Implementation and validation of dynamic wind turbine models for grid integration
- Autores: Raquel Villena Ruiz
- Directores de la Tesis: Emilio Gómez Lázaro (dir. tes.), Andrés Honrubia Escribano (codir. tes.)
- Lectura: En la Universidad de Castilla-La Mancha ( España ) en 2020
- Idioma: español
- Tribunal Calificador de la Tesis: Olimpo Anaya Lara (presid.), Sergio Martín Martínez (secret.), Jose Luis Domínguez García (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencias y Tecnologías aplicadas a la Ingeniería Industrial por la Universidad de Castilla-La Mancha
- Materias:
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- Resumen
The spectacular growth in wind power in recent years is excellent news in the current energy context. The expansion of this type of renewable energy source worldwide, which has become one of the most reliable forms of alternative energy, has brought the total cumulative capacity installed to more than 591 GW. Within this framework, Spain is positioned second in Europe and fifth in the world in terms of installed capacity, with nearly 23 GW of wind power. This situation also explains the new daily record achieved in our country: 411 GWh were generated by wind power plants on a single day in December 2019, which represents approximately 50% of the total electricity consumption on that date.
However, the natural variability of wind, and in general of all renewable energy resources, brings some uncertainty to current power systems and affects their performance. This situation highlights the need to strengthen the network, ensuring the quality and continuity of electricity supply, as well as carefully assessing and quantifying the impact of the penetration of wind energy in power systems. In this sense, Distribution System Operators (DSO) and Transmission System Operators (TSO) in each country are the main entities entrusted with the proper operation of the grid and maintenance of its infrastructures at every level. Conducting dynamic simulations may therefore help DSOs and TSOs to predict the behavior of power systems when an increasing number of Wind Power Plants (WPP) are integrated. In this sense, the assessment of the behavior of Wind Turbines (WT) and WPPs when facing grid events, such as loss of generation or voltage dips, is particularly important.
In this regard, the first WT simulation models were developed by WT manufacturers, and are thus private, complex, very detailed and represent only one specific model of an actual WT. Faced with this situation, the International Electrotechnical Commission (IEC), through Standard IEC 61400-27-1, developed sufficiently generic WT simulation models to represent the vast majority of actual WT models within the same topology. These publicly available generic models are studied by conducting Root Mean Square (RMS) transient stability analyses and may be implemented in any simulation software tool. Moreover, in order to demonstrate the usefulness, applicability and accuracy of the generic WT models, the IEC also developed its own validation methodology.
In this context, and given the lack of scientific studies related to the validation of generic WT models using specialized software tools, the first main objective of the present Doctoral Thesis is the complete implementation, simulation and validation of the Doubly Fed Induction Generator (DFIG) WT model defined by IEC 61400-27-1 in one of the most powerful software tools in the fields of electrical engineering and power systems: DIgSILENT PowerFactoryTM (PF).
It is to be noted, also, that each country usually has its own technical requirements to be complied with by WPPs connected to the national network. In Spain, Operation Procedure (PO) 12.3 is the grid code that established the requirements for fault ride-through capability of WPPs, i.e., the response that this type of installation must have under voltage dips. In addition, a specific Procedure for Verification, Validation and Certification (PVVC) was developed, which sets out the guidelines to be followed in order for Spanish WPPs to fulfill PO 12.3 requirements. In general, the procedure to certify a wind power installation following the PVVC involves the validation of the WT simulation model corresponding to the actual WT model installed at the WPP. This implies, first, conducting different field tests on the actual WT, second, the simulation of the WT model by using the field measurements of those tests, and third, the application of the PVVC validation procedure.
In light of the above, in the same line of generic WT simulation models and given that these are able to faithfully represent the behavior of most actual WTs, the second objective of the current Doctoral Thesis is to submit, for the first time, the Type 3 or DFIG WT simulation model defined by both the IEC and the Western Electricity Coordinating Council (WECC) to the requirements established by a national grid code, Spanish PO 12.3. The PVVC validation methodology is applied to these generic WT models, and some modeling modifications are proposed to improve their behavior. These analyses allow, on the one hand, the scope of application of international IEC and WECC guidelines with regard to the generic WT models to be expanded, and on the other hand, the limitations of these to be determined.
Currently, another main concern in the wind power industry is that of the aging of WTs, given that the first WPPs were commissioned many years ago. This situation leads to several negative scenarios, such as long downtimes of the machines due to the increased number of failures, costly maintenance operations or low production of energy. Under this framework, and given that these old WPPs are located at sites with excellent wind resources, one of the most logical solutions being introduced is the replacement of old WTs with newer designs, thus allowing a WPP's energy production and power performance to be notably increased.
As a consequence, in addition to the dynamic analyses of the WT models that will be part of a repowered WPP, which will also help the owner make a decision on the matter, the estimation of the technical and the economic feasibility of the project plays a key role. However, regarding the latter point, there is a lack of scientific works related to the assessment of real repowering projects, and thus the third and final main objective of the present Doctoral Thesis consists of conducting a comprehensive techno-economic analysis of a real repowering experience carried out at the Malpica WPP, located in the northwest of Spain. Likewise, the profitability of the project is estimated, and the uncertainties affecting the performance of the WPP are assessed using a sensitivity analysis.
