem to minimize investment budget of transmission line construction and subject to deterministic criterion using a program Cmexp.For. The timing priority of new line construction is determined on the comparison of probabilistic reliability indices of each new system using TRELSS 6.2 program. The proposed method has been tested on IEEE-MRTS.

The importance and necessity of conducting studies on grid reliability evaluation have been increasingly important in recent years due to the number of black-out events occurring through in the world. Quantity evaluation of transmission system reliability is very important in a competitive electricity environment. The reason is that the successful operation of electric power under a deregulated electricity market depends on transmission system reliability management. Also in Korea it takes places. This paper presents the key problems of available features and operation modes of the transmission reliability evaluation for large-scale systems (TRELSS) Version 6.2, a program made in EPRI, for assessing reliability indices of a Korea electric power corporation (KEPCO) system as the first step for applying to actual KEPCO system in the near future. The package accesses not only bulk but also buses indices for reliability evaluation of composite powers system. The characteristics of the TRELSS program are illustrated by the case studies using the KEPCO system.

A new approach considering SOx, NOX and CO2 air pollution constraints in the long-term generation mix with multi-criteria is proposed under uncertain circumstances. Specially, CO2 emission of electricity system industry has over thirty percent of total emission quantity in the world. The CO2 emission in coal power plant competitive with nuclear power plant is very severe. The air pollution in coal is requiring LNG or new environmental type generation system (wind power, solar power tidal power et al.) instead of coal power plant, despite the new generation systems ask for very high construction cost. A characteristic feature of the presented approach is what effects is the air pollution constraints in long term best generation mix. The fuzzy linear programming is used for analyzing ambiguity in this study. A characteristic feature of the presented approach is that not only fuzziness in fuel and construction cost, load growth, reliability and air pollutionbut also many constraints of generation mixcan easily be taken into account by using fuzzy linear programming. The proposed method accommodates the operation of pumped-storage generator. The effectiveness of the proposed approach is demonstrated by applying to the best generation mix problem of KEPCO-system, which contains nuclear, coal, LNG, oil and pumped-storage hydro plantin multi-years.

A nodal probabilistic production cost simulation method is described for power system long-term expansion planning considering unavailability and delivery limitation constraints of the transmission system. This new nodal production cost simulation model includes capacity constraints and unavailabilities of generators as well as transmission lines. This simulation methodology comes from the nodal composite power system equivalent load duration curve (CMELDC), based on a new effective load model at load points developed by the authors. The nodal CMELDC can be obtained from convolution integral processing of the outage capacity probability distribution function of the fictitious generator and the original LDC. It is expected that the new simulation model based on the nodal CMELDC proposed here will provide solutions to many problems based on nodal and decentralised operation and control of electric power systems under a competition environment. The nodal CMELDC based on the new model at load points can extend application areas of nodal probabilistic production cost simulation, probabilistic congestion cost assessment, analytical outage cost assessment and nodal reliability evaluation and so on at load points. The characteristics and effectiveness of this new proposed methodology are illustrated by a small system case study using a network flow and enumeration method.