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Conventional transmission planning models are subject to constant debate in the context of competitive markets, due to the functional unbundling of transmission sector from generation and distribution sectors and due to the new environment regulations. A value-based transmission planning model is proposed, suitable for an unbundled transmission network service provider having no assets in the generation sector. The model minimizes the long-term transmission investment costs and the expected social costs incurred to its clients, energy producers, and consumers, in the power auctions due to transmission bottlenecks. The uncertainties involved when incorporating short-term market models into long-term planning models are modeled with probabilistic representations for the bid prices, the component availabilities, and the hourly load variations. These features make this model suitable in the new environment paradigm. Generalized Benders decomposition technique with nonsequential Monte Carlo technique is employed to solve the final stochastic mixed-integer optimization model. Case studies are given to illustrate the performance of this model by implementing it in the modified Garver's six-bus test system and the IEEE 24-bus reliability test system for a single planning year. CE Database subject headings: Grid systems; Networks; Investments; Optimization; Electric transmission.

This paper addresses the optimal management of hydropower resources on medium term. The objective is to maximize the expected revenue of a producer, and the decision variables are generation and forward contracts in each period for each scenario. Stochastic linear and nonlinear programming has been used as a framework for modeling and solution. Results are exposited for a Norwegian power producer participating in Nord Pool, the Nordic power exchange. Index Terms--Electricity contracts, hydro scheduling, risk analysis, stochastic processes.

A framework for transmission planning in a deregulated power market environment is discussed. The level of congestion in the network is utilized as the driving signal for the need of network expansion. A compromise between the congestion cost and the investment cost is used to determine the optimal expansion scheme. The long-term network expansion problem is formed as the decoupled combination of: 1) the master problem (minimization of investment costs subject to investment constraints and the Benders cuts generated by the operational problem (power pool) and 2) the operational problem, whose solution provides congestion details and associated multipliers. A proper power-pool model is developed and solved for congestion cost, congestion revenue, and transmission shadow prices. Linear programming is utilized to solve the investment subproblem, while the quadratic programming technique has been used to solve the operational problem. The algorithm has been developed for the complete planning process, which provides the expansion schemes for the planning horizon. The technique has been applied to illustrate the network planning study for a modified IEEE 24-bus test system. Index Terms--Locational marginal prices (LMP), network expansion planning, network congestion, power pool, social cost and benefit, network investment.

Ramp rates of generators are generally specified within elastic range of the strength of the shaft to safeguard the rotor from fatigue. These limits can, however, be exceeded, albeit at the risk of reducing the rotor life. Such effects on the rotor life can be compensated by incorporating appropriate ramping costs. Power demand and power price in deregulated power markets have shown a tendency of sudden wide excursions over short intervals of time. The ability to respond to such fast change in demand and price can be quite rewarding. This provides the motivation to utilize the ramping rates beyond traditional elastic limits. This paper studies the strategic use of ramping rates beyond elastic limits in a power producer's self-dispatch in a power market with price and demand volatility. A set of ramping processes has been developed from ramping-cost versus ramping time relationships to derive the total operation cost including ramping costs for various levels of ramping rates exceeding elastic limits. A thorough theoretical analysis has been conducted for the selection of the optimal ramping process under different conditions. A numerical example is presented to highlight the potential benefits from the optimal use of these ramping processes. It is seen that the benefit from the strategic use of ramp rates beyond elastic limits not only depends on the high price in the power market but also on the initial loading of the generator which limits the capacity available for dispatch. Index Terms--Power dispatch, power market, ramp rates, ramping cost, ramping process.

Performance evaluation of a combined generation and transmission system normally includes the independent outages of generators, transformers and transmission lines. However, substation originated outages due to failure of breakers, transformers and busbars can also have a significant effect on the bulk power system performance indices in terms of outage frequency and duration. The studies described in this paper utilized various substation components such as breakers, busbars and transformers to develop a general-purpose software to assess the reliability of the system. It performs failure modes and effect analysis and provides a concise and orderly description of the various combinations of occurrences within a system that could result in an interruption of supply. Reliability analysis technique using the minimal cut set method has been implemented. In addition the software package is able to define and incorporate 15 types of system configurations in the analysis and at the same time, comprehensive analysis tools such as print, save, sensitivity studies, tutorial guide, etc., are also included. The concept associated with the reliability analysis is illustrated by application to a simple but comprehensive system configuration. Keywords: Substation reliability; Software development; Reliability analysis

One major application of photovoltaic(s) (PV) power has been in remote areas as isolated small power generation for essential electric power. This paper discusses issues in optimizing the use of such stations and presents a procedure to evaluate different PV schemes considering the stochastic natures of the insolation and the load. The reliability measures in terms of loss of load hours (LOLH), the energy loss and the total cost have been used as the indices for evaluation of different schemes. The insolation and the load demand are modeled as stochastic variables using historical data and experimentation respectively. The operation of various stand-alone schemes are simulated for a specific load. Actual commercially available panel and battery sizes with actual costs have been used in the various configurations studied. The long run expected values of the performance indices for various configurations of the solar station have been measured. Comparative analysis of the results show that higher cost not necessarily translates into better performance. The panel size and the battery size have different impacts on the indices of performance, and a proper balance between the two is necessary to optimize the operation of a stand-alone PV scheme. Keywords: Photovoltaic(s) power, Stand-alone scheme, Simulation, Optimization of solar power.

This paper describes the main features of four design modules that form part of the curriculum for the final year power engineering students at the Nanyang Technological University, Singapore. Through the use of these modules, the students gain an insight into the various aspects of power engineering including power electronics and drives - and this will hopefully help them in a better understanding of the practical aspects of power engineering, and therefore make them better engineers in the power industry. The four modules described are Generating Capacity Expansion Planning, Rectifier and DC Motor Control, Power Systems Operations Planning, and Security Enhancement using Optimal Power Flow. Keywords: power system design, power engineering education, undergraduate curriculum, power system planning.

The electric utility's interest in electric vehicles lies in the anticipated/expected benefits beyond the simple increase in energy sales. It is expected that the EV load will be contained within system off-peak hours without affecting the peak demand, thus increasing the sale of low cost electricity. However, the impact of electric vehicle charging on the energy and power demand is determined not only by the number of EV's in use and their usage pattern, but also by the number of EV's being charged at an instant and the charging profile of the battery module. The daily energy consumption by an EV will be limited by the range/cycle and the charging time, while its impact on the system demand will depend on the hour and pattern of charging. The case studies in this paper have revealed several important issues regarding the impacts EV load may have on utility distribution systems. Firstly, it is not adequate to have only sufficient generation capacity during off-peak hours to assure a system's ability to absorb EV loads without adverse effects. The constraints at the distribution level must be studied properly. Secondly, a sizable EV load can introduce a new peak in the early off-peak period. It may have scheduling implications, and completely throw any load management programs off balance. Thirdly, at the present state of EV technology, including those of battery modules and chargers, a typical distribution system may not be able to supply EV loads beyond 20% penetration level. This constraint is created by the long (up to 12 hours) charging cycle of batteries.

As deregulation of power industry is becoming a reality, there has been an intense interest in the strategic bidding for suppliers to optimize their benefits. The benefit gained by a supplier is related not only to its energy-price bid curve but also to its submitted operational parameters such as minimum output, etc. This is especially so when market size is limited because of a limited number of competitors in the market itself or due to the transmission capacity constraints. This paper addresses the study of strategic bidding for minimum output in a deregulated environment. The impact of minimum output bids on the market result is analyzed. A criterion with regard to minimum output bid to assess the outcome of competition among suppliers is derived. The method to optimize the benefit from a supplier's viewpoint by adjusting the bids for the minimum output and price is proposed. It is shown that an individual supplier can optimize its own benefit by fine-tuning its minimum output and price when there are only a few suppliers dominating the market. A fairly thorough theoretical analysis of the bidding for minimum output is illustrated with a numerical example. Index Terms--Minimum output, power market, strategic bidding.