http://hdl.handle.net/2117/3862 Sun, 19 May 2013 09:18:38 GMT 2013-05-19T09:18:38Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://hdl.handle.net/2117/18728 Title: Control of Full-Scale Converter based Wind Power Plants for damping of low frequency system oscillations Authors: Rodríguez Cortés, Pedro; Teodorescu, Remus; Adamczyk, Andrzej Grzegorz Abstract: Damping of low frequency power oscillations is one of essential aspects of maintaining power system stability. In literature can be found publications on damping capability of Doubly Fed Induction Generator based wind turbines. This paper extends discussion on Wind Power Plant damping capability to Full-Scale Converter based type. Moreover resemblance of such Wind Power Plant to modern FACTS devices is recognized and exploited. Paper discusses many aspect of damping controller design, including feedback signal selection and control effectiveness with respect to wind farm location. Analysis and design is based on modal analysis, therefore matching modeling approach for wind power plant is proposed. Finally, performance of Wind Power Plant damping control is compared to a regular power system stabilizer installed on a synchronous generator. Tue, 09 Apr 2013 10:56:01 GMT http://hdl.handle.net/2117/18728 2013-04-09T10:56:01Z Rodríguez Cortés, Pedro; Teodorescu, Remus; Adamczyk, Andrzej Grzegorz no Damping of low frequency power oscillations is one of essential aspects of maintaining power system stability. In literature can be found publications on damping capability of Doubly Fed Induction Generator based wind turbines. This paper extends discussion on Wind Power Plant damping capability to Full-Scale Converter based type. Moreover resemblance of such Wind Power Plant to modern FACTS devices is recognized and exploited. Paper discusses many aspect of damping controller design, including feedback signal selection and control effectiveness with respect to wind farm location. Analysis and design is based on modal analysis, therefore matching modeling approach for wind power plant is proposed. Finally, performance of Wind Power Plant damping control is compared to a regular power system stabilizer installed on a synchronous generator. http://hdl.handle.net/2117/18713 Title: Var reserve concept applied to a wind power plant Authors: Martinez, J.; Kjaer, Philip Carne; Rodríguez Cortés, Pedro; Teodorescu, Remus Abstract: wind power plants. This paper proposes two different VAr reserve control strategies for a wind power plant. The amount of dynamic VAr available most of the operation time, makes the wind power plant (WPP) a good candidate to include a VAr reserve management system. Two different ways of implementing a VAr management system are proposed and analyzed. Tue, 09 Apr 2013 07:36:56 GMT http://hdl.handle.net/2117/18713 2013-04-09T07:36:56Z Martinez, J.; Kjaer, Philip Carne; Rodríguez Cortés, Pedro; Teodorescu, Remus no wind power plants. This paper proposes two different VAr reserve control strategies for a wind power plant. The amount of dynamic VAr available most of the operation time, makes the wind power plant (WPP) a good candidate to include a VAr reserve management system. Two different ways of implementing a VAr management system are proposed and analyzed. http://hdl.handle.net/2117/18500 Title: Storage possibilities for enabling higher wind energy penetration Authors: Swierczynski, M.; Teodorescu, Remus; Rasmunssen, C. N.; Rodríguez Cortés, Pedro; Vikelgaard, H. Abstract: As the installed worldwide wind energy capacity increases about 30% annually and Kyoto protocol that came in force in 2005, wind penetration level in power system is considered to significantly increase in near future. Due to increased penetration and nature of the wind, especially its intermittency, partly unpredictability and variability, wind power can put the operation of power system into risk. One of the possible solutions can be an addition of energy storage into wind power plant. This paper deals with state of the art of the Energy Storage (ES) technologies and their possibility of accommodation for wind turbines. Overview of ES technologies is done in respect to its suitability for Wind Power Plant (WPP). Services that energy storage can offer both to WPP and power system are discussed. Moreover examples of already existing installations are shown Fri, 22 Mar 2013 13:22:43 GMT http://hdl.handle.net/2117/18500 2013-03-22T13:22:43Z Swierczynski, M.; Teodorescu, Remus; Rasmunssen, C. N.; Rodríguez Cortés, Pedro; Vikelgaard, H. no As the installed worldwide wind energy capacity increases about 30% annually and Kyoto protocol that came in force in 2005, wind penetration level in power system is considered to significantly increase in near future. Due to increased penetration and nature of the wind, especially its intermittency, partly unpredictability and variability, wind power can put the operation of power system into risk. One of the possible solutions can be an addition of energy storage into wind power plant. This paper deals with state of the art of the Energy Storage (ES) technologies and their possibility of accommodation for wind turbines. Overview of ES technologies is done in respect to its suitability for Wind Power Plant (WPP). Services that energy storage can offer both to WPP and power system are discussed. Moreover examples of already existing installations are shown http://hdl.handle.net/2117/18400 Title: Smart - STATCOM control strategy implementation in wind power plants Authors: Sintamarean, Craiun; Cantarellas, A.; Miranda, Hernan; Rodríguez Cortés, Pedro; Teodorescu, Remus Abstract: High penetration of wind energy into the grid may introduce stability and power quality problems due to the fluctuating nature of the wind and the increasing complexity of the power system. By implementing advanced functionalities in power converters, it is possible to improve the performance of the wind farm and also to provide grid support, as it is required by the grid codes. One of the main compliance difficulties that can be found in such power plants are related to reactive power compensation and to keep the harmonics content between the allowed limits, even if the power of the WPP converters is increasing. This paper deals with an advanced control strategy design of a three-level converter performing STATCOM and Active Filter functionalities. The proposed system is called Smart-STATCOM since it has the capability of self-controlling reactive power and harmonic voltages at the same time. Therefore, deciding the amount of non-active currents (fundamental, 5th and 7th harmonics) to be injected depending on the PCC voltage quality. Experimental results of the proposed control strategy are analyzed in order to validate the performance of the entire system. Keywords- STATCOM, Active Filter, Power Quality Tue, 19 Mar 2013 12:40:33 GMT http://hdl.handle.net/2117/18400 2013-03-19T12:40:33Z Sintamarean, Craiun; Cantarellas, A.; Miranda, Hernan; Rodríguez Cortés, Pedro; Teodorescu, Remus no High penetration of wind energy into the grid may introduce stability and power quality problems due to the fluctuating nature of the wind and the increasing complexity of the power system. By implementing advanced functionalities in power converters, it is possible to improve the performance of the wind farm and also to provide grid support, as it is required by the grid codes. One of the main compliance difficulties that can be found in such power plants are related to reactive power compensation and to keep the harmonics content between the allowed limits, even if the power of the WPP converters is increasing. This paper deals with an advanced control strategy design of a three-level converter performing STATCOM and Active Filter functionalities. The proposed system is called Smart-STATCOM since it has the capability of self-controlling reactive power and harmonic voltages at the same time. Therefore, deciding the amount of non-active currents (fundamental, 5th and 7th harmonics) to be injected depending on the PCC voltage quality. Experimental results of the proposed control strategy are analyzed in order to validate the performance of the entire system. Keywords- STATCOM, Active Filter, Power Quality http://hdl.handle.net/2117/18351 Title: Study on harmonic resonances and damping in wind power plant Authors: Md. Hasan, Khairul Nisak; Rauma, Kalle; Luna Alloza, Álvaro; Candela García, José Ignacio; Rodríguez Cortés, Pedro Abstract: Harmonic resonance is among imperative aspect need to be analyzed in a wind power plant (WPP). It becomes complex since it involves a large network with high operating power. This paper presents a study on harmonic resonances in a WPP, particularly on parallel resonance. Important factors including length of cable, number of operating wind turbine and usage of output grid-side filter are analyzed. The damping of resonance by using common passive filter and an alternative hybrid filter is also explored. An aggregated WPP model of 400 MW with 40 wind turbines of 10 MW each are used as a study case Fri, 15 Mar 2013 13:01:03 GMT http://hdl.handle.net/2117/18351 2013-03-15T13:01:03Z Md. Hasan, Khairul Nisak; Rauma, Kalle; Luna Alloza, Álvaro; Candela García, José Ignacio; Rodríguez Cortés, Pedro no Harmonic resonance, Hybrid filter, wind power plant Harmonic resonance is among imperative aspect need to be analyzed in a wind power plant (WPP). It becomes complex since it involves a large network with high operating power. This paper presents a study on harmonic resonances in a WPP, particularly on parallel resonance. Important factors including length of cable, number of operating wind turbine and usage of output grid-side filter are analyzed. The damping of resonance by using common passive filter and an alternative hybrid filter is also explored. An aggregated WPP model of 400 MW with 40 wind turbines of 10 MW each are used as a study case http://hdl.handle.net/2117/18347 Title: PSO based optimal output feedback controller for two-area LFC system Authors: Rakhshani, Elyas; Luna Alloza, Álvaro; Sadeh, J.; Rodríguez Cortés, Pedro Abstract: A new combined method based on optimal control is proposed to enhance load frequency control dynamics. This method include of PSO and optimal output feedback controller. In the output feedback method only the measurable state variables within each control area is required to use for feedback. The optimal control law is determined by minimizing a performance index under the output feedback conditions leading to a coupled matrix equation. But for more accuracy and better design for this controller, PSO algorithm is applied to find the gain matrix of the controller. The results of the simulation are shown that with using this method, the load frequency control requirements in a practical environment are satisfied and also better dynamic responses are accessible Fri, 15 Mar 2013 11:51:51 GMT http://hdl.handle.net/2117/18347 2013-03-15T11:51:51Z Rakhshani, Elyas; Luna Alloza, Álvaro; Sadeh, J.; Rodríguez Cortés, Pedro no A new combined method based on optimal control is proposed to enhance load frequency control dynamics. This method include of PSO and optimal output feedback controller. In the output feedback method only the measurable state variables within each control area is required to use for feedback. The optimal control law is determined by minimizing a performance index under the output feedback conditions leading to a coupled matrix equation. But for more accuracy and better design for this controller, PSO algorithm is applied to find the gain matrix of the controller. The results of the simulation are shown that with using this method, the load frequency control requirements in a practical environment are satisfied and also better dynamic responses are accessible http://hdl.handle.net/2117/18281 Title: Enhanced average current-mode control for DC-DC converters based on an optimized fuzzy logic controller Authors: Rouzbehi, Kumars; Miranian, Arash; Citro, Costantino; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro Abstract: This paper proposes a novel optimized fuzzy logic controller (OFLC) for current-mode control (CMC)-based voltage regulation in DC-DC converters. The implementation of the proposed fuzzy logic controller (FLC) does not depend on the mathematical model of the converter and only requires knowledge about its operation modes. The fast and efficient algorithm of particle swarm optimization (PSO) has been employed to enhance the performance of the FLC by fine tuning its membership functions. The reference current for the current control loop has been obtained in the outer voltage loop by measuring load current and output voltage and calculating the load resistive impedance. The proposed OFLC has been used in four different case studies for evaluating its performance under different conditions of input voltage and load variations as well as variations in the system parameters, e.g. inductance and capacitance of the converter circuit. The results of simulations and comparison to a proportional-integral (PI) controller demonstrates the fast and robust performance of the proposed controller, able to effectively regulate the output voltage in presence of high perturbations in the input voltage and high variation of the converter components nominal values Wed, 13 Mar 2013 16:43:23 GMT http://hdl.handle.net/2117/18281 2013-03-13T16:43:23Z Rouzbehi, Kumars; Miranian, Arash; Citro, Costantino; Luna Alloza, Álvaro; Rodríguez Cortés, Pedro no This paper proposes a novel optimized fuzzy logic controller (OFLC) for current-mode control (CMC)-based voltage regulation in DC-DC converters. The implementation of the proposed fuzzy logic controller (FLC) does not depend on the mathematical model of the converter and only requires knowledge about its operation modes. The fast and efficient algorithm of particle swarm optimization (PSO) has been employed to enhance the performance of the FLC by fine tuning its membership functions. The reference current for the current control loop has been obtained in the outer voltage loop by measuring load current and output voltage and calculating the load resistive impedance. The proposed OFLC has been used in four different case studies for evaluating its performance under different conditions of input voltage and load variations as well as variations in the system parameters, e.g. inductance and capacitance of the converter circuit. The results of simulations and comparison to a proportional-integral (PI) controller demonstrates the fast and robust performance of the proposed controller, able to effectively regulate the output voltage in presence of high perturbations in the input voltage and high variation of the converter components nominal values http://hdl.handle.net/2117/18053 Title: Dielectric, mechanical, and thermal characterization of high-density polyethylene composites with ground tire rubber Authors: Mujal Rosas, Ramón María; Marín Genescá, Marcos; Orrit Prat, Jordi; Rahhali, Ahmed; Colom Fajula, Xavier Abstract: The mass manufacture of tires and the difficulty in storing or disposing them constitute a serious environmental problem. At present, various recycling methods for tires are used, such as grinding, which separates the steel and fibers from the vulcanized rubber, then using the rubber in numerous industrial applications such as pavements, insulators, footwear, etc. The aim of this article focuses on finding a new application for the ground tire rubber (GTR). This would allow including GTR in industrial applications of recycled high-density polythene (HDPE). Tire dust and HDPE thermoplastic have been mixed, and the maximum accepted values of GTR concentration that can be admitted while keeping dielectric, mechanical, and thermal properties within acceptable values, as well as initial polymer microstructure, have been checked. In addition, the suitability of the compounds for antistatic applications is studied. The recycled tire dust which results from the industrial milling processes has been divided by sieve in three different categories according to the size of the particles (<200, 200–500, and >500 mm). This has then been mixed with HDPE in different GTR concentrations (0%, 5%, 10%, 20%, 40%, 50%, and 70%) in order to establish its conduct through electrical, mechanical, thermal, and microstructure tests, which will be held in a temperature range 30–120_C, and with a frequency range 1 _ 10_2 and 3 _ 106 Hz. The thermal tests determined the enthalpies and fusion temperatures which allow for the observation of changes in crystalline and microstructure of the matrix, and finally, the fracture surfaces of the compound samples have been evaluated using scanning electron microscopy Tue, 05 Mar 2013 10:41:14 GMT http://hdl.handle.net/2117/18053 2013-03-05T10:41:14Z Mujal Rosas, Ramón María; Marín Genescá, Marcos; Orrit Prat, Jordi; Rahhali, Ahmed; Colom Fajula, Xavier no The mass manufacture of tires and the difficulty in storing or disposing them constitute a serious environmental problem. At present, various recycling methods for tires are used, such as grinding, which separates the steel and fibers from the vulcanized rubber, then using the rubber in numerous industrial applications such as pavements, insulators, footwear, etc. The aim of this article focuses on finding a new application for the ground tire rubber (GTR). This would allow including GTR in industrial applications of recycled high-density polythene (HDPE). Tire dust and HDPE thermoplastic have been mixed, and the maximum accepted values of GTR concentration that can be admitted while keeping dielectric, mechanical, and thermal properties within acceptable values, as well as initial polymer microstructure, have been checked. In addition, the suitability of the compounds for antistatic applications is studied. The recycled tire dust which results from the industrial milling processes has been divided by sieve in three different categories according to the size of the particles (<200, 200–500, and >500 mm). This has then been mixed with HDPE in different GTR concentrations (0%, 5%, 10%, 20%, 40%, 50%, and 70%) in order to establish its conduct through electrical, mechanical, thermal, and microstructure tests, which will be held in a temperature range 30–120_C, and with a frequency range 1 _ 10_2 and 3 _ 106 Hz. The thermal tests determined the enthalpies and fusion temperatures which allow for the observation of changes in crystalline and microstructure of the matrix, and finally, the fracture surfaces of the compound samples have been evaluated using scanning electron microscopy http://hdl.handle.net/2117/17636 Title: Study on dielectric, mechanical and thermal properties of polypropylene (PP) composites with ground tyre rubber (GTR) Authors: Mujal Rosas, Ramón María; Orrit Prat, Jordi; Ramis Juan, Xavier; Marín Genescá, Marcos; Rahhali, Ahmed Mon, 11 Feb 2013 14:57:40 GMT http://hdl.handle.net/2117/17636 2013-02-11T14:57:40Z Mujal Rosas, Ramón María; Orrit Prat, Jordi; Ramis Juan, Xavier; Marín Genescá, Marcos; Rahhali, Ahmed no Recycling rubber, PP/GTR composite, Dielectric properties, Mechanical properties, Thermal properties, Microstructure analysis http://hdl.handle.net/2117/17612 Title: Aplicaciones eléctricas del acrilonitrilo butadieno estireno (ABS) reforzado con neumáticos fuera de uso (GTR) Authors: Mujal Rosas, Ramón María; Orrit Prat, Jordi; Ramis Juan, Xavier; Marín Genescá, Marcos Fri, 08 Feb 2013 13:57:52 GMT http://hdl.handle.net/2117/17612 2013-02-08T13:57:52Z Mujal Rosas, Ramón María; Orrit Prat, Jordi; Ramis Juan, Xavier; Marín Genescá, Marcos no http://hdl.handle.net/2117/17502 Title: Wind power plant control: an overview Authors: Altin, Müfit; Teodorescu, Remus; Bak-Jensen, Birgitte; Rodríguez Cortés, Pedro; Iov, Florin; Kjaer, Philip Carne Abstract: Recent developments in wind turbine technology go towards installation of larger Wind Power Plants (WPPs). Therefore, power system operators have been challenged by the WPP penetration impacts in order to maintain reliabillity and stability of the power system. The revised grid codes have concentrated on the WPP connection point and as a result a WPP is considered as a single power plant. Nevertheless, compared to conventional power plants, WPPs have different inherent features such as converter-based grid interface technology, internal electrical layout, and asynchronous operation of turbines. Talking these into account, a WPP controller is the key factor in order to satisfy the grid code requirements. This paper presents a comprehensive overview of various WPP controller strategies comprising active power, reactive power, voltage, frequency, and emulated inertia control. The WPP control architecture composed of WPP control level and wind turbine control level is also discussed considering the hierearchy and coordination of these levels. Wed, 23 Jan 2013 14:47:55 GMT http://hdl.handle.net/2117/17502 2013-01-23T14:47:55Z Altin, Müfit; Teodorescu, Remus; Bak-Jensen, Birgitte; Rodríguez Cortés, Pedro; Iov, Florin; Kjaer, Philip Carne no Recent developments in wind turbine technology go towards installation of larger Wind Power Plants (WPPs). Therefore, power system operators have been challenged by the WPP penetration impacts in order to maintain reliabillity and stability of the power system. The revised grid codes have concentrated on the WPP connection point and as a result a WPP is considered as a single power plant. Nevertheless, compared to conventional power plants, WPPs have different inherent features such as converter-based grid interface technology, internal electrical layout, and asynchronous operation of turbines. Talking these into account, a WPP controller is the key factor in order to satisfy the grid code requirements. This paper presents a comprehensive overview of various WPP controller strategies comprising active power, reactive power, voltage, frequency, and emulated inertia control. The WPP control architecture composed of WPP control level and wind turbine control level is also discussed considering the hierearchy and coordination of these levels. http://hdl.handle.net/2117/17437 Title: FACTS Devices for large wind power plants Authors: Adamczyk, A.; Teodorescu, Remus; Mukerjee, R. N.; Rodríguez Cortés, Pedro Abstract: Growing number of wind turbines is changing electricity generation profile all over the world. However, high wind energy penetration affects power system safety and stability. For this reason transmission system operators (TSO) impose more stringent connection requirements on the wind power plant (WPP) owners. On the other hand flexible AC transmission systems (FACTS) devices offer enhancement of grid stability and can facilitate grid code compliance for WPP. In this paper state-of-the-art in FACTS for large WPPs with AC connection is given. FACTS devices (excluding HVDC) with their properties are described. Academic and industrial research in FACTS applicability for WPPs is summarized Mon, 21 Jan 2013 13:35:06 GMT http://hdl.handle.net/2117/17437 2013-01-21T13:35:06Z Adamczyk, A.; Teodorescu, Remus; Mukerjee, R. N.; Rodríguez Cortés, Pedro no Growing number of wind turbines is changing electricity generation profile all over the world. However, high wind energy penetration affects power system safety and stability. For this reason transmission system operators (TSO) impose more stringent connection requirements on the wind power plant (WPP) owners. On the other hand flexible AC transmission systems (FACTS) devices offer enhancement of grid stability and can facilitate grid code compliance for WPP. In this paper state-of-the-art in FACTS for large WPPs with AC connection is given. FACTS devices (excluding HVDC) with their properties are described. Academic and industrial research in FACTS applicability for WPPs is summarized http://hdl.handle.net/2117/17418 Title: Application of over-current relay in offshore wind power plant grid with VSC-HVDC connection Authors: Chaudhary, S. K.; Teodorescu, Remus; Rodríguez Cortés, Pedro; Kjaer, Philip Carne Abstract: This paper presents the setting and coordination of over-current relays in an offshore wind power plant (WPP) grid connected only to the power electronic converters with limited fault current capability. The limited fault current injection capability of the converters has been considered as a hindrance for the relay setting. This characteristic can be utilized to develop a deterministic picture of the radial grid network and then the relays settings could be applied. The relay coordination has been demonstrated through an implementation in the Real Time Digital Simulator (RTDS) platform. The setting of relay parameters based upon maximum nominal currents is explained and the consequences are investigated. Fri, 18 Jan 2013 10:41:07 GMT http://hdl.handle.net/2117/17418 2013-01-18T10:41:07Z Chaudhary, S. K.; Teodorescu, Remus; Rodríguez Cortés, Pedro; Kjaer, Philip Carne no This paper presents the setting and coordination of over-current relays in an offshore wind power plant (WPP) grid connected only to the power electronic converters with limited fault current capability. The limited fault current injection capability of the converters has been considered as a hindrance for the relay setting. This characteristic can be utilized to develop a deterministic picture of the radial grid network and then the relays settings could be applied. The relay coordination has been demonstrated through an implementation in the Real Time Digital Simulator (RTDS) platform. The setting of relay parameters based upon maximum nominal currents is explained and the consequences are investigated. http://hdl.handle.net/2117/17281 Title: Enhanced decoupled double synchronous reference frame current controller for unbalanced grid-voltage conditions Authors: Reyes, M.; Rodríguez Cortés, Pedro; Vazquez, S.; Luna Alloza, Álvaro; Teodorescu, Remus; Carrasco, J.M. Abstract: In the last few years, restrictive grid codes have arisen to ensure the performance and stability of electrical networks, which experience amassive integration of renewable energy sources and distributed generation systems that are normally connected to the grid through electronic power converters. In these codes, the injection of positive- and negative-sequence current components becomes necessary for fulfilling, among others, the low-voltage ride-through requirements during balanced and unbalanced grid faults. However, the performance of classical dq current controllers, applied to power converters, under unbalanced grid-voltage conditions is highly deficient, due to the unavoidable appearance of current oscillations. This paper analyzes the performance of the double synchronous reference frame controller and improves its structure by adding a decoupling network for estimating and compensating the undesirable current oscillations. Experimental results will demonstrate the validity of the proposed decoupled DSRF controller Fri, 11 Jan 2013 13:57:37 GMT http://hdl.handle.net/2117/17281 2013-01-11T13:57:37Z Reyes, M.; Rodríguez Cortés, Pedro; Vazquez, S.; Luna Alloza, Álvaro; Teodorescu, Remus; Carrasco, J.M. no AC-DC power conversion, current control, power electronics In the last few years, restrictive grid codes have arisen to ensure the performance and stability of electrical networks, which experience amassive integration of renewable energy sources and distributed generation systems that are normally connected to the grid through electronic power converters. In these codes, the injection of positive- and negative-sequence current components becomes necessary for fulfilling, among others, the low-voltage ride-through requirements during balanced and unbalanced grid faults. However, the performance of classical dq current controllers, applied to power converters, under unbalanced grid-voltage conditions is highly deficient, due to the unavoidable appearance of current oscillations. This paper analyzes the performance of the double synchronous reference frame controller and improves its structure by adding a decoupling network for estimating and compensating the undesirable current oscillations. Experimental results will demonstrate the validity of the proposed decoupled DSRF controller http://hdl.handle.net/2117/17279 Title: Effect of VSC-HVDC on load frequency control in multi-area power system Authors: Rakhshani, Elyas; Luna Alloza, Álvaro; Rouzbehi, Kumars; Rodríguez Cortés, Pedro; Etxeberria Otadui, Ion Abstract: This study presents a solution for reducing the frequency oscillations in multi-area interconnected power system by means of using an VSC-HVDC interconnection transmission line. The upcoming power-electronics based HVDC transmission system offers new features that can be advantageous for improving the frequency control and thus for enhancing the stability in transmission networks. This paper is structured in two main parts; the first one is be devoted to introduce the basic elements of HVDC links and the second part will be focused on the effects of the HVDC links in the frequency control of interconnected power systems. In order to show the positive effects of HVDC links under random load disturbance, a model with parallel AC-DC interconnected power system, including a new power modulation controller of bi-directional VSC-HVDC link, is proposed and simulated. Comparisons between HVAC and HVDC transmissions are presented and its performance is evaluated using Matlab/Simulink Fri, 11 Jan 2013 13:01:54 GMT http://hdl.handle.net/2117/17279 2013-01-11T13:01:54Z Rakhshani, Elyas; Luna Alloza, Álvaro; Rouzbehi, Kumars; Rodríguez Cortés, Pedro; Etxeberria Otadui, Ion no This study presents a solution for reducing the frequency oscillations in multi-area interconnected power system by means of using an VSC-HVDC interconnection transmission line. The upcoming power-electronics based HVDC transmission system offers new features that can be advantageous for improving the frequency control and thus for enhancing the stability in transmission networks. This paper is structured in two main parts; the first one is be devoted to introduce the basic elements of HVDC links and the second part will be focused on the effects of the HVDC links in the frequency control of interconnected power systems. In order to show the positive effects of HVDC links under random load disturbance, a model with parallel AC-DC interconnected power system, including a new power modulation controller of bi-directional VSC-HVDC link, is proposed and simulated. Comparisons between HVAC and HVDC transmissions are presented and its performance is evaluated using Matlab/Simulink