G. A. Orfanos

Transmission Expansion Planning of Systems With Increasing Wind Power Integration

This paper proposes an efficient approach for probabilistic transmission expansion planning (TEP) that considers load and wind power generation uncertainties. The Benders decomposition algorithm in conjunction with Monte Carlo simulation is used to tackle the proposed probabilistic TEP. An upper bound on total load shedding is introduced in order to obtain network solutions that have an acceptable probability of load curtailment. The proposed approach is applied on Garver six-bus test system and on IEEE 24-bus reliability test system. The effect of contingency analysis, load and mainly wind production uncertainties on network expansion configurations and costs is investigated. It is shown that the method presented can be used effectively to study the effect of increasing wind power integration on TEP of systems with high wind generation uncertainties.

A More Fair Power Flow Based Transmission Cost Allocation Scheme Considering Maximum Line Loading for N-1 Security

This paper proposes an efficient approach to transmission fixed cost allocation in a pool based electricity market that takes into consideration N-1 secure annual system operation. The optimal capacity of a transmission facility is defined as the maximum power flow the facility may face under a contingency situation for a certain system snapshot. In this pricing approach, for each time interval, the largest optimal capacity of a transmission facility is calculated for all N-1 conditions considering a security constrained optimal power flow. Charges for each facility are based on the facility usage of the largest optimal capacity for all time intervals during one or more years. Network usage is determined by generalized distribution factors and three variations of the MW-Mile method for pricing counter-flows are investigated for the proposed cost allocation method. The three proposed pricing methods are applied to the IEEE 24-bus reliability test system and compared with other pricing methods.

European scenario synthesis to be used for electricity transmission network planning

The EU research project IRENE-40 aims at the development of a roadmap for the European and Pan-European transmission networks for the next 40 years (until 2050). In addition to the know-how which technologies can be applied to solve transmission problems in the near and far future, an evaluation of the future generation and load scenarios is necessary. For this purpose five scenarios have been developed: BUSINESS AS USUAL (BAU) - RENEWABLE (RES) - DESERTEC (DES) - CARBON CAPTURE AND STORAGE (CCS) - HIGH EFFICIENCY (EFFICIENCY). In these demand-and generation scenarios the share of renewable, the penetration of Carbon Capture and Storage and the level of electricity demand vary widely. The reasoning behind the choices in the main parameters for these scenarios are discussed. The wide range in some of the major scenario assumptions cause substantially different circumstances for future grid expansion, Especially the share of solar PV and wind in future generation is a crucial parameter influencing the demand for long-distance transmission at a European scale. A comparison is made with some other recent scenario and roadmap studies with a 2050 horizon.

Evaluation of transmission pricing methodologies for pool based electricity markets

This paper presents and analyses several approaches for transmission cost allocation in a centralized pool based electricity market environment that includes composite embedded/marginal transmission pricing mechanisms. The revenue from marginal cost based remuneration (MBR) necessitates supplementary charges; thus it is required to identify the contribution of individual generators and loads to the line flows using tracing methods and implement usage-based transmission pricing methods for allocating the remaining fixed cost. Eight transmission pricing schemes and three tracing methods are being evaluated and applied on Garvers 6-bus system and on IEEE 24-bus reliability test system to illustrate the different results derived among the pricing schemes for each tracing method or among tracing methods for each pricing scheme.

Computer-Assisted Interactive Learning for Teaching Transmission Pricing Methodologies

This paper presents a computer-assisted method to teach and understand transmission pricing techniques. The education method is facilitated by specially designed user-friendly transmission pricing software (TPS). The proposed approach helps students fully understand transmission pricing through the fulfillment of the following educational objectives: 1) use of TPS to solve the transmission pricing problem of a small power system as well as a real-world power system; 2) complete understanding of the mathematics involved and development of software code to reproduce part of the results of TPS; 3) analysis of the results, identification and justification of the differences among three transmission tracing techniques and eight transmission cost allocation methods; and 4) extension of TPS methodologies. These methods have been proven effective in the education of students studying power system economics at the National Technical University of Athens (NTUA), Greece. A full-fledged, robust, comprehensive study of the educational improvements achieved through the use of TPS is provided.

Transmission expansion planning by enhanced differential evolution

The restructuring and deregulation has exposed the transmission planner to new objectives and uncertainties. As a result, new criteria and approaches are needed for transmission expansion planning (TEP) in deregulated electricity markets. This paper proposes a new market-based approach for TEP. An enhanced differential evolution (EDE) model is proposed for the solution of this new market-based TEP problem. The modifications of EDE in comparison to the simple differential evolution method are: 1) the scaling factor F is varied randomly within some range, 2) an auxiliary set is employed to enhance the diversity of the population, 3) the newly generated trial vector is compared with the nearest parent, and 4) the simple feasibility rule is used to treat the constraints. Results from the application of the proposed method on the IEEE 30 bus test system demonstrate the feasibility and practicality of the proposed EDE for the solution of TEP problem.

Methodology for assessing transmission investments in deregulated electricity markets

Transmission system planning in deregulated markets often includes a set of proposed alternative expansion schemes instead of a single optimal network solution. In this paper, a methodology is proposed for the economic evaluation of alternative transmission expansion plans, based on several indices that measure the market performance of the expansion schemes. The proposed methodology can assess in a realistic way both reliability-driven as well as economic-driven transmission expansion projects. In order to demonstrate the proposed methodology, three possible transmission expansion solutions over the IEEE 24-bus reliability test system are compared. The indices introduced are calculated for each scenario scheme and the results are assessed in order to determine the scenario with the best cost-benefit economic performance. This paper derives from the work performed for the IRENE-40 EU research project.

Transmission expansion planning in deregulated electricity markets for increased wind power penetration

In this paper, a model for transmission expansion planning (TEP) in deregulated electricity markets is developed, considering transmission congestion, wind power integration and double-sided bidding power-pool operation for both generation and demand. A compromise between the congestion revenue and the investment cost is used to determine the optimal expansion scheme, considering the outage rates of transmission lines. Both the level of congestion and the price deviation in the network are used as the driving indicators for the need of network expansion. The uncertainty in wind power generation introduces the probabilistic locational marginal prices (LMPs) and the estimated congestion revenue for a specific system configuration. The proposed TEP approach is applied on Garvers six bus system and the planning schemes results are assessed.

A recursive harmony search algorithm for security constrained transmission expansion planning

This paper proposes an enhanced recursive harmony search (HS) algorithm for the solution of the static transmission expansion planning (TEP) in deregulated environment considering security constraints. The modification of the recursive HS method in comparison to the traditional HS algorithm includes: i) the introduction of a variable bandwidth in the memory consideration and the pitch adjustment phases in the improvisation step of the algorithm and ii) the possibility of restarting the algorithm after the maximum number of improvisations is reached keeping the best solutions of the previous algorithm run. In this way, the probability of finding the optimum solution of the TEP problem is highly increased without burdening the computation time of the algorithm. The proposed recursive harmony search algorithm is tested and evaluated on Garvers test system for the classic static TEP problem. Moreover, a new cost-benefit TEP formulation is introduced which is solved by the proposed HS algorithm and tested on IEEE 24-bus reliability test system considering annual system operation.

Transmission network cost allocation based on a possible maximum used capacity for N-1 secure operation

This paper presents a power flow based approach to transmission fixed cost allocation problem in a pool based electricity market that takes into consideration N-1 secure annual operation. In this pricing approach, the cost of each facility is linked to the highest possible power flow a facility may face under a contingency situation in a year. Charges for each facility are based on the facility usage at that system snapshot that requests this highest possible maximum used capacity. Network usage is approximately determined by generalized distribution factors and three variations of the MW-Mile method for pricing counter-flows are investigated for the proposed cost allocation method. The proposed cost allocation method is applied to the IEEE 24-bus reliability test system and compared with other transmission pricing methods.