- Email: [email protected]
00700 PSS-control as an ancillary service
06 Electrical power supply and utilization (economics, policy, supplies, forecasts) a m e t e r s such as wellbore geometries, working fluid properties, circulation rates, and regional properties including basal heat flux and formation rock type. Energy extraction is strongly affected by fluid residence time, heat transfer contact area, and formation t h e r m a l properties. W a t e r a p p e a r s to be the most a p p r o p r i a t e working fluid. The effects of tubing properties and casing lengths are of second-order. On the basis of a sensitivity study, a Best Case model was simulated, and results c o m p a r e d against the g e o t h e r m a l fluid r e q u i r e m e n t s of existing power generation plants that use l o w - t e m p e r a t u r e g e o t h e r m a l fluids. Even assuming ideal work conversion to electricity, a W B H X c a n n o t supply sufficient energy to generate 200 k W e at the onset of pseudo-steady-state (PSS) conditions. Using realistic conversion efficiencies it is unlikely that the system would be able to generate 50 k W e at the onset of PSS.
06/00698 Prediction of hourly energy consumption in buildings based on a feedback artificial neural network Gonz(dez, P. A. and Zamarrefio, J. M. Energy and Buildings, 2005, 37, (6), 595 601. In this p a p e r a new approach for short-term load prediction in buildings is shown. The m e t h o d is based on a special kind of artificial neural network (ANN), which feeds back a part of its outputs. This A N N is trained by means of a hybrid algorithm. The new system uses current and forecasted values of temperature, the current load and the hour and the day as inputs. The performance of this predictor was evaluated using real data and results from i n t e r n a t i o n a l contests. The achieved results d e m o n s t r a t e the high precision reached with this system.
06/00699 Pricing for load and wheeling charge considering transmission paths in deregulated power markets Li, R. et al. International Journal of Electrical Power & Energy Systems, 2005, 27, (7), 496 505. This p a p e r proposes a practical m e t h o d to derive reasonable load prices and wheeling charges in a d e r e g u l a t e d power market. The proposed pricing model not only ensures the recovery of expense for utilities, but also provides reasonable electricity prices for consumers. A competitive m a r k e t e n v i r o n m e n t is defined at the beginning of this p a p e r to include i n d e p e n d e n t power producers (IPPs), utilities and customers. The pricing m o d e l is f o r m u l a t e d m a t h e m a t i c a l l y as a nonlinear optimization problem. Based on the optimal solution, the transmission path can be identified by investigating power flow with respect to generator outputs and load d e m a n d s through sensitivity analysis. The proposed approach is applied to an I E E E - 3 0 bus system, where the simulation results d e m o n s t r a t e d that the proposed pricing strategy can also be used for the transmission congestion and loop flow problems.
06/00700
PSS-control as an ancillary service
A n d r e o i u , A. and Bhattacharya, K. Electric Power Systems Research, 2005, 74, (3), 391 399. This p a p e r proposes that the control action provided by power system stabilizers (PSSs) to enhance system stability, be considered as one of the system ancillary services. To this effect, there is a need to formulate a p p r o p r i a t e financial c o m p e n s a t i o n mechanisms for the generators, in return for their service. A t the same time, it is also i m p o r t a n t to identify which PSS is more crucial for system stability, and also those that could be even d e t r i m e n t a l to overall system stability. A cooperative game theory-based approach using the Shapley value criterion is developed in this p a p e r to identify the marginal contribution of each PSS to the total control effort. Accordingly, the m e t h o d outlines a p p r o p r i a t e allocation of p a y m e n t to each generator involved in providing the PSS-control.
06•00701 Seamless electricity trade between Canada and US Northeast Bernard, J.-T. et al. Energy Policy, 2005, 33, (14), 1853 1863. W e analyse how the wholesale electricity m a r k e t deregulation could modify exchanges between three C a n a d i a n regions (Ontario, Q u e b e c and New Brunswick) and two US regions (New Y o r k and New England), on the base of their loads and available resources when the regulatory change took place in 1997. The authors find that the pre1997 exchanges already m a d e possible fuel cost savings of $397.2 million per year while deregulation adds a n n u a l savings of $358.7 million. C a n a d i a n regions are the main beneficiaries under the a s s u m p t i o n that exports are priced at the m a r g i n a l costs of the i m p o r t i n g regions. Imports from the C a n a d i a n regions, although significant, are not large enough to lower the m a r g i n a l costs of the US regions. H e n c e electricity d e r e g u l a t i o n across the b o r d e r should not significantly decrease prices in the US regions although the latter are b e c o m i n g more d e p e n d e n t upon imports from Canada. Greenhouse gas emissions increase by 4.3 Mt CO2 eq. in the wake of the open wholesale electricity m a r k e t because of the low cost of coal, particularly
in Ontario. E n v i r o n m e n t a l concerns and the limited availability of additional hydroelectric power in C a n a d a could change the trade patterns as electricity d e m a n d continue to grow.
06/00702 The coordinated control of SVC and excitation of generators in power systems with nonlinear loads Ruan, Y. and Wang, J. International Journal of Electrical Power & Energy Systems, 2005, 27, (8), 550 555. Based on the feedback linearized technique and control of differential and algebraic systems, the exact linearization design is p r e s e n t e d in this paper for static vat c o m p e n s a t o r (SVC) and generator excitation controllers in power systems with non-linear loads. It can improve both the power angle stability of generators and the voltage behaviour at the SVC location. Simulation results indicate that this control m e t h o d has a good effect and superiority.
06/00703 The implications of the Kyoto project mechanisms for the deployment of renewable electricity in Europe del Rio Gonz(dez, P. et al. Energy Policy, 2005, 33, (15), 2010 2022. E U energy/environmental policy has at least two major and interrelated goals: to increase the p e r c e n t a g e of electricity from renewable energy sources (RES-E) and to control the emission of G H G cost efficiently. These two goals could be in conflict. This paper explores one aspect of this conflicting relationship, namely the effect that the use of the Kyoto Protocol project m e c h a n i s m s ( C D M / J I project) may have on the d e p l o y m e n t of R E S - E within E U borders. The main conclusion is that, under certain assumptions (i.e. no m a n d a t o r y E U R E S - E quota), C D M / J I projects m i g h t reduce the incentive to deploy R E S - E within E U borders because they would allow E u r o p e a n power companies to comply with G H G targets in a cheaper way than if they reduced emissions by investing in renewable electricity in Europe. This is problematic, since many benefits from renewable electricity are local and these would be gone. This situation would be different if a m a n d a t o r y R E S - E q u o t a (combined with an EU-wide TGC scheme) was implemented. In this case, the R E S - E target would be fulfilled and C D M / J I projects would only affect R E S - E d e p l o y m e n t exceeding the target.
06/00704 Transfer of transient surge voltage through XLPE cable winding transformer (Dryformer) circuits Manyahi, M. J. et al. International Journal of Electrical Power & Energy Systems, 2005, 27, (8), 602 609. E x p e r i m e n t and simulation results of conventional transformer design have shown that there are considerable differences in the characteristics of the surge voltages that are i m p o r t a n t in deciding the transferred voltages, d e p e n d i n g on w h e t h e r it is from primary to secondary or vice versa. Dryformer is a new technological advance of dry power transformer, which is constructed from X L P E insulated high voltage cables as its winding, and is designed to provide a direct link between ultimate customers and transmission systems in one step transformation. It is i m p o r t a n t therefore to have a b e t t e r understanding of Dryformer behaviour in regard to transient surge voltage transfer between its circuits. This p a p e r presents the application of a high frequency m o d e l for the study of transient surge voltage transfer between the Dryformer circuits due to surges having various steepness, a m p l i t u d e and duration characteristics, which are expected in practise. The model is based on the creation of an R L C G network that gives the same a d m i t t a n c e function as that obtained experimentally at the transformer terminals. The validity of the f o r m u l a t e d model has been verified by comparing the model predictions with experimentally obtained voltage transfer function. The m o d e l is successfully applied in estimating the t h r e a t levels posed to Dryformer winding and customer connected e q u i p m e n t due to transient overvoltages.
06/00705 Transmission congestion management in bilateral markets: an interruptible load auction solution Tuan, L. A. et al. Electric Power Systems Research, 2005, 74, (3), 379 389. This paper d e m o n s t r a t e s that a p p r o p r i a t e invocation of interruptible loads by the i n d e p e n d e n t system operator (ISO) can aid in relieving transmission congestion in power systems. A n auction m o d e l is proposed, for an ISO operating in a bilateral contract d o m i n a t e d market, for real-time selection of interruptible load offers while satisfying the congestion m a n a g e m e n t objective. The proposed congestion m a n a g e m e n t scheme using interruptible loads can specifically identify load buses where corrective measures are n e e d e d for relieving congestion on a particular transmission corridor. The N 1 contingency criterion has been taken into account to simulate various cases, and hence, examine the effectiveness of the proposed method. It has been shown that the m e t h o d can assist the ISO to remove the overload from lines in both n o r m a l and contingency conditions in an o p t i m a l manner.
Fuel and Energy Abstracts
March 2006
105
06/00698 Prediction of hourly energy consumption in buildings based on a feedback artificial neural network Gonz(dez, P. A. and Zamarrefio, J. M. Energy and Buildings, 2005, 37, (6), 595 601. In this p a p e r a new approach for short-term load prediction in buildings is shown. The m e t h o d is based on a special kind of artificial neural network (ANN), which feeds back a part of its outputs. This A N N is trained by means of a hybrid algorithm. The new system uses current and forecasted values of temperature, the current load and the hour and the day as inputs. The performance of this predictor was evaluated using real data and results from i n t e r n a t i o n a l contests. The achieved results d e m o n s t r a t e the high precision reached with this system.
06/00699 Pricing for load and wheeling charge considering transmission paths in deregulated power markets Li, R. et al. International Journal of Electrical Power & Energy Systems, 2005, 27, (7), 496 505. This p a p e r proposes a practical m e t h o d to derive reasonable load prices and wheeling charges in a d e r e g u l a t e d power market. The proposed pricing model not only ensures the recovery of expense for utilities, but also provides reasonable electricity prices for consumers. A competitive m a r k e t e n v i r o n m e n t is defined at the beginning of this p a p e r to include i n d e p e n d e n t power producers (IPPs), utilities and customers. The pricing m o d e l is f o r m u l a t e d m a t h e m a t i c a l l y as a nonlinear optimization problem. Based on the optimal solution, the transmission path can be identified by investigating power flow with respect to generator outputs and load d e m a n d s through sensitivity analysis. The proposed approach is applied to an I E E E - 3 0 bus system, where the simulation results d e m o n s t r a t e d that the proposed pricing strategy can also be used for the transmission congestion and loop flow problems.
06/00700
PSS-control as an ancillary service
A n d r e o i u , A. and Bhattacharya, K. Electric Power Systems Research, 2005, 74, (3), 391 399. This p a p e r proposes that the control action provided by power system stabilizers (PSSs) to enhance system stability, be considered as one of the system ancillary services. To this effect, there is a need to formulate a p p r o p r i a t e financial c o m p e n s a t i o n mechanisms for the generators, in return for their service. A t the same time, it is also i m p o r t a n t to identify which PSS is more crucial for system stability, and also those that could be even d e t r i m e n t a l to overall system stability. A cooperative game theory-based approach using the Shapley value criterion is developed in this p a p e r to identify the marginal contribution of each PSS to the total control effort. Accordingly, the m e t h o d outlines a p p r o p r i a t e allocation of p a y m e n t to each generator involved in providing the PSS-control.
06•00701 Seamless electricity trade between Canada and US Northeast Bernard, J.-T. et al. Energy Policy, 2005, 33, (14), 1853 1863. W e analyse how the wholesale electricity m a r k e t deregulation could modify exchanges between three C a n a d i a n regions (Ontario, Q u e b e c and New Brunswick) and two US regions (New Y o r k and New England), on the base of their loads and available resources when the regulatory change took place in 1997. The authors find that the pre1997 exchanges already m a d e possible fuel cost savings of $397.2 million per year while deregulation adds a n n u a l savings of $358.7 million. C a n a d i a n regions are the main beneficiaries under the a s s u m p t i o n that exports are priced at the m a r g i n a l costs of the i m p o r t i n g regions. Imports from the C a n a d i a n regions, although significant, are not large enough to lower the m a r g i n a l costs of the US regions. H e n c e electricity d e r e g u l a t i o n across the b o r d e r should not significantly decrease prices in the US regions although the latter are b e c o m i n g more d e p e n d e n t upon imports from Canada. Greenhouse gas emissions increase by 4.3 Mt CO2 eq. in the wake of the open wholesale electricity m a r k e t because of the low cost of coal, particularly
in Ontario. E n v i r o n m e n t a l concerns and the limited availability of additional hydroelectric power in C a n a d a could change the trade patterns as electricity d e m a n d continue to grow.
06/00702 The coordinated control of SVC and excitation of generators in power systems with nonlinear loads Ruan, Y. and Wang, J. International Journal of Electrical Power & Energy Systems, 2005, 27, (8), 550 555. Based on the feedback linearized technique and control of differential and algebraic systems, the exact linearization design is p r e s e n t e d in this paper for static vat c o m p e n s a t o r (SVC) and generator excitation controllers in power systems with non-linear loads. It can improve both the power angle stability of generators and the voltage behaviour at the SVC location. Simulation results indicate that this control m e t h o d has a good effect and superiority.
06/00703 The implications of the Kyoto project mechanisms for the deployment of renewable electricity in Europe del Rio Gonz(dez, P. et al. Energy Policy, 2005, 33, (15), 2010 2022. E U energy/environmental policy has at least two major and interrelated goals: to increase the p e r c e n t a g e of electricity from renewable energy sources (RES-E) and to control the emission of G H G cost efficiently. These two goals could be in conflict. This paper explores one aspect of this conflicting relationship, namely the effect that the use of the Kyoto Protocol project m e c h a n i s m s ( C D M / J I project) may have on the d e p l o y m e n t of R E S - E within E U borders. The main conclusion is that, under certain assumptions (i.e. no m a n d a t o r y E U R E S - E quota), C D M / J I projects m i g h t reduce the incentive to deploy R E S - E within E U borders because they would allow E u r o p e a n power companies to comply with G H G targets in a cheaper way than if they reduced emissions by investing in renewable electricity in Europe. This is problematic, since many benefits from renewable electricity are local and these would be gone. This situation would be different if a m a n d a t o r y R E S - E q u o t a (combined with an EU-wide TGC scheme) was implemented. In this case, the R E S - E target would be fulfilled and C D M / J I projects would only affect R E S - E d e p l o y m e n t exceeding the target.
06/00704 Transfer of transient surge voltage through XLPE cable winding transformer (Dryformer) circuits Manyahi, M. J. et al. International Journal of Electrical Power & Energy Systems, 2005, 27, (8), 602 609. E x p e r i m e n t and simulation results of conventional transformer design have shown that there are considerable differences in the characteristics of the surge voltages that are i m p o r t a n t in deciding the transferred voltages, d e p e n d i n g on w h e t h e r it is from primary to secondary or vice versa. Dryformer is a new technological advance of dry power transformer, which is constructed from X L P E insulated high voltage cables as its winding, and is designed to provide a direct link between ultimate customers and transmission systems in one step transformation. It is i m p o r t a n t therefore to have a b e t t e r understanding of Dryformer behaviour in regard to transient surge voltage transfer between its circuits. This p a p e r presents the application of a high frequency m o d e l for the study of transient surge voltage transfer between the Dryformer circuits due to surges having various steepness, a m p l i t u d e and duration characteristics, which are expected in practise. The model is based on the creation of an R L C G network that gives the same a d m i t t a n c e function as that obtained experimentally at the transformer terminals. The validity of the f o r m u l a t e d model has been verified by comparing the model predictions with experimentally obtained voltage transfer function. The m o d e l is successfully applied in estimating the t h r e a t levels posed to Dryformer winding and customer connected e q u i p m e n t due to transient overvoltages.
06/00705 Transmission congestion management in bilateral markets: an interruptible load auction solution Tuan, L. A. et al. Electric Power Systems Research, 2005, 74, (3), 379 389. This paper d e m o n s t r a t e s that a p p r o p r i a t e invocation of interruptible loads by the i n d e p e n d e n t system operator (ISO) can aid in relieving transmission congestion in power systems. A n auction m o d e l is proposed, for an ISO operating in a bilateral contract d o m i n a t e d market, for real-time selection of interruptible load offers while satisfying the congestion m a n a g e m e n t objective. The proposed congestion m a n a g e m e n t scheme using interruptible loads can specifically identify load buses where corrective measures are n e e d e d for relieving congestion on a particular transmission corridor. The N 1 contingency criterion has been taken into account to simulate various cases, and hence, examine the effectiveness of the proposed method. It has been shown that the m e t h o d can assist the ISO to remove the overload from lines in both n o r m a l and contingency conditions in an o p t i m a l manner.
Fuel and Energy Abstracts
March 2006
105