Approach For Contingency Ranking Research Articles

A Lyapunov spectrum based hybrid static and dynamic approach for contingency ranking

AbstractThe goal of contingency ranking is to provide a list of possible critical situations and rank them according to the severity of their impact on a power network. The methods of contingency ranking may be divided into two major categories: static and dynamic techniques. Static approaches are fast and can be implemented in real‐time, but they present different results depending on the parameter which has been selected for contingency ranking. Dynamic methodologies are more accurate than static ones, but they are time‐consuming. This paper presents a novel combined static and dynamic method for contingency ranking which takes advantage of both techniques and shows the performance evaluation for the hybrid method using accuracy and efficiency as criteria. The proposed method uses three well‐known static indices and the Lyapunov spectrum based dynamic approach to select the worst critical lines. IEEE 39‐bus (New England grid) and IEEE 118‐bus networks are utilized to verify the proposed method. The method provides speed and accuracy. One of the prominent features of the proposed approach is its ability to rank contingencies that lead to network load flow divergence.

Contingency ranking in static security assessment using teaching learning based optimization enhanced support vector regression

Static security assessment is one of the important aspects of power system. The traditional techniques used for the contingency ranking suffer from longer and complex calculations. It led to move towards pattern recognition approach for contingency ranking. In this paper, ranking module based on Support Vector Regression is designed to rank contingencies based on the severity. A new combined performance index is formulated to know the severity of contingency. The combined performance index is combination of voltage deviation performance index and line overload performance index. The parameters of SVR are selected using Teaching Learning Based Optimization. The proposed pattern recognition approach is validated on IEEE standard test systems.

Residential preferences for stable electricity supply and a reduction in air pollution risk: a benefit transfer study using choice modeling in China

This paper uses choice modeling surveys from the Chinese cities of Jiujiang, Jiangxi Province, and Changsha, Hunan Province, to identify residential preferences for simultaneously increasing the stability of the electricity supply and decreasing the health risks from air pollution. Air pollution in China is mainly attributable to externalities associated with the electricity supply. We employ a contingent ranking approach as our choice modeling method and test for the transfer of benefits for these preferences between the two sites. The original benefit estimates indicate that the implicit price for reducing the number of power breakdowns is about RMB 83 per times × year × household in Jiujiang and RMB 78 per times × year × household in Changsha, while the implicit price for reducing the duration of power breakdowns is statistically zero in Jiujiang and RMB 71 per times × year × household in Changsha. From the alternative perspective, we estimate that the annualized value of the statistical lifetime risk of cancer caused by air pollution over a 70-year period is RMB 50,844 per year in Jiujiang and RMB 67,146 per year in Changsha. This suggests that we do not reject benefit transferability based on the implicit price of the number of power breakdowns, but do reject it based on the number of deaths from cancer caused by air pollution.

Valuing Improvements in The Water Rights System in South Africa: A Contingent Ranking Approach1

Speelman, Stijn, Stefano Farolfi, Aymen Frija, and Guido Van Huylenbroeck, 2010. Valuing Improvements in the Water Rights System in South Africa: A Contingent Ranking Approach. Journal of the American Water Resources Association (JAWRA) 46(6):1133–1144. DOI: 10.1111/j.1752‐1688.2010.00480.xAbstract: In the context of increasing water scarcity, understanding is growing that irrigation water rights are important and that a lack of an effective water rights system constitutes a major reason for inefficient water management. This study carried out a contingent ranking experiment to study how smallholder irrigators in South Africa would value potential changes in water rights. Three specific dimensions of water rights, relevant for the South African case, are considered: duration, quality of title, and transferability. Results indicate that smallholder irrigators are prepared to pay considerably higher water prices if improvements are made in the water rights system. This implies that the proposed interventions in the water rights system would improve the efficiency and productivity of the small‐scale irrigation sector. The increased willingness to pay could furthermore also assist the South African government to reach the objective of increased cost recovery.

Artificial neural network model for voltage security based contingency ranking

The continual increase in demand for electrical energy and the tendency towards maximizing economic benefits in power transmission system has made real-time voltage security analysis an important issue in the operation of power system. The most important task in real time security analysis is the problem of identifying the critical contingencies from a large list of credible contingencies and rank them according to their severity. This paper presents an artificial neural network (ANN)-based approach for contingency ranking. A set of feed forward neural networks are developed to estimate the voltage stability level at different load conditions for the selected contingencies. Maximum L-index of the load buses in the system is taken as the indicator of voltage instability. A mutual information-based method is proposed to select the input features of the neural network. The effectiveness of the proposed method has been demonstrated through contingency ranking in IEEE 30-bus system. The performance of the developed model is compared with the unified neural network trained with the full feature set. Simulation results show that the proposed method takes less time for training and has good generalization abilities.

04/01856 An efficient approach for contingency ranking based on voltage stability: Bijwe, P. R. et al. International Journal of Electrical Power & Energy Systems, 2004, 26, (2), 143–149

04/01856 An efficient approach for contingency ranking based on voltage stability: Bijwe, P. R. et al. International Journal of Electrical Power & Energy Systems, 2004, 26, (2), 143–149

An efficient approach for contingency ranking based on voltage stability

This paper presents an efficient approach for line outage contingency ranking based on voltage stability concerns. This is achieved through non-iterative fast calculation of reactive support and voltage security indices using Norton's equivalent. Earlier approach required full AC load flow for every contingency simulation. Results for IEEE, 30 bus, 57 bus and an Indian 91 Bus Power Systems have been obtained to demonstrate the effectiveness of the algorithm.

Evaluating Health and Environmental Impacts of Pesticide Use: Implications for the Design of Ecolabels and Pesticide Taxes

This paper estimates the economic impacts of pesticide use on human health and on the environment to gather information on the structure of a possible pesticide tax and on the design of an “environmentally friendly” bread product. The relative importance of these different impacts is determined by what individuals are prepared to pay to avoid a case of human ill health and a unit of environmental damage, measured by bird species in decline. Willingness to pay is estimated using a contingent ranking approach, a variant of the standard contingent valuation method, which is capable of tackling the multidimensional effects associated with pesticide applications. The results suggest that consumers would be willing to pay substantial price markups for environmentally friendly bread loaves and, consequently, that a case could be made for a substantial pesticide tax, preferably differentiated byproduct type. It is also shown that individuals are on average only willing to tolerate between 7−8 cases of human illness to save an entire bird species.

Artificial neural network based contingency ranking method for voltage collapse

The paper presents a neural network-based approach for contingency ranking of voltage collapse. By using the singular value decomposition method, a Radial Basis Function (RBF) neural network is trained to map the operating conditions of power systems to a voltage stability indicator and contingency severity indices corresponding to transmission lines. The advantages of RBF neural network are demonstrated by applying it to contingency ranking and voltage stability assessment. Tests carried out on the IEEE 57-bus system are reported.

Valuing the Multiple Impacts of Pesticide Use in the UK: A Contingent Ranking Approach

The contingent ranking method was used to estimate the value of the human health and biodiversity impacts associated with pesticide applications, using a “green” consumer product as a payment vehicle. Specification testing showed that the standard conditional logit model provides a representation of these data preferable to the rank‐ordered logit variant. The resulting estimates ‐ which perform well in terms of standard validity tests ‐ show that, on average, consumers are only willing to tolerate between six and eight cases of human illness to save an entire species of farmland birds.

The non-use benefits of enhancing forest biodiversity: A contingent ranking study

Until recently, the majority of commercial forestry in the UK has comprised blanket planting of non-native coniferous species which typically do not offer a high level of biodiversity. However, the UK government, and consequently the UK Forestry Commission, are committed under various international agreements to conserve and enhance biodiversity in British forests. The study reported in this paper estimates that substantial non-use values would be generated if the Forestry Commission were to continue in its current efforts to develop management practices that promote an increase in biodiversity across a large area of its commercial holdings in remote parts of the country which are seldom visited. Rather than adopting a referendum-type contingent valuation method, a discrete-choice contingent ranking approach is used to estimate the general public's willingness to pay to increase the area of these forests managed under each of three forest management standards designed to offer increasing levels of biodiversity at the expense of commercial timber production. This permits relative preferences for different forest management standards to be measured at the same time as willingness to pay to enhance biodiversity.

Disamenity externalities from utility networks

Public utility service structure networks create visual disamenity externalities. A contingent ranking approach is used to value the welfare loss to individuals from utility service structures. Canals are used as a case example; and 1000 visitors were interviewed at a series of canal sites across England. Willingness-to-pay to avoid encountering pylons, other cable, and pipeline crossings amounted to £0.09, £0.10 and £0.05, respectively, for a 1% reduction in each of these utility service crossings over canals. Aggregating these values over the 3 million households that visit canals each year suggests a substantial welfare loss that forms the basis of a compensation claim by British Waterways against utility companies.

Valuing WTP for Diesel Odor Reductions: An Application of Contingent Ranking Technique

In valuing environmental change, it is desirable to use market data, which reflect citizens' willingness-to-pay (WTP) for a better quality environment. Unfortunately, market data often are unavailable for this purpose. When this happens, WTP often is elicited from survey data. Of course, there are risks that consumers may not respond to a survey in the same manner that they respond in a real market. These risks can be reduced by framing the hypothetical context of the market as realistically as possible. In most prior applications, contingent valuation efforts have employed some variant of a direct WTP question. However, requesting survey respondents to supply a dollar value for what is probably an unfamiliar commodity inherently is problematic. In contrast, the contingent ranking procedure asks participants to compare and rank alternatives, each describing a different tradeoff between the provision of an environmental good and its price. The contingent ranking approach is employed in this paper to estimate the value of reduced exposure to diesel vehicle odors from a 1984 survey of 140 respondents in the Philadelphia area. Diesel vehicle odors are related physically to the broader mobile source particulate emissions problem. In diesel fuel combustion processes, odor-causing unburned hydrocarbons are attached to particulate byproducts. Since particle removal technologies contribute in varying degrees to odor reduction, policies to reduce mobile source particulate emissions will provide the additional benefit of reducing the diesel odor nuisance type of externality. Given the pervasive nature of the diesel odor problem, even values to avoid a single odor contact of a few cents can amount in the aggregate to many millions of dollars. Thus, the benefit of odor reduction could be comparable to the magnitude of other health and welfare benefits associated with control of mobile source particulate emissions.'