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Impact Analysis of Wind Farms in the Jeju Island Power System
Abstract
This paper presents modeling and impact analysis of wind farms in Jeju island power system, which is made of wind farms, a current source-type high-voltage, direct current (HVDC) system, and thermal power plants. In this paper, four kinds of major components are modeled: a total of 88 MW wind farms, a 300 MW HVDC system, thermal power plants, and the Jeju power system load. To analyze the impact of the wind power generation to the Jeju power system, simulation is carried out for two case studies by using the PSCAD/EMTDC program. One is for the steady-state operation under different wind speed, and the other is for the transient-state operation when all wind farms are disconnected suddenly from the Jeju power grid due to the wind speed higher than the rated value. These comparative studies have been effective in accessing the impact of wind power generation on the Jeju island power system stability.
... Therefore, during the overheated development period for grid-connected renewable energy projects on a large scale at present, the impact analysis of large-scale wind power and solar power plants on the Vietnamese transmission network is studied by many researchers. Several papers are related works to this paper (Abbas et al. 2020;Ameur et al. 2019;Cheng et al. 2015;Djamel et al. 2016;Kim et al. 2011;Wu et al. 2016) as follows: ...
... A recovery of significant active power deficits caused by the wake effect via increasing hub height of wind turbines was proposed. The work (Kim et al. 2011) presented modeling and impact analysis of wind farms in Jeju island power system, which was made of wind farms, a current source-type high-voltage, direct current (HVDC) system, and thermal power plants. The paper (Djamel et al. 2016) described the behavior of a wind farm integrated into the electrical power system and the effect of this energy on the different grid parameters such as the voltage, the load flow, and the frequency. ...
Integrating wind power and solar power plants into a power system has significantly grown over the past decade and is expected to grow to unprecedented levels in the coming years. In Vietnam, much large-scale wind power and solar power plants have been built and connected to the power system in recent years. To investigate and evaluate the impact of these power plants on system power operation, the 110kV power transmission network of Binh Dinh province in Vietnam is used in this paper. In the system, the Phuong Mai 3 wind power plant with a capacity of 21MW, the Fujiwara solar power plant with a peak capacity of 50MWp, and the Cat Hiep solar power plant with a peak capacity of 49.5MWp are modeled by using the PSS/E software to simulate and analyze their impacts on power system stability of the 110kV transmission network in Binh Dinh province, Vietnam. Besides, the control strategies of these power plants are also established to investigate their impacts on the network. In addition, this paper proposes three typical scenarios for the wind power and solar power plants in the system. For each scenario, the grid's operating parameters such as voltage variations and frequency variations are acquired for analyzing and evaluating their impacts on the frequency and voltage variations of the network. The simulation results show that the 110kV power transmission network remains in a stable operation mode after the fault scenarios for the wind and solar power plants. Furthermore, these simulation results provide some guidance for the actual operation
... The South Korean Jeju Island is also an example of high wind power generation penetration. There is the goal of installing 250 MW of wind power and in 2010 88 MW of wind power generation was already installed [44]. Finally, plans for increasing the RES penetration in many islands are set by other countries as well. ...
... In February 2009 approximately 20.6% was produced by geothermal energy in Hawaii Island (Big Island) [50]. Significant geothermal power is installed in Jeju Island (South Korea) where 130.1 MW of geothermal energy contribute to the total RES generation by 15% [44]. ...
Insular electricity grids are considered to have a more fragile structure than the mainland ones due to several factors such as the lower inertia because of lower number of generation facilities connected to the system, absence or insufficient interconnection with the main grid, etc. The recent trend of integrating large portions of environmentally sustainable power generation units that have a significantly volatile nature in the generation mix (such as wind and solar energy conversion systems) within this fragile structure, poses profound challenges that need deeper and specific analysis. This study aims to provide an overview of insular power system structures and operational requirements, especially under increasing penetration of renewable energy sources. Firstly, a general evaluation of insular power systems is presented. Then, potential challenges are thoroughly discussed together with opportunities to tackle them. Future technological developments, as well as innovative applications are also given special attention. Hence, this paper contributes to the scarce literature regarding insular power systems by providing a critical overview of issues regarding their operation and possible solutions.
... The island is 73 km wide and 41 km long Island and has a wind speed of 7-8 m/s on the east and west coasts which is sufficient for power generation. 15 Therefore, the installed wind power capacity in Jeju stretched from 150 to 564 GW from 2009 to 2018. The installed solar capacity also reached 480 GW in 2018. ...
The current study's objective is to evaluate wind and solar energy and select the finest kind of energy systems having minimum levelized of energy systems by using Home Pro software for Jeju Island, the largest island in South Korea. Using Weibull and mean wind speed diagrams, the wind conditions in the initial section of this study are explained. To assess the wind potential of every area, size and form criteria are offered. It was found that two main wind directions were southeast or southwest, with southwest being more common. Finally, based on the wind conditions at each site and IEC recommendations, a set of five wind turbines that were best suited for each location were shortlisted. Each wind turbine's performance was assessed using technical criteria, that is, monthly energy production, annual energy production, and capacity factors. Similar to this, economic considerations such as the levelized cost of electricity, internal rate of return, payback period, and net present value were also made. A Hanjin model HJWT 87/2000 is best suitable for Jeju Island in the event of an off-shore wind farm, according to the findings. To explore the implications of modifying the hub height of the turbines on the economics of wind generating, a thorough economic sensitivity analysis is also included. The second section explains the solar potential of the Island. The average solar energy potential of Jeju Island is estimated to be 13.775 Mj·m ² ·day ⁻¹ . To cover the energy demand and supply gap for Jaju Island, various types of local electricity generators and batteries have been studied for finding the optimal energy system for the island.
... The potential of integrating wind and solar power in Europe using spatial optimization under various scenarios was presented in [20]. The impact analysis of wind farms in the Jeju island power system by using the PSCAD/EMTDC program was shown in [21]. Wattana and Aungyut [22] analysed the impacts of solar electricity generation on the Thai electricity industry. ...
p>The rapid integration of wind power and power solar plants into the electrical power system has caused several operation issues in recent decades. To investigate the impact of large-scale renewable power plants on the tie-line loadings of a practical power grid, the 110 kV power network of Binh Dinh province, Vietnam is utilized in this paper. This power network with and without three solar power plants (including Fujiwara plant with a peak capacity of 50 MWp, Cat Hiep plant with a peak capacity of
49.5 MWp, and Dam Tra O plant with a peak capacity of 50 MWp) and three wind power plants (including Nhon Hoi plant with a capacity of 60MW, Phuong Mai 1 plant with a capacity of 26.4 MW, and Phuong Mai
3 plant with a capacity of 20.7 MW) is modeled by using the PSS/E software to examine the tie-line loadings capacity. The simulation results showed that the tie-line loadings of the current power network increase when six renewable power plants are integrated into this network. Therefore, three different scenarios to upgrade the existing power network are proposed. The final results demonstrated the efficiency of the proposed scenarios in solving the tie-line loadings issue of the practical power network.</p
... When high-capacity renewable-energy resources or distribution-generation (DG) systems, such as OWFs, are connected to a power system, the electrical characteristics at the point of common coupling (PCC) of the connected power system can be significantly deteriorated under various operating conditions and system parameters [1], [2]. The effects of such high-capacity renewable-energy resources connected to a power system have to be deeply evaluated before practical installation. ...
Submarine cables are indispensable for offshore wind farms (OWFs) connected to a power grid. Submarine cable can cause certain degrees of impact on system performance due to its different lengths, characteristics, electrical parameters, etc. This paper employs the power-system simulation software of Power System Simulator for Engineering (PSSE) for modeling a future-scheduled OWF, i.e., a large-scale doubly-fed induction generator (DFIG)-based OWF of 200 MW, connected to Jang-Bin Distribution Substation of Taiwan Power System through five feeders, five circuit breakers, two step-up power transformers, a commercial submarine cable, and an underground cable. This paper simulates and compares the electrical quantities of the studied OWF with different operating capacities under various lengths of three types of commercial submarine cable. The transient surge peak voltages at the common bus of the OWF and the bus of Jang-Bin Distribution Substation subject to the switching of one of the five circuit breakers of the studied OWF under different lengths of the three types of commercial submarine cable are also compared using the power-system simulation software of EMTP/ATPDraw.
... To install wind turbines for power generation, it is essential to select a feasible site, typically, windy islands or mountainous areas. Jeju island has the highest average wind speed in South Korea, with an annual wind speed on the east and west coasts of about 7 m/s [3,4]. Good wind conditions have led to increasing wind power generation, and public and the Jeju Energy Corporation (JEC: Jeju island Energy Institute of Technology Corporation in Jeju Special Self-Governing Province, Jeju-city, Jeju-do, Korea) of Jeju Province projects that by 2030, offshore wind power generation will rise to 2 GW [5]. ...
In this paper, the appropriate rated power of battery energy storage system (BESS) and the operating limit capacity of wind farms are determined considering power system stability, and novel output control methods of BESS and wind turbines are proposed. The rated power of BESS is determined by correlation with the kinetic energy that can be released from wind turbines and synchronous generators when a disturbance occurs in the power system. After the appropriate rated power of BESS is determined, a novel control scheme for quickly responding to disturbances should be applied to BESS. It is important to compensate the insufficient power difference between demand and supply more quickly after a disturbance, and for this purpose, BESS output is controlled using the rate of change of frequency (ROCOF). Generally, BESS output is controlled by the frequency droop control (FDC), however if ROCOF falls below the threshold, BESS output increases sharply. Under this control for BESS, the power system’s stability can be improved and the operating limit capacity of wind farms can be increased. The operating limit capacity is determined as the smaller of technical limit and dynamic limit capacity. The technical limit capacity is calculated by the difference between the maximum power of the generators connected to the power system and the magnitude of loads, and the dynamic limit capacity is determined by considering dynamic stability of a power system frequency when the wind turbines drop out from a power system. Output of the dynamic model developed for wind turbine is based on the operating limit capacity and is controlled by blade pitch angle. To validate the effectiveness of the proposed control method, different case studies are conducted, with simulations for BESS and wind turbine using Power System Simulation for Engineering (PSS/E).
... Many research has contributes to the voltage stability of the large wind power system, such as the structural bifurcation analysis [4], the stability margin estimation [5][6], and the approaches to improve the voltage stability [7][8]. [9] analyzed the impact of wind power in the Jeju Island Power System. [3] studied the mechanism of the cascading trip-off of wind turbines and analyzes the process of the failure. ...
The integration of the large-scale wind power brings great challenge to the stability of the power grid. This paper investigates and studies the fault on May 14, 2012 of the large-scale cascading trip-off of wind turbines in North China. According to the characteristics of the voltage variation, the fault process is divided into three stages: the pre-event stage, the critical stage before cascading, and the cascading stage. The scenes in the fault are reproduced, using the full-size actual power system model. Simulation models of double-fed induction generators (DFIGs) and SVCs including protection settings and controller strategies are carefully chosen to find out the reason of voltage instability in each stage. Some voltage dynamic that have never been observed before in the faults of the same kind are analyzed in detail, and an equivalent voltage sensitive dynamic model of DFIG is proposed for the fast computation. The conclusions about the voltage dynamics are validated by the actual PMU observation evidence.
... It has been a trend in wind power generation to build a grid-connected wind farm. The location for a wind farm is usually determined by the wind speed, and therefore the wind farms are concentrated in specific areas [1]. ...
This paper presents modeling and impact analysis of Al-Mukha wind farm (MWF) on Yemen power system, which is made of thermal power plants. In this paper, four kinds of major components are modeled: a 60MW wind farm, a transmission network, thermal power plants, and the Yemen power system load. To analyze the impact of the wind power generation to the Yemen power system, simulations are carried out for two case studies by using the DIgSILENT program. The first is the case of grid impact studies: impact on thermal limits, voltage variations, and system stability, in which an aggregated model of the wind farm is used. The other is the dynamic performance of the wind farm by analyzing low-voltage ride through LVRT, harmonics and flicker impact on the basis of the detailed wind farm layout with 30 wind turbines (WTs) arranged in four stands and the external grid of 2175MVA short-circuit capacity. The simulation results show that the loading of most lines and voltage variations are slightly reduced. In addition, there is no harmful effect on the system stability and also the wind farm is capable to ride through the grid fault. Finally, it is shown that the wind farm contributes voltage and current harmonics higher than the permissible limits while the flicker levels are far below any critical values.
... Jeju island has the highest average wind speed among the all promising sites in Korea and it has the best condition for wind power generation. The wind map of Jeju island was shown in [1]. A study on wind speed prediction using artificial neural network at Jeju island in Korea was also investigated by the authors in [2]. ...
This paper proposes the installation of a new modular multilevel converter based highvoltage direct current (MMC-HVDC) system to connect between mainland and Jeju island power systems in Korea in 2020. The purpose is to combine with two old line-commutated converters (LCC)- based HVDC system to achieve a stability of the Jeju island power system. The operation of the overall system will be analyzed in three cases: (i) wind speed is variable, (ii) either one of the LCCHVDC systems is shutdown because of a fault or overhaul, (iii) a short circuit fault occurs at the mainland side. The effectiveness of the proposed control method is confirmed by the simulation results based on a PSCAD/EMTDC simulation program.
... With an ever-increasing wind power pentration into power system, the power system performance especially transient stability is influenced inevitablely [1][2][3][4][5]. The wind power system transient stability under severe grid fault is sundry, which is affected by diffierent types of wind turbines, various grid load models and unequal grid-connected capacity. ...
According to the characteristics like time-consuming and can not be quantitatively analyzed of time domain simulation in power system transient stability analysis, a direct method using information entropy combined with transient energy function method is proposed in this paper to analyze the transient stability of wind power system equiped with front-end speed controlled wind turbines (FSCWT) with synchronous generators. In which, the system kinetic energy and potential energy are used as information source to makeup information entropy function, then, a theoretical analysis of system transient stability is conducted. Based on this, simulations are carried out in IEEE 5-machine 14-bus system compared with the time domain’s, which verified the consistency of information entropy energy function (IEEF) method and time domain analysis. Results show that it is more intuitively and effectively to use IEEF method for wind power system transient analysis equiped with FSCWT.
... Large-scale wind power penetration impacts the electricity supply industry in many aspects and leads to fundamental changes in electric power systems. Integration of wind power into power systems presents challenges to power system planners and operators [2][3]. These challenges stem primarily from the stochastic nature of wind; power systems have to incorporate for first time a source of high uncertainty, high volatility, and low predictability. ...
Future high-voltage direct-current (HVDC) networks based on voltage source converters (VSCs) will have different structures (asymmetric monopolar, bipolar, or symmetric monopolar), voltage levels, control, and protection schemes. Therefore, dc–dc converters are needed to interconnect those VSC-HVDC grids and several technical issues on their control and operational systems must be adequately addressed. A dc–dc converter based on a modular-dual active bridge (M-DAB) converter is suggested to reach a desirable interconnection of the HVDC grids and regulate power flow (PF) between them. A dynamic averaged model is proposed for the M-DAB converter and its stability is analyzed using the Lyapunov function. Moreover, a new local controller based on nonlinear control theory is proposed for the M-DAB. The new M-DAB local controller is integrated with the energy management system (EMS), by updating the PF equations, to create a complete control structure. Considering the CIGRE DCS3 HVDC test system and the studied M-DAB, static, dynamic simulation, and experimental studies are conducted and the dc–dc converter and the performance of the designed controllers and the EMS are examined and validated.
The decarbonization plans are leading to the decommissioning of conventional power plants, resulting in a deep transformation of power systems. Balearic Islands are not an exception and, in order to compensate this generation reduction and increase the security of supply, a second HVDC link is planned to interconnect the Balearic power system to the Spanish mainland. In this application paper, Modular Multilevel Converters (MMCs) have been assumed as the preferred technology for this HVDC link. A transient analysis has been presented to evaluate the system performance after the introduction of this new HVDC link. Grid-following and grid-forming control strategies have been implemented, comparing their impact on the system performance and stability. The transient events considered are the disconnections of the main synchronous generators of the islands and AC faults in several locations of the Balearic power system. A final case based on a penetration of 100% of converter-based resources has been also simulated to study the islanded operation of the MMC-HVDC link.
Renewable and sustainable energy systems and policies have globally been promoted to transition from fossil fuel sources to environmentally friendly renewable energy sources such as wind power, photovoltaic energy, and fuel cells. Wind and solar energy sources are erratic and difficult to implement in renewable energy systems, therefore, circumspection is needed to implement such renewable energy systems and policies. Accordingly, this study develops an energy forecasting model with renewable energy technologies on which policy can be based, using the Korean energy policy as a case study. Deep learning-based models forecast fluctuating variation in electricity demand and generation, which are necessary in renewable energy system but not possible with conventional models. The gated recurrent unit shows the best prediction performance among the forecasting models evaluated, and is therefore selected as the base model to evaluate four different renewable energy scenarios. The scenarios are evaluated according to economic-environmental cost assessment. The optimal scenario uses an integrated gasification combined cycle, onshore and offshore wind farms, photovoltaic power stations, and fuel cell plants; in particular, this scenario shows the lowest economic-environmental costs, generates stable electricity for demand, and achieves a policy with 100% renewable energy. The optimal scenario is assessed by considering its strengths, weaknesses, opportunities, and threats analysis while also considering techno-economic-environmental domestic and global energy circumstances.
This paper proposes a new real-time load-support (RTLS) system with a coordinated control using electric boats (EBs), community generators and battery storage systems. It analyzes the management of the intermittent sources-dependent small-scale grid in real time, under various weather, and battery state-of-charge conditions. The RTLS system coordinates the customer's load demand with the available EBs, photovoltaics (PVs) and battery storage to provide load support and to regulate the bus voltage and frequency. The proposed system is validated both computationally in a real network and in a laboratory setup. It is found that this novel system can substantially reduce the grid load demand and maintain the power quality under various load/source uncertainties and fault conditions. The system robustness is also evaluated considering undesirable conditions, such as severe three-phase faults and sudden EB disconnections. The proposed method is compared with the day-ahead load-management approach to validate its effectiveness under various scenarios.
In this past few years, installation of distributed generator (DG) has become topic of interest in many countries due to rapid increase in energy and environmental issue. Generating power from renewable source has been proposed to compensate fossil fuel that is currently depleted. Wind power is one of the renewable energy sources that gains a huge attention, and many utilities are connecting wind power to distribution system. This number is going to get higher in the near future. Research on influence of wind power on system must be done in order to ensure the reliability of power system. This paper aims to study an impact of wind power-integrated distribution system when fault occurs in the system for various conditions. Many factors capable of changing system characteristics have been taken into account such as distribution system consisting of multi-wind power generation, size of wind power generation, fault type, and location of fault. Distribution system under this study is modeled based on 22 kv distribution network of Provincial Electricity Authority (PEA) in Thailand. Simulation will be done by using PSCAD/EMTP. Result obtained from case studies will be used to analyze and evaluate the effect of installation of wind power. The result indicates that the DG contributes significant fault current to the system when fault occurs.
The impact that renewable energy sources interfaced by power electronics have on power systems becomes more important as their share in the generation mix increases, thus requiring detailed analyses that take into account their dynamics and controllers. In this study, the impact of photovoltaic (PV) power plants on the power system of northern Chile is analysed. The studied plants employ a controller that allows power converters to interact with the grid like virtual synchronous generators, and their model includes the dynamics of the plant and converter controllers, as well as the dc and PV system. The presented analysis, which comprises modal analysis and time-domain simulations of large disturbances, evaluates the impact of these plants with respect to PV plants based on a conventional converter controller. Tests and validations of the proposed models and controllers are carried out for an actual PV plant connected to the power system of northern Chile, and for a higher PV penetration case. The results show the ability of PV plants formed by virtually synchronous power converters to limit frequency excursions induced by large power imbalances, and to mitigate power oscillations of the synchronous machines in the system.
With the rapid development of wind turbine, photovoltaicand battery technologies, renewable energy resources such as wind and solar become the most common distributedgenerations (DG) that are being integrated into microgrids. One key impediment is to determine the sizes and placements of DGs within which the microgrid can achieve its maximum potential benefits. The objective of the paper is to study and propose an approach to find the optimal sizes and placements of DGs in a microgrid. The authors propose a comprehensive objective function with practical constraints which take all the important factors that will impact the reliability of the power grid into account. To solve the optimization problem, genetic algorithm (GA) is used and compared with a mathematical optimization method nonlinear programming. The proposed model is tested on a real microgrid, i.e. Jeju Island, to evaluate and validate the performances of the approach. The simulation results present the optimal configuration of DGs for Jeju Island power grid. The analysis on results shows that GA maintains a delicate balance between performance and complexity. It is concluded that GA performs better not only in accuracy, stability, but also in computation time.
This paper presents fast screening techniques and process for grid interconnection of wind-storage systems. In a smart grid, the wind turbines are likely installed accompanying with battery energy storage systems, called “wind-storage system”, to largely increase the penetration of renewable energy. A fast screening approach based on a genetic algorithm with self-adaptive evolution provided from a commercial software, OPTIMUS, is applied to predetermine the maximum power output of a wind farm. The total power generation of a wind farm can be greatly increased without violating these limitations through the assistant of a battery energy storage system. Time-varying distribution system operating status make the operation problem of a wind-energy system further complicated. The results show that the maximum power output of a wind farm and the required capacity of the battery energy storage systems in a wind-storage system mainly depend on the system short-circuit capacity at the interconnection point of the wind-storage system. This paper confirms the effectiveness of the proposed algorithm using actual wind farm data and a physical distribution system of Taiwan. The outcomes of this paper are of value to fast screening the grid-interconnection applications of wind-storage systems.
The objective of this study is to determine the critical receiving power ratio (CRPR) of a receiving system fed only by high-voltage DC transmission lines. The approach is to check the voltage response when a severe fault occurs in a simplified asynchronously connected receiving system. The DC power limit is found by continuously increasing the DC power until the voltage cannot recover from the severe fault. The topic is expanded as follows. First, a simplified system model is established under a few reasonable assumptions. Then, the analytical voltage response expressions when a three-phase short-circuit fault occurs are developed, taking the effect of commutation failure, fast AC voltage control and load characteristics into consideration. The expressions of the DC power limits under different load characteristics are deduced from the analytical voltage response expressions. Besides, several crucial factors that limit the infeed power capacity of an asynchronously connected receiving system are discussed in this study based on the sensitivity analysis of the DC power limits. The CRPRs of a receiving system with different crucial characteristics are found through time-domain simulation with detailed models. The validity of the analytical voltage response expressions and the crucial factor analysis is well proved by the simulation results.
The variability and uncontrollability of wind power increases the difficulty for a power system operator to implement a wind power system with a high penetration rate. These are more serious factors to consider in small and isolated power systems since the system has small operating reserves and inertia to secure frequency and voltage. Typically, this difficulty can be reduced by interconnection with another robust power system using a controllable transmission system such as a high-voltage direct current (HVDC) system. However, the reliability and stability constraints of a power system has to be performed according to the HVDC system implementation. In this paper, the method for calculation of maximum wind power penetration in an island supplied by a HVDC power system is presented, and the operational strategy of a HVDC system is proposed to secure the power system reliability and stability. The case study is performed for the Jeju Island power system in the Korean smart grid demonstration area.
This paper presents the transient simulation results of an offshore wind farm connected to Taiwan Power System using a commercial power-system simulation software of PSS/E. A three-phase short-circuit fault is suddenly applied to one of the six feeders of the studied system. The simulated transient voltage variations, power fluctuations, and frequency deviations can be employed as an operation reference for a practical power system connected with different large-scale wind farms. The simulation transient results can also serve as a reference for the development of future offshore wind farms in Taiwan.
When a high-capacity offshore wind farm (OWF) is connected to a power system, the power quality of the power system can be significantly deteriorated under various wind speeds. This paper presents the analyzed voltage variations of Taiwan Power System connected with a 100-MW OWF using a commercial power system simulation software. The ultrahigh voltage bus of ten onshore substations that are close to the potential OWF is selected as the connection point. The voltage variation results at the connection points under different lengths of submarine cable are accomplished and analyzed when the 100-MW OWF is connected to the selected substations. The simulated results can offer a reference for the development of OWFs in Taiwan in the near future.
The increasing wind power penetration poses significant technical problems to the development of electric power systems. In this article, an integrated control strategy is proposed based on the characteristics of the directly driven permanent magnet synchronous generator wind turbine. The directly driven permanent magnet synchronous generator wind turbine is incorporated with superconducting magnetic energy storage, which can smooth the wind power fluctuations, enhance the low-voltage ride-through capability of the wind generation system, and achieve an uninterruptible power supply to local loads under isolated grid operation. According to the MATLAB/SIMULINK-based (The MathWorks, Natick, Massachusetts, USA) digital computer simulation model, the proposed control strategy is confirmed to be effective in power control of grid operation.
With wind power integrated into a grid, the impact of wind power on a power system becomes a major concern. This paper mainly investigates the impact of wind power integration considering three issues - wind speed, number of wind turbines or wind power penetration (WPP) level. The impact of wind power is analysed by the optimal power flow (OPF) tool. First, the OPF model with WPP is constructed. The Levenberg-Marquardt method was then employed to solve the OPF problem. Finally, numerical simulations for the modified IEEE-30 node system with WPP are carried out. According to the simulation results, the impacts of wind speed, wind turbine number and WPP level on the static performance of the power system are systematically analysed.
A five-year, NT$8.09 billion project to turn Penghu, Taiwan, into a world-class low-carbon island was formally launched in 2011. The project is a major milestone in Taiwan's development of renewable energy. The initiative, which will install large onshore wind power generators, is predicted to reduce carbon dioxide emissions by more than 50% in 2015 from 2005 levels. The study examines the plan for large onshore wind farms and the corresponding connected network, and performs simulation analysis for the integrated wind power system. Simulation results of the system impact analysis will be a valuable reference for the government and power utility. Additionally, this study examines several successful renewable development projects on other islands worldwide, the environmental conditions for the Penghu wind energy project, and the preplanning process for the Houliao Energy Park on Penghu.
This paper presents the transient simulated results of a three-phase short-circuit fault applied to one of the feeders of Jang-Bin wind farm connected to Taipower grid using a commercial power-system simulation software of PSS/E. The simulated transient voltage fluctuations, power variations, and frequency changes can serve as an operation reference for a power system connected with large-scale wind farms. It can also serve as a reference for the future development of Taiwan's offshore wind farms.
Heavy cooling load can lead to a load gap during the day and a peak-load regulation problem during the night in the area with onshore wind power installed. Fortunately, cold storage air conditioner (CSAC) can be used as a effective demand response resource to absorb onshore wind power. This paper establishes a mixed cold storage air conditioner demand response price incentive mechanism, in order to promote wind power storage by cold storage system at night, and a response evaluation model of CSAC, in order to effectively track the executive effect under different incentive mechanisms. The simulation of the coastal areas with prominent air-conditioning load in summer shows that when we implement price incentive mechanism on CSAC, system load and cost of peak load-regulation can effectively reduce, at the same time, wind power can obtain a good profit.
This paper mainly studies the main circuit topology, the working principle, modulation technique and control strategy of the STATCOM based on H-bridge. The STATCOM direct power control algorithm based on the virtual flux is used to control the AC side reactive power compensation, and in accordance with the principle of conservation of power, the DC side voltage imbalance factors are analyzed, and a distributed DC voltage control algorithm is also introduced. The DC side control algorithm is divided into upper and lower control parts, of which the upper control section is aimed at the average of DC side capacitor voltage of the sub-module unit for the STATCOM device, the lower control part is mainly for each sub-module DC side capacitor voltage. Finally, the control strategy is verified in a three level chain STATCOM system with VME control box as its core controller, and the experimental results show that the algorithm is feasible.
Renewable energy resource on islands is rich, which is of unique potential dominance in electricity development. In Taiwan, Green Island power system is a small, isolated system with a load level of 4.39 MW at peak and 0.81 MW at the minimum. It has been mainly fed from diesel generators. This paper is to study the effect of generator outage events on the system transient stability in the Green Island under a high penetration of renewable energy integration. Simulation results reveal that the system stability would not be affected and even improved as long as the renewable energy generators do not trip offline when system contingence occurs. Moreover, addition of one extra generator unit could significantly reduce the drop of the system's transient frequency. The work can provide several important operational experience to isolated micro grids with high penetration of renewable energy.
The modular multilevel converter (MMC) is a new type of
voltage source converter (VSC) for medium or high
voltage direct current (HVDC) power transmission. This
paper proposes the installation of a new HVDC system,
HVDC#3, by using MMC systems to transfer power
between mainland and Jeju island power systems in Korea
in 2020 beside the operation of two old line-commutated
converter (LCC)-based HVDC systems. The control
strategies of MMC-HVDC will be first analyzed. The
operation of MMC-HVDC system for stabilizing Jeju
power system will be then tested in two cases. First case
is the operation of MMC for stabilizing power when wind
power is variable. Other case is the control of MMC since
a fault occurs in one of two old LCC-HVDC systems. The
simulation results using PSCAD simulation program will
confirm the effectiveness of the proposed method.
When a large-scale offshore wind farm (OWF) is connected to a power system, the power quality of the connected power system can be significantly deteriorated under various operating conditions and employed parameters. This paper presents the analyzed results of voltage variations and short-circuit ratio (SCR) of Taiwan Power System connected with a large-scale OWF of 100 MW using a commercial power-system simulation software. Ten ultra-high-voltage bus of onshore substations that are close to the potential OWF are properly selected as the connection points. The voltage variations and SCR results at the connection points under different lengths of submarine cable are accomplished and analyzed when the OWF is connected to the selected buses. The simulated results can offer a reference for the development of OWFs in Taiwan in the near future.
This paper presents the simulation results of a large-scale offshore wind farm (OWF) connected to the point of common coupling (PCC) of Taiwan Power System using a commercial power-system simulation software. The ultra-high-voltage buses of an onshore substation in Changhua near the potential OWF are properly selected as the connection points. The voltage variations and power factors at the PCC under different lengths of submarine cable and various OWF capacities are simulated and analyzed when the studied OWF is connected to the selected buses. The simulated results can offer a reference for the development of large-scale OWFs in Taiwan in the near future.
When a large-scale offshore wind farm (OWF) is connected to a power system, the quality of the connected power system can be significantly deteriorated under different operating conditions. This paper presents the analyzed voltage-variation results when Taiwan Power System is connected with a large-scale OWF with different OWF capacities and various lengths of submarine cable. A commercial power-system simulation software is employed to simulate the results. The ultra-high-voltage buses of onshore substations that are close to the potential OWF are properly selected as the connection points. The voltage-variation results at the connection points under different lengths of submarine cable and OWF capacities are accomplished and analyzed when the OWF is connected to the selected buses. The simulated results can offer a reference for the development of OWFs in Taiwan in the near future.
The optimal control of state-of-charge (SOC) for superconducting magnetic energy storage (SMES), which is used to smooth power fluctuations from wind turbine, is essential to improve its technical and economical performance. Without an efficient control strategy, the SMES may go to the state of over-charge or deep-discharge, which will pose a significant effect on its service life and its technical performance. In this study, combined with wind forecasting technology and real-time monitoring of SOC for the SMES, a double fuzzy logic control strategy is proposed that is applied to regulate SOC of SMES with the purpose of not only effectively smoothing the power fluctuations of wind turbine, but also preventing the SMES from occurring of the state of over-charge/deep-discharge and adjusting it to the appropriate SOC. The effectiveness of the proposed control strategy is verified by the simulation results.
Integrating a battery energy storage system (BESS) with a wind farm can smooth power fluctuations from the wind farm. Battery storage capacity (C), maximum charge/discharge power of battery (P) and smoothing time constant (T) for the control system are three most important parameters that influence the level of smoothing (LOS) of output power transmitted to the grid. The economic cost (EC) of a BESS should also be taken into consideration when determining the characteristic parameters of BESS (C, P). In this study, an artificial neural network-based long-term model of evaluated BESS technical performance and EC is established to reflect the relationship between the three parameters (C, P, T) and LOS of output power transmitted to the grid, the EC of BESS. After that, genetic algorithm is used to find optimal parameter combination of C, P and T by optimising the objective function derived from the mathematical model constructed. The simulation results of the example indicate that the parameter combination of C, P and T obtained by the proposed method can better not only meet the technical demand but also achieve maximum economic profit.
The stability problem of power networks becomes increasingly important since the rapid development and broad application of wind energy technology. We continue to lack a well-established mathematical model to describe and characterize power systems associated with wind power in essence of random properties. Here, we present a novel model to solve this significant problem by incorporating the nonlinear dynamical theory and the fluctuation nature of wind energy. The model produces some interesting dynamical phenomena, e.g., routes to chaos. To eliminate the chaotic behavior which is disadvantageous to the stability and normal functioning of the whole system, we offer a fuzzy control approach to drive the system with uncertain parameters from chaotic states to steady states. The control method is validated by both numerical simulations and theoretical analysis. Our theory and control scheme can be expected to be potentially applicable in a variety of power systems with wind sources.
New perspectives on using induction generators in alternative energy technologies Durable and cost-effective, induction power generators have undergone numerous improvements that make them an increasingly attractive option for renewable energy applications, particularly for wind and hydropower generation systems. From fundamental concepts to the latest technologies, Alternative Energy Systems: Design and Analysis with Induction Generators, Second Edition provides detailed and accurate coverage of all aspects related to the design, operation, and overall analysis of such systems. Placing a greater emphasis on providing clear, precise, and succinct explanations, this second edition features new, revised, and updated content as well as figures, tables, equations, and examples. Each chapter introduces a multi-step, chapter-length problem relating the material to a real application. The solution appears at the end of the chapter, along with additional practice problems and references. New Material in This Edition: • Updated definitions for generated power and efficiency • Technological advances, such as new applications using doubly-fed induction generators • New methodologies, such as the magnetization curve representation for induction generators • Additional focus on renewable energy applications such as sea, wind, and hydropower systems • Totally re-written and updated chapter covering doubly-fed induction generators Alternative Energy Systems provides the tools and expertise for advanced students and professionals in electrical, mechanical, civil, and environmental engineering involved in the development of power plants.
This paper presents a study on reliability evaluation of a power system considering wind turbine generators (WTG) with multi-state. Renewable energy resources such as wind, wave, solar, micro hydro, tidal and biomass etc. are becoming importance stage by stage because of considering effect of the environment. Wind energy is one of the most successful sources of renewable energy for the production of electrical energy. But, reliability evaluation of generating system with wind energy resources is a complex process. While the wind turbine generators can not modelled as two-state model as like as conventional generators, they should be modelled as multi-state model due to wind speed random variation. The methodology for obtaining reliability evaluation index of wind turbine generators is different from it of the conventional generators. A method for making outage capacity probability table of WTG for reliability is proposed in this paper. The detail process is presented using case study of simple system.
The interaction between bulk windfarm generation and conventional generation and its influence on network dynamic characteristics are investigated. A simple three-generator system having characteristics that may be considered representative of the major areas of the UK network is used for the dynamic studies. Time response simulation and eigenvalue analysis are used to establish basic transient and dynamic stability characteristics. The wind generation is provided either by windfarms based on Fixed Speed Induction Generators (FSIGs) or Doubly Fed Induction Generators (DFIGs). In addition, in order to provide a base-line, against which windfarm influence on network dynamics can be judged, the case where the power is provided only by conventional synchronous generation is also considered.
This paper describes a method of initialising dynamic wind turbine models in power-system simulations. The method uses grid-status information to initialise the grid-connected wind turbine model. The goal is to start a power-system simulation in a stationary state, without unnecessary transient behaviour at the beginning of the simulation. Correct initialisation is necessary to reach quickly the steady state of the grid-connected wind turbine, before a real transient on the grid occurs. Consequently, the dynamic performance of the system can be independently and accurately evaluated. The method presented considers wind turbines with directly grid-connected induction generators, with constant or variable blade angle (passive stall control, blade angle control or active stall control). These aspects apply to both constant and variable speed wind turbines. The investigation is performed in the commercial dedicated power-system simulation-tool DIgSILENT. Attention is especially drawn to the initialisation of the non-electrical parts of the wind turbine. The suitability of this initialisation strategy is illustrated by an example.
This paper presents the progress in distributed generation in Korea. The government policy has emphasized mainly on three different renewable energy sources, namely, hydrogen and fuel cell, photovoltaic, and wind power. Concerning renewable energy, the government plans to replace 5% of the primary energy source by the year 2011. The road map for the three major renewable energy sources is presented.
The importance of renewable energy sources has been growing at a high rate as a result of being environment friendly. In particular, wind power is one of the most successfully utilized of such sources to produce electrical energy. The available wind energy depends on the wind speed, which is a random variable. For the wind-farm operator, this poses difficulty in the system scheduling and energy dispatching, as the schedule of the wind-power availability is not known in advance. This paper proposes to use the two-layered artificial neural networks for predicting the actual wind speed from the previous values of the same variable.
Generation of electricity using wind power has received considerable attention worldwide in recent years. In order to investigate the impacts of the integration of wind farm into utilities' network various windmill models have been developed. One such impact is related to the critical clearing time (CCT) of the wind power based embedded generators (WPBEG). The work in this paper has shown that oversimplification of the modeling of windmill mechanical drive train could introduce significant error in the value of the CCT that defines the stability limit of an integrated wind farm. This paper also reports investigation into the factors that influence the dynamic behavior of the WPBEGs following network fault conditions. It is shown that wind farm CCT can be affected by various factors contributed by the host network. Results obtained from several case studies are presented and discussed. This investigation is conducted on a simulated grid-connected wind farm using EMTP.
Fuel cell as an alternative distributed generation source under deregulated power system
- K Y Lee
- S.-H Kim
- E.-H Kim
- H.-C Kim
Farret Renewable Energy Systems: Design and Analysis with Induction Generator
- M G Simoes
A study on wind speed prediction using artificial neural network at Jeju island in Korea
- L Wu
- J G Park
- J S Choi
- K Y Lee
- A A El-Keib
- J Watada
Effect of correlation coefficient of wind speed on the probabilistic reliability evaluation of power system considering wind turbine-generator
- L Wu
- J G Park
- J S Choi
- K Y Lee