| 1. |
- Ali, Muhammad Taha, et al.
(författare)
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Mitigation of Sub-Synchronous Control Interaction in DFIGs using a Power Oscillation Damper
- 2017
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Ingår i: 2017 IEEE Manchester PowerTech, Powertech 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- The aim of this research work is to analyse subsynchronous control interaction (SSCI) in doubly-fed induction generators (DFIGs) and to design a supplementary control technique for the mitigation of SSCI. A mathematical model of the DFIG is derived and linearized in order to perform an eigenvalue analysis. This analysis pinpoints the parameters of the system which are sensitive in making sub-synchronous modes unstable and hence are responsible for causing SSCI. A power oscillation damper (POD) is designed using a residue method to make the DFIG system immune to the SSCI. The POD control signal acts as a supplementary control, which is fed to the controller of the grid-side converter (GSC). The POD signal is applied to different summation junctions of the GSC controller in order to determine the best placement of the POD for effective mitigation of SSCI and for the increased damping of the system.
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| 2. |
- Alvarez Perez, Manuel Alejandro, 1980-, et al.
(författare)
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A Hydro-Reservoir Generic Storage Model for Short-Term Hydrothermal Coordination
- 2017
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Ingår i: IEEE PES PowerTech Manchester 2017: towards and beyond sustainable energy systems, 2017. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- This work presents a linear solution for the short-term hydro-thermal scheduling problem linked to long-term conditions through a piecewise-linear Future Cost Function (FCF). Given end-point conditions to conform long-term water releases, and given actual reservoir conditions, a segment of a pre-built piecewise future cost function will be chosen. The linear characteristic of the FCF segment will allow a linear modeling of the hydro-power plant, in a similar fashion as a thermal unit with an equivalent marginal opportunity cost. A short-term hydro thermal coordination problem will be formulated considering parallel and cascaded hydro-reservoirs. Three study cases involving different reservoir configurations and scenarios will be computed to test the model. The results of this model mimics coherently the future-cost hydro-thermal coordination problem for the different configurations tested. Given similarities with other forms of energy storage, a new theoretical model for generic storage will be proposed and discussed.
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| 3. |
- Alvarez Perez, Manuel Alejandro, 1980-, et al.
(författare)
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Remuneration Assessment of a VPP Providing Distribution Capacity Services
- 2017
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Ingår i: IEEE PES PowerTech Manchester 2017. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- A Distribution System Operator (DSO) might consider a capacity contract as a planning alternative to defer grid investments. A Virtual Power Plant (VPP) might be able to provide such capacity and change its production as requested by the DSO. This article presents an assessment of the impact of this type of distribution capacity contract (DCC) on VPP's remuneration. This assessment is done by comparing the optimal production / bidding strategy which maximize its profit, under presence or absence of these contracts. The impact of intermittent generation and storage while evaluating these scenarios will be investigated as well. A stochastic unit commitment will be used to determine the VPP's strategy under uncertainties from wind power, load, market prices, and the requested power by the DSO. The model showed that the VPP involvement in distribution capacity contracts can improve its remuneration when certain types of Distributed Energy Resources (DER) are used to provide the service.
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| 4. |
- Babazadeh, Davood, et al.
(författare)
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Distributed Two-stage Network Topology Processor for HVDC Grid Operation
- 2017
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Ingår i: 2017 IEEE Manchester PowerTech, Powertech 2017. - : IEEE. - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- This paper presents the results of an analysis of distributed two-stage coordination of network topology processor for HVDC grids. In the first stage of the two-stage processor, the substation topology is analyzed locally using an automated graph-based algorithm. Thereafter, a distributed algorithm is proposed to used the neighboring information to realize the grid connectivity. For distributed islanding detection, the connectivity problem is formulated as a set of linear equations and solved iteratively using successive-over-relaxation method. The performance of the proposed methods versus conventional one-stage method has been tested in an islanding scenario for a 5-terminal HVDC grid.
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| 5. |
- Barakou, Fani, et al.
(författare)
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Downstream network modeling for switching transients in EHV networks containing cables
- 2017
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Ingår i: IEEE PES PowerTech Manchester 2017: towards and beyond sustainable energy systems, 2017. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- For the study of switching transients in Extra High Voltage (EHV) networks it is common practice to model a relatively small part of the EHV network. The downstream network is either disregarded or modeled as a parallel RC or RL circuit, based on the powerflow, directly at the secondary side of the transmission transformer. In this paper an investigation for the extent and model type of the downstream network (below 380 kV) is performed. A detailed model for an example downstream network is developed. Different simplifications and equivalent models are compared in frequency domain and in time domain, during cable energization. The impact of the lower voltage network on both the maximum overvoltage and the harmonic content during energization is assessed. Moreover, components that are of major importance are identified and proper equivalent models for the downstream network are proposed. Simulation results show that in particular the type of the 150 kV network (underground cable or overhead line) affects greatly both the maximum overvoltage and the harmonic content during energization. On the other hand, the parameters of end customer loads have only minor effect.
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| 6. |
- Cadenovic, Rade, et al.
(författare)
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Optimal reconfiguration of distribution network using cycle-break/genetic algorithm
- 2017
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Ingår i: 2017 IEEE Manchester PowerTech, Powertech 2017; Manchester; United Kingdom; 18 June 2017 through 22 June 2017. - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- This paper presents novel approach for optimal distribution network reconfiguration using the combination of cycle-break algorithm and genetic algorithms. Significant improvements are introduced in the phases of initial population generation as well as other general operations inside genetic algorithm. These improvements lead to better convergence rate and computational time reduction. Even though genetic algorithms are widely used, problems related to inapplicability for real-size are often present. These problems are related to the high individual rejection rate due to violation of system constraints and distribution network radial structure requirements. Utilization of combined cycle-break algorithm and genetic algorithm solves these issues and allow real-size network application. Acknowledging this fact, algorithm described in the paper is used to find optimal distribution network topology while fulfilling system constraints and maintaining radial network requirements in all solution steps. The proposed algorithm for optimal distribution network reconfiguration is tested on several standard IEEE test cases. Optimal distribution network reconfiguration can be found under minimum network loss or optimal network loading framework.
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| 7. |
- Göransson, Martin, 1991, et al.
(författare)
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Cost-benefit analysis of battery storage investment for microgrid of Chalmers university campus using OPF framework
- 2017
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Ingår i: 2017 IEEE Manchester PowerTech, Powertech 2017; Manchester; United Kingdom; 18 June 2017 through 22 June 2017. - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- This paper presents a cost-benefit approach for evaluation of battery energy storage (BES) options to be installed in the electrical distribution grid of Chalmers University from the microgrid perspective. The evaluation is based on a multiperiod ac optimal power flow model applied for microgrid, which is referred to as the micro-OPF, with the objective function being the total grid operation cost. The model is developed for the real 12 kV grid of Chalmers. The micro-OPF is used as the calculation tool for the cost-benefit analysis where the benefit-to-cost ratios (BCR) of battery options in the grid in a year over the annualized cost of battery are evaluated for various options of battery sizes in the grid. The best location for the battery storage was however determined with the minimum loss criterion. The BCRs demonstrate the cost-effectiveness of the battery in microgrid operation. Battery options considered include both distributed option and a centralized option. It has been found that the best location of battery storage at Chalmers grid is at the point of connection to upstream grid of Gothenburg Energy distribution system for the centralized option. The study results show that the benefit gained from using battery storage increases with the size of battery, and the size with the highest BCR was found to be 2 MWh when considering the grid-connected mode of operation. The optimal size when the grid is in island mode is however dependent on island mode capability.
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| 8. |
- Herre, Lars, 1990-, et al.
(författare)
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Enhancing market access of demand response through generation forecast updates
- 2017
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Ingår i: 2017 IEEE Manchester PowerTech, Powertech 2017. - : IEEE. - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- Advances in communication infrastructure and elec-tric appliances have enabled demand side participation in powersystem operation. However, the full potential of demand flexibilityis yet to be exploited. Existing demand response programs requireflexibility in a set time frame from the electricity consumers inreaction to economic incentives. For a more detailed qualitativeanalysis of consumer flexibility, not only price but also noticetime are imperative parameters. The former has been studied innumerous references whereas the impact of the latter has not yetbeen examined in depth. This paper presents a market modelof demand response that enhances an efficient use of flexibleconsumers by hourly updates. The consequences of flexibleelectricity consumers are studied in a Real Time Pricing modelwith continuous forecast updates, where elasticity is subject tonotice time. A case study is presented using data from Sweden.We conclude that current demand response programs are notoptimally designed to integrate consumer flexibility that changeswith the notice time.
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| 9. |
- Hooshyar, Hossein, et al.
(författare)
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Synchrophasor applications facilitating interactions in transmission and distribution operations
- 2017
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Ingår i: 2017 IEEE Manchester PowerTech, Powertech 2017. - : IEEE. - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- Dynamics of distribution grids are becoming more and more complex to analyze due to their transition from passive networks to active ones. This has necessitated the increase of observability between Transmission and Distribution (T&D) grids for operational security and real-time security assessment. This paper presents an overview of the IDE4L project, funded by the European Commission, where a system of PMU data-based monitoring applications has been developed to facilitate TSO-DSO interactions.
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| 10. |
- Risberg, Daniel, et al.
(författare)
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Hydro Power Equivalents of Complex River Systems
- 2017
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Ingår i: 2017 IEEE Manchester PowerTech, Powertech 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509042371
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Konferensbidrag (refereegranskat)abstract
- When a hydro power producer wants to plan the production for the next day in an optimal way a precise and detailed model is needed. But when using this model to plan for a longer period of time the computational complexity increases. To overcome this problem there is a need to do a model reduction of the original system into a smaller equivalent system with almost the same properties. This paper compares the performance and computation time of different setups in the equivalent representation of the original hydro power system. This includes different setups in both topology and the piecewise linear production equivalents. It is tested independently on two rivers with 21 and 28 stations respectively and also for the case if both of these rivers were to represented by one equivalent system. The performance is evaluated with respect to error in production and computation time. It is shown that with model reduction the relative error lies between 11.5 and 5.1 percent of installed capacity and the computation time is then reduced by 99.3 and 92.5 percent respectively.
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