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This paper presents a long-term deterministic linear simulation model for the Ethiopian hydropower system, intending to utilize the water stored in the rainy season throughout the year with minimum load shedding. Two cases are simulated and compared to historical data. The base case represents current load levels, and the second case represents a load level increase. The results show that the Ethiopian hydropower system has a great deal of flexibility to be operated in a more efficient way to minimize load shedding. The results also show that the system can support a 50% load increase with minimum load shedding, mostly when the load demand exceeds the total generating capacity. The contribution of this paper is to apply a standard hydropower model for Ethiopia to estimate the potential of the Ethiopian hydropower system to avoid or minimize load shedding with improved generation and operation planning.

This article represents the application of the thyristor controlled phase-shifting transformer (PST) capable to maintain the phase shift between the input and output voltage phasor within defined range during rapid transient. The positive influence was illustrated by PST installation in power distribution system of Boguchany Dam, which led to increasing of maximum generating capacity of Boguchany Dam, which was limited due to dynamic transient instability of generators.

Considering that the energy matrix of Honduras has undergone a drastic change during the last years due to the introduction of variable renewable energies, this change leads us to study the impact that is generated in the national interconnected system (SIN), this impact would be mainly influenced by the variability of renewable sources, given the sudden changes in both the increase and decrease of generation. In response to this impact a new methodology is proposed in the management of reserves in the SIN, different from those currently consider in the dispatch of energy. This methodology promotes a ramp reserve which consists in having the availability of rise or fall a quantity of generation in a given time, thus being able to absorb the falls or rises of large generation blocks that occur by any variant in the variable renewable generation (GRV). The calculation of the reserves will be obtained from the historical data of the ramps that occurred due to the GRV. The purpose of this calculation, besides improving the quality of the national interconnected system, is to make a comparison of the costs that would be generated by maintaining an available ramp reserve, with the costs of maintaining the system with the methodologies that it currently has.

Interval number contains both the average and change information. This paper presents two second-order grey models suitable for the forecasting of binary and ternary interval number, named BINGM (2, 1) and TINGM (2, 1). The overall development coefficients of two models are taken as an accurate number, and the grey inputs are taken as interval numbers. By this method of parameter setting, the models are suitable for the interval number series directly, and no need to transform the interval number series into the accurate number series. The overall development coefficients, grey inputs, and constants in the forecasting formulas of TINGM (2, 1) and BINGM (2, 1) are all determined by the new information priority principle (NIPCM), instead of the least square method (LSM). The wind power generating capacity and the generating capacity of China are predicted based on BINGM (2, 1) and TINGM (2, 1). The forecasting performance is better than the models based on GM (1, 1).

One of the major factors in planning, design, operation and maintenance of the power system is the reliability. The electric power planning concentrates on the load forecast for the future. The future expectation of electric load needs the load history to data. The present study concentrates on one of the terms used in the reliability, which is Loss of Load Probability (LOLP). This term followed when the loss of load happens as the electric load exceeds the available generating capacity of the system. As a measure of the LOLP it means how much in time, the load exceeds the available capacity of the system. Four power stations combined and considered to form one power system. The LOLP calculated for the system under different loads. This type of consideration is helping to plan the future of the system and finding the effect of load on power system reliability. At the same time, the LOLP-FOR model investigated.

Policy guides decision. This paper examines policy in the Nigerian Electric Power Sector (NEPS) to cut transmission losses (TL) and improve capacity factor (CF) to 5% and 90%, respectively. A System Dynamics (SD) model developed in STELLA software package was employed to analyze this policy. Secondary data were sourced from: a) National Control Centre (NCC); b) Nigeria Electricity Regulatory Commission (NERC); and c) National Bureau of Statistics (NBS). Two scenarios were considered, the pre-privatized and improved scenarios. Results showed that at TL of 5% and CF of 90% i) electricity outages would be reduced by about 17.84% from 2010 to 2050; ii) over the study period a capacity of 473 MW (about 94.6 MW/year) would be fed back into the system; iii) transmission losses of 3,400 GWh would have been curtailed by 2050; and iv) cutting down TL and improving CF alone in NEPS will not totally curtail electricity outages and deficiencies in NEPS. Therefore, the study recommends that increasing generating capacity (MW) would go a long way in curbing electricity deficiencies. Renewable energy sources could be a better choice. Further studies are recommended in this regard. It was proven by the study that a system dynamics modelling approach is suitable for examining long-term behavior and dynamic feedback in Nigeria's electricity sector.

Evaluating the risk of capacity deficit in large interconnected power systems is an important task in planning studies in order to supply the demand in the system at a certain risk level. It makes it possible to identify in which parts of the system reinforcements are needed in terms of generating capacity and/or interconnections. In modern power systems, with tie lines interconnecting countries and continents as well as an increasing amount of intermittent renewable resources, areas become dependent on each other for generating capacity not only under rare hazardous operating conditions but also in what can be considered as normal operation. This paper presents a novel way of taking inter-area load correlation into account when calculating the risk of capacity deficit by applying Copula sampling. The Monte Carlo simulation method is applied in addition to a Cross-Entropy based importance sampling technique to reduce computation time. The resulting procedure is a computationally effective general method of evaluating the risk of capacity deficit in a large scale multi-area interconnected power system.

Extrapolations of ‘Swanson's Law’ (a learning curve) and its replot project that solar cells (predominately crystalline Si so far) can match the world's current power generating capacity at lower costs than fossil fuels and with a net gain in jobs — all by 2032. Existing wind and solar cell resources are sufficient for this transition. If wind and solar variability can be accommodated, greenhouse gas emissions (from burning fossil fuels) can be eliminated 18 years earlier than others propose. This is probably necessary to avoid disastrous climate change, which is likely irreversible over a 1000's-of-years-time-frame, if all fossil fuels are burned.

We describe the algorithm for the adequacy discrete optimization of electric power systems (EPSs). The algorithm is based on the expectation of dual-use estimates obtained when evaluating the EPS carrying adequacy through the Monte-Carlo method based on restrictions of generating capacity in the EPS nodes and communication capacity of EPS. The developed algorithm is elected. Reducing the number of the addressed options for EPS expansion is performed depending on the analysis of the dual-estimate expectation. We present practical applications for experimental investigations into the algorithm.

Generating capacity adequacy studies play a significant role in long term capacity planning. Risks of capacity deficits are usually reported in the form of one or more average quantities, which cannot fully convey the nature of the risks being faced. Chronological Monte Carlo simulations may be used to construct comprehensive multi-dimensional risk profiles, but such profiles tend to be difficult to interpret. This paper proposes the use of a clustering method to partition the risk profile into clusters of similar outcomes with associated probabilities. The results are presented in accessible tabular form, and prototypical scenarios can be analysed in detail to provide further insight.

• Paper presents the practical experience in evaluating adequacy of generating capacity by different regions in the Western interconnection. • It also outlines different probabilistic methodologies and tools used to calculate reliability indexes such as LOLE, EUE, etc in the Western Interconnection. • The paper made an attempt to emphases why industry today needs enhanced methodologies and tools and how to resolve some of the known obstacles. • Adequacy assessment of systems with ongoing integration of variable resources such as wind and solar is among new requirements to enhance the present methodologies and tools. • Address planning for adequate reliability under high penetration of renewable

Short-term load forecasting is an essential instrument in power system planning, operation & control. Many operating decisions are based on load forecasts, such as dispatch scheduling of generating capacity, reliability analysis & maintenance planning for the generators. This paper discusses significant role of artificial intelligence (AI) in short-term load forecasting (STLF), that is, the one hour-ahead forecast of the power system load. A new artificial neural network (ANN) has been designed to compute the forecasted load. Historical electricity load data has been used in the modeling of ANN. The ANN model is trained on hourly data from PJM Electricity Market & UPPCL and tested on out-of-sample data. Simulation results obtained have shown that one hour-ahead forecasts of load using proposed ANN is very accurate with very less error.

The European electricity market has been constructed as “energy only market” without the compensation for the costs of generation adequacy. Such as a market is able to operate in the presence of the capacity excess. However, gradually the power reserve margins have been diminishing causing the fears of the power balancing in the coming years. One of the measures to stimulate the investment in power generating capacity is the introduction of capacity or power markets. Several countries such as Spain, Italy and Sweden introduced such markets in various forms several years ago. The uncoordinated rush for new market forms has raised the fears in the European Commission that new markets may have the negative impact on the competition as well as on the energy policy of the European Union. The paper presents the application of fuzzy sets for the analysis of the requirements for capacity markets and it demonstrates that such a methodology is not only a new approach but also it is the best way for such analyses.

In this paper, different effects on the efficiency of wind power generation between automatic alignment of the wind turbine and cable twisting then untwisting, has been studied. Then the prevent cable twisting control strategy of wind turbine yaw system is proposed to reduce probability of occurrence of cable twisting, thus it helps to improve the generating capacity of wind power generation. Finally, the configuration software MCGS used to create the simulation model of wind turbine's yaw control systems and implement the relevant module control method. MCGS simulations prove the validity of proposed prevent cable twisting control strategy.

The Electric Reliability Council of Texas (ERCOT) experienced record weather extremes in 2011. During the morning of February 2 the coldest temperatures and wind chills seen in over 20 years caused an unprecedented amount of generating capacity to trip off-line or fail to start due to frozen instrumentation and controls. At the same time, customer demand for electricity was approaching record winter peak levels. In order to prevent an uncontrolled drop in system frequency, ERCOT implemented its Energy Emergency Alert (EEA) plan. Through the morning almost 1,500 MW of interruptible load was dropped and up to 4,000 MW of firm load was subjected to rotating outages until early afternoon. Preparation s ERCOT made for the frigid temperatures and the sequence of events will be discussed, along with lessons learned by generators, transmission and distribution utilities and ERCOT from the experience. These lessons learned benefitted ERCOT operations during another period of cold weather the following week and also proved their value a few months later during summer operations when all available generating capacity was needed. The summer of 2011 also presented severe operating challenges for the ERCOT electric grid. The summer was the hottest in recorded history in Texas with an unprecedented 12 month drought and records set for the number of days with high temperatures exceeding 100 degrees. Electric demand exceeded that which would be expected with normal summer temperatures by 8%. Electric generating plants were stressed to their limits to meet the high and persistent customer demand. The system was most stressed during August when demands reached their highest and generators began showing the effects of several months of operating at their maximum capacity. ERCOT implemented its EEA plan on seven days during the summer and shed interruptible load on two of those days in August. ERCOT managed to avoid any rotating outages during the hottest summer in history. There were a number of lessons learned from operations during the summer of 2011 that will be discussed. The importance and benefit of communications with the public, news media, public safety authorities, regulators and legislators about system conditions was proved. The assistance provided by increased coastal wind generation during summer days was also shown. In addition it was learned that long term projections of generation reserve margins can be misleading when applied to the short term and ERCOT is changing the way it presents resource adequacy reports in the future.

This paper proposes a standing assistance control with a patient's load estimation for our robotic walker system. Our developing robotic walker realizes a standing assistance using its support pad which is actuated by novel assistance manipulator mechanisms on its body with four parallel linkages. Our system assists a standing motion using a remaining physical strength of patients maximally in order not to decrease their force generating capacity. For realizing this function, this paper proposes the following two topics. The first topic is an load estimation scheme of a patient who uses our assistance system. Our developed system measures a body motion and the applied force of a patient during standing assistance, and our system estimates the load of trunk, knee and ankle joint using a linkage model which approximates the human body. The second topic is a combination of force and position control. According to the estimated load of a patient during standing motion, our control system selects more appropriate control method from them and realizes the standing assistance using the physical strength of the patient. The performance of our system is verified by experiments using our prototype.

Demand side management (DSM) can help reduce demand of the system, resulting in less generating capacity and less total production cost in the future. Generally, each DSM activity, e.g., replacing old with new higher efficiency equipment, has its own cost. Its worth in the system may be used as one of the decision components. Therefore, the methodology in evaluating the DSM worth under the framework of long-term generation system planning will be proposed in this paper. With the obtained results, the system planners will be able to select DSM programs more appropriately.

Solar SCADA systems need to take advantage of the great repetition intrinsic in solar plant design. This paper presents several key facets of a SCADA system designed specifically for utility scale solar generating assets. The presented SCADA system gathers and stores approximately 400 points per MW of installed photovoltaic generating capacity. This paper discusses both the hardware and software architecture of this SCADA system including design choices related to point types and the data system used to aggregate the information. Means and methods of data analysis are presented to enable rapid responses to forced AC and DC outages in concert with JSI's utility partners.

The ability of the liberalised energy markets to trigger investment in the generation capacity required to maintain an acceptable level of security of supply risk has been - and will continue to be - a topic of much debate.

Earlier research has shown that adding wind capacity to a network can lower the total annual operating cost of meeting a given pattern of loads by displacing conventional generation. At the same time, the variability of wind generation and the need for higher levels of reserve generating capacity to maintain reliability standards impose additional costs on the system that should not be ignored. The important implication for regulators is that the capacity cost of each MW of peak system load is now much higher. Hence, the economic benefits to a network of using storage and controllable load to reduce the peak system load will be higher with high penetrations of wind generation. These potential benefits will be illustrated in a case study using a test network and the SuperOPF. An important feature of the SuperOPF is that the amount of conventional generating capacity needed to maintain Operating Reliability is determined endogenously, and as a result, it is possible to determine the net social benefits of relying more on an intermittent source of generation, such as wind capacity, that lowers operating costs but increases the cost of maintaining System Adequacy. The capabilities of the SuperOPF provide a consistent economic framework for evaluating Operating Reliability in real-time markets and System Adequacy for planning purposes. Basically, a financially viable investment requires that the reductions in the total annual costs of the existing system should be larger than the annualized cost of financing the addition of, for example, wind generation to a network. The scenarios considered make it possible to determine 1) the amount of conventional generating capacity needed to meet the peak system load and maintain System Adequacy, 2) the amount of missing money paid to generators to maintain Financial Adequacy, 3) changes in the congestion rents for transmission that are collected by the system operator, and finally, 4) the total annual system costs paid by customers directly in the Wholesale Market and, indirectly, as missing money. The results show that the benefits (i.e. the reduction in the total annual system costs) from making an investment in wind capacity and/of upgrading a tie line are very sensitive to 1) how much of the inherent variability of wind generation has to be accommodated on the network, and 2) how the missing money paid to conventional generators is determined (e.g. comparing a regulated market and a deregulated market).

The objective of this research was to determine the adequacy of the rule-of-thumb reserve margin for Indiana's electricity generation system and the adjustment of the reserve margin. To achieve the objective, a statistical model is constructed to evaluate system reliability. Monte Carlo Simulation is applied to build the capacity availability probability distribution as the generation model. Hourly loads and daily peak loads of 2003, 2004 and 2005 are used to form the load models. Then, the generation model and the load model are convoluted to calculate the loss of load probability (LOLP) for Indiana's electricity generation system. Results show that the reliability standard is more than satisfied for 2003 and 2004. However, for 2005, the estimated LOLPs do not satisfy the standard, suggesting capacity expansion for the system is needed. By uniformly shifting load curves up or down to adjust the estimated LOLPs until the industry standard is satisfied, the new reserve margin for each load model is found. This analysis suggests that even for 2005 only a small increase in generating capacity is needed.

The primary goals for moving from a regulated electric supply industry to a deregulated market were to reduce the average costs paid by customers and to promote efficient long-term investment. However, it is still highly debatable whether either of these goals has been realized in the northeastern states. Regulators have rejected the rationale for long-run competitive prices in an energy-only market, and instead, they have adopted short-run competitive prices as the criterion for judging the performance of a spot market. Although they have been reasonably successful in maintaining this strategy, by doing so, they have introduced the problem of “missing money” for generators. As a result, the northeastern states have adopted or proposed some form of Installed CAPacity market (ICAP) to provide generators with additional income to cover the missing money. Although most regulators agree that generators need some supplementary income, there is no general agreement about how this extra income should be provided. The objective of this paper is to discuss and evaluate how and why the designs of an ICAP market have evolved from New York to PJM to New England. In this paper, we explained 1) why investors have been reluctant to build new generating capacity in New York, and 2) the rationale for the alternative designs proposed in PJM and New England. Finally, we presented the results of economic experiments that conducted in February 2007 and October 2007 by the Power System Engineering Research Center (PSERC) at Cornell University to test the performance of a simplified Forward Capacity Market (FCM) proposed for New England.

ERCOT offers its market participants the simultaneous opportunity to increase the value of their assets and reduce operating costs to meet customer load and ancillary obligations. ERCOT has enabled its participants to do this through the facilitation of a day-ahead market for ancillary services in combination with a zonal real-time energy market. The market for ancillary services is comprised of four standard products that can be hedged and are actively traded. These products include Responsive Reserve Service (RRS), Non Spinning Reserve Service (NSRS), Up Regulation Service (URS) and Down Regulation Service (DRS). With the addition of substantial amounts of new wind generating capacity in Texas, the need for ancillary services have increased.

According to the latest report, the US has been the fastest growing wind power market in the world for the past few years. Wind projects accounted for more than one third of all new US electric generating capacity in 2007, and are on a projected track to becoming a convincing contributor to the US power mix. The Department of Energy estimates that wind power will generate 20 percent of nation's electricity by 2030. This aggressive growth in wind power will pose a great challenge to the utility industry.

Load forecast uncertainty is an important factor in long range system planning and has been shown to have a significant impact on the calculated reliability indices in generating capacity studies. In general, a higher capacity reserve is required to satisfy a future uncertainty load than to serve a known load, at a specified level of reliability. Load forecast considerations are also important in composite generation and transmission system reliability studies, and their associated probability distributions. This paper examines the effects of load forecast uncertainty in bulk system reliability assessment incorporating changes in system composition, topology, load curtailment policies and bus load correlation levels.

This paper illustrates the effects on the load point and system reliability indices of a composite generation and transmission system of adding wind energy facilities with different degrees of wind speed correlation. The studies were conducted on the two test systems using a state sampling Monte Carlo approach. The analyses show the impacts of adding wind generating capacity at various locations in the two test systems and the effects on the load point and system indices of varying the wind penetration and the wind speed correlation levels. The studies presented illustrate the importance of considering wind speed correlation in the reliability assessment of composite generation and transmission systems containing large scale wind energy facilities.

Summary form only given. In this paper a stochastic dynamic optimization model is used to analyze the effect of different market designs on generation investment in restructured power systems. The expansion decisions of profit-maximizing investors are simulated under four different market designs: Energy only, capacity payment, capacity obligation, and capacity subscription. The results show that the overall social welfare is reduced compared to a centralized social welfare optimization for the first three policies. In particular, an energy only market with a low price cap leads to insufficient generation investments. Capacity payments and obligations give additional investment incentives and more generating capacity, but also result in a considerable transfer of wealth from consumers to producers due to the capacity payments. In contrast, the capacity subscription policy increases the social welfare, and both producers and consumers benefit. This is possible because capacity subscription explicitly utilizes differences in consumers' preferences for uninterrupted supply. This advantage must be weighed against the cost of implementation, which is not included in the model.

The paper presents an analytical method for evaluating the adequacy of planned generating capacity and tie capacity in two Interconnected Power Systems (IPS). Each Interconnected Power System is regarded as concentrated that is to say all their internal transmission lines are absolutely reliable and have no limitations concerning transfer capability. Probability function of capacity deficiency and surplus in such systems is well characterized by normal distribution, that allows finding rather simple and at the same time sufficiently closing solution for LOLP depending on operating reserves of Interconnected Power Systems and Tie Capacity. The examples analyzed consider the influence installed generating capacity in each system and tie capacity on reliability of two Interconnected Power Systems.

Generating capacity adequacy evaluation is performed to evaluate the ability of the system generating capacity to meet the total system load. There are several basic reliability indices normally used to represent this ability and a wide range of methods have been developed to perform the evaluation. Although the basic reliability indices have been used for some time, there are still some misconceptions that need to be examined and discussed. Two computer programs have been used to conduct basic generating capacity adequacy evaluation. The simulation program provides the opportunity to extend the basic indices normally calculated using an analytical program to include index probability distributions. These concepts are illustrated in this paper together with some fundamental considerations regarding the basic indices and their interpretation. The concepts presented are illustrated by application to two published reliability test systems.

This paper addresses the issue of generating capacity adequacy in power systems with considerable share of wind generation. It shows on a hypothetical example derived from the WECC system (western US interconnection) how different percentages of wind penetration affect this adequacy. For this purpose, the popular LOLP - loss of load probability (or more accurately, LOLE ? loss of load expectation) is used as an objective, probability based, index. It is compared to reserve margin, another popular, deterministic index. Two systems with the same reserve margin or largest unit reserve can have very different risks of being unable to serve the load. It is shown that this discrepancy exacerbates as wind penetration increases.

Reliability is one of the most important criteria which must be taken into consideration during planning and operation phases of a power system even (or may be, particularly) in the time of disintegration, deregulation and competition. This paper considers the assessment of generating capacity reliability, in terms of adequacy; computationally efficient algorithms and theirs computer realization (GRA program). The GRA (generating reliability assessment) computer program main features are listed. The paper illustrates the utilization of the GRA program in Polish power system studies.

This paper discusses an unconventional concept- tariff linked to frequency. This new concept has been introduced in India at the inter-state level, starting from mid 2002, through the three-part tariff for central generating stations, the so called availability based tariff (ABT). In this scheme overdrawals are costly when the grid is short on generation, and are cheap when the grid has surplus generating capacity. Similarly any oversupply is paid for at a high rate when frequency is below 50.0 Hz and at a low rate when the frequency is above 50.0 Hz. Underdrawal and undersupply also get the same treatment.

The PJM Energy Market has been called by some "the most successful Market in North America." The PJM Market reaches into eight states and the District of Columbia, serving 11 million customers with a peak load of over 64000 MW using generating capacity in excess of 70000 MW. This paper defines the drivers behind PJM's Markets, provides an overview of the PJM Markets, and looks at the future plans for PJM's Markets.

This paper reports the analysis results of the solar energy resource and potential electricity generating capacity from building-integrated photovoltaics (BIPV) systems in Hong Kong. The monthly average daily solar radiation on a horizontal surface and the daily sum distributions of solar radiation show that the solar radiation intensity is quite high in Hong Kong except the wet period from January to March. The mean annual global radiation is 4646.8 MJ/m/sup 2/. The potential electricity generating capacity from BIPV systems is estimated to be 10.5 TWh which is about 35% of the total annual electricity supply (29.9 TWh) in Hong Kong in 1995 if the shadow facades of the high-rise buildings are excluded. The BIPV electricity prices are estimated and compared with the local grid electricity prices. The results illustrate a bright future for BIPV applications in the next century in Hong Kong.

Located in the central Andes mountains in Peru, the 900 megawatt C.H. Antunez de Mayolo hydroelectric facility (Mantaro) generates approximately 70% of the region's power, which includes the capital city of Lima (population 7 million). In a remote region approximately 350 kilometres east of Lima, at an altitude of over 2500 meters above sea level, the Mantaro facility (named after the river upon which it is situated) is a major engineering feat in itself. The headrace tunnel servicing the plant, 4.8 metres (15 feet) in diameter, has been bored through the Andes mountains and extends for an extraordinary distance of 19.8 kilometres (66000 linear feet). Since its construction in the early 1970s this facility has been unable to meet its maximum generating capacity due to a gradual loss of head pressure. The purpose of the inspection is to determine the cause of this problem and to identify possible solutions. The paper describes the ROV developed to carry out the inspection. The ROV incorporates an application designed sensor package, multiple camera suite, dual sonar, NDT probe, five function manipulator and a concrete coring drill.