With the increase of wind power capacity in China, the situation of curtailment of wind power is getting worse. An annual sequence production simulation model is established with maximum wind power consumption as the ...With the increase of wind power capacity in China, the situation of curtailment of wind power is getting worse. An annual sequence production simulation model is established with maximum wind power consumption as the objective function. The calculation of specific power grid operation in 2013 verifies the precision of this model. The impact of different factors on wind power accommodation as well as the impact of power grid reserve, wind resources and load on wind power curtailment is analyzed. The calculation results quantify the impact of different factors from power system to the accommodation of wind power and provide reference to solving the problem of wind power curtailment.展开更多
In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multipl...In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multiplexing systems. During the SCR procedure, only the element with the maximal amplitude is picked for processing, which not only decreases the algorithm complexity, but also helps to overcome the BER deterioration. With the LSA method, the amplitude of the peak-cancelling signals can approximate to that of the original clipping noise as much as possible. Through the combination of the optimization factor in the LSA method, the classic SCR method can achieve better PAPR reduction with faster convergence. Simulation results show that the proposed SCR-LSA TR scheme has less in-band distortion and smaller out-of-band spectral radiation. The BER of the proposed scheme shows a better performance especially under the 16-QAM over the additive white Gaussian noise channel.展开更多
There is a false notion of existing available, abundant, and long lasting fuel energy in the Gulf Cooperation Council (GCC) Countries;with continual income return from its exports. This is not true as the sustainabili...There is a false notion of existing available, abundant, and long lasting fuel energy in the Gulf Cooperation Council (GCC) Countries;with continual income return from its exports. This is not true as the sustainability of this income is questionable. Energy problems started to appear, and can be intensified in coming years due to continuous growth of energy demands and consumptions. The demands already consume all produced Natural Gas (NG) in all GCC, except Qatar;and the NG is the needed fuel for Electric Power (EP) production. These countries have to import NG to run their EP plants. Fuel oil production can be locally consumed within two to three decades if the current rate of consumed energy prevails. The returns from selling the oil and natural gas are the main income to most of the GCC. While NG and oil can be used in EP plants, NG is cheaper, cleaner, and has less negative effects on the environment than fuel oil. Moreover, oil has much better usage than being burned in steam generators of steam power plants or combustion chambers of gas turbines. Introducing renewable energy or nuclear energy may be a necessity for the GCC to keep the flow of their main income from exporting oil. This paper reviews the GCC productions and consumptions of the prime energy (fuel oil and NG) and their role in electric power production. The paper shows that, NG should be the only fossil fuel used to run the power plants in the GCC. It also shows that the all GCC except Qatar, have to import NG. They should diversify the prime energy used in power plants;and consider alternative energy such as nuclear and renewable energy, (solar and wind) energy.展开更多
This paper presents a practical pricing model for backup reserve and wheeling, which attains a balanced strategy that ensures perceived benefits to both the buyer and the seller. The model and the associated computeri...This paper presents a practical pricing model for backup reserve and wheeling, which attains a balanced strategy that ensures perceived benefits to both the buyer and the seller. The model and the associated computerized algorithm deal collectively with diverse issues, including： （1） fulfilling local firm real （and reactive） power demand requirements, （2） fulfilling local power reserve requirements, （3） buying firm real （and reactive） power from the grid, （4） buying reserve power from the grid, （5） exporting firm real （and reactive） power demand to remote load centers via the grid, （6） exporting reserve power via the grid, （7） wheeling of firm power demand to remote owned sites using the grid, and （8） wheeling reserve power to remote owned sites using grid. Practical implementation features of the computerized algorithms are also discussed with an illustrative case example.展开更多
To maximize conversion efficiency,photovoltaic(PV)systems generally operate in the maximum power point tracking(MPPT)mode.However,due to the increasing penetra tion level of PV systems,there is a need for more develop...To maximize conversion efficiency,photovoltaic(PV)systems generally operate in the maximum power point tracking(MPPT)mode.However,due to the increasing penetra tion level of PV systems,there is a need for more developed control functions in terms of frequency support services and voltage control to maintain the reliability and stability of the power grid.Therefore,flexible active power control is a manda tory task for grid-connected PV systems to meet part of the grid requirements.Hence,a significant number of flexible pow er point tracking(FPPT)algorithms have been introduced in the existing literature.The purpose of such algorithms is to real ize a cost-effective method to provide grid support functional ities while minimizing the reliance on energy storage systems.This paper provides a comprehensive overview of grid support functionalities that can be obtained with the FPPT control of PV systems such as frequency support and volt-var control.Each of these grid support functionalities necessitates PV sys tems to operate under one of the three control strategies,which can be provided with FPPT algorithms.The three control strate gies are classified as:①constant power generation control(CP GC),②power reserve control(PRC),and③power ramp rate control(PRRC).A detailed discussion on available FPPT algo rithms for each control strategy is also provided.This paper can serve as a comprehensive review of the state-of-the-art FPPT algorithms that can equip PV systems with various grid support functionalities.展开更多
提出一种部分传输序列(partial transm it sequence,PTS)算法与载波预留法(tone reservation)相结合的算法来降低OFDM系统峰均功率比(peak-to-average power ratio,PAPR).传统的PTS算法可以在不使信号失真的情况下很好地降低高PAPR出现...提出一种部分传输序列(partial transm it sequence,PTS)算法与载波预留法(tone reservation)相结合的算法来降低OFDM系统峰均功率比(peak-to-average power ratio,PAPR).传统的PTS算法可以在不使信号失真的情况下很好地降低高PAPR出现的概率,但是这种算法的缺点是计算量过大.而TR法虽有不用传递边带信息的优点,但当预留子载波取值小时会得不到理想的性能,取值过大又会浪费系统功率.联合算法在大大地降低了PTS计算量、TR预留载波取值小的同时,还保持了良好的PAPR性能,仿真结果验证了其有效性.展开更多
采用正交频分复用(orthogonal frequency division multiplexing,OFDM)信号作为雷达通信一体化发射信号时,由于OFDM信号具有比较高的峰值平均功率比(peak-toaverage power ratio,PAPR),不利于一体化信号的线性传输。为解决上述问题,首...采用正交频分复用(orthogonal frequency division multiplexing,OFDM)信号作为雷达通信一体化发射信号时,由于OFDM信号具有比较高的峰值平均功率比(peak-toaverage power ratio,PAPR),不利于一体化信号的线性传输。为解决上述问题,首先提出了一种基于子载波复用的OFDM雷达通信一体化波形,然后提出削峰算法来抑制PAPR。在发挥子载波灵活调制与分配优势的基础上,利用空白子载波调制削峰信号,以较低的复杂度和迭代次数,在对雷达和通信子载波不产生任何影响的前提下,抑制一体化信号的PAPR。仿真结果表明,所提出的抑制方法能够产生一定幅度的削峰信号来较好地抑制一体化信号的PAPR。展开更多
综合研究正交频分多址(Orthogonal Frequency Division Multiple Access,OFDMA)系统中资源分配和峰值平均功率比(Peak to Average Power Ratio,PAPR)抑制问题,提出一种OFDMA子载波分配与子载波预留(Tone Reservation,TR)技术联合优化方...综合研究正交频分多址(Orthogonal Frequency Division Multiple Access,OFDMA)系统中资源分配和峰值平均功率比(Peak to Average Power Ratio,PAPR)抑制问题,提出一种OFDMA子载波分配与子载波预留(Tone Reservation,TR)技术联合优化方法。该方法利用部分子载波降低系统PAPR,同时对系统进行自适应子载波分配达到联合优化。仿真结果表明,该方法中系统的PAPR抑制效果和吞吐量参数能够同时得到优化。展开更多
In a deregulated Var market, market power issue is more serious than in an energy market since reactive power cannot be transmitted over long distances. This letter designs a multi-timescale Var market framework, wher...In a deregulated Var market, market power issue is more serious than in an energy market since reactive power cannot be transmitted over long distances. This letter designs a multi-timescale Var market framework, where market power that may arise in the hourly-ahead Var support service market due to system configuration deficiency and market structure flaws can be eliminated by day-ahead contract-based Var reserve service market. Settlement of day-ahead Var reserve contract is formulated as a two-stage robust optimization (TSRO) model considering worst case of uncertainty realization and potential market power that may arise in hourly-ahead market. TSRO with integer recourses is then solved by a new column and constraint generation algorithm. Results show a robust Var reserve contract can fully eliminate market power, and prevent suppliers from manipulating market prices.展开更多
With the increasing proportion of renewable energy sources(RESs)in power grid,the reserve resource(RR)scarcity for correcting power deviation of RESs has become a potential issue.Consequently,the power curve of RES ne...With the increasing proportion of renewable energy sources(RESs)in power grid,the reserve resource(RR)scarcity for correcting power deviation of RESs has become a potential issue.Consequently,the power curve of RES needs to be more rigorously assessed.The RR scarcity varies during different time periods,so the values of assessment indicators should be dynamically adjusted.The assessment indicators in this paper include two aspects,i.e.,deviation exemption ratio and penalty price.Firstly,this paper proposes a method for dynamically calculating the supply capacity and RR cost,primarily taking into account the operating status of thermal units,forecast information of RES,and load curve.Secondly,after clarifying the logical relationship between the degree of RR scarcity and the values of assessment indicators,this paper establishes a mapping function between them.Based on this mapping function,a dynamic setting method for assessment indicators is proposed.In the future,RES will generally be equipped with battery energy storage systems(BESSs).Reasonably utilizing BESSs to reduce the power deviation of RESs can increase the expected income of RESs.Therefore,this paper proposes a power curve optimization strategy for RESs considering self-owned BESSs.The case study demonstrates that the dynamic setting method of assessment indicators can increase the revenue of RESs while ensuring that the penalty fees paid by RESs to the grid are sufficient to cover the RR costs.Additionally,the power curve optimization strategy can help RESs further increase income and fully utilize BESSs to reduce power deviation.展开更多
文摘With the increase of wind power capacity in China, the situation of curtailment of wind power is getting worse. An annual sequence production simulation model is established with maximum wind power consumption as the objective function. The calculation of specific power grid operation in 2013 verifies the precision of this model. The impact of different factors on wind power accommodation as well as the impact of power grid reserve, wind resources and load on wind power curtailment is analyzed. The calculation results quantify the impact of different factors from power system to the accommodation of wind power and provide reference to solving the problem of wind power curtailment.
基金support by the National Natural Science Foundation of China (61401360)the Fundamental Research Funds for the Central Universities (3102017zy026)+1 种基金the Natural Science Basic Research Plan in Shaanxi Province of China (2016JM6017)the Scientific Research Program Funded by Shaanxi Provincial Education Department (16JK1702)
文摘In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multiplexing systems. During the SCR procedure, only the element with the maximal amplitude is picked for processing, which not only decreases the algorithm complexity, but also helps to overcome the BER deterioration. With the LSA method, the amplitude of the peak-cancelling signals can approximate to that of the original clipping noise as much as possible. Through the combination of the optimization factor in the LSA method, the classic SCR method can achieve better PAPR reduction with faster convergence. Simulation results show that the proposed SCR-LSA TR scheme has less in-band distortion and smaller out-of-band spectral radiation. The BER of the proposed scheme shows a better performance especially under the 16-QAM over the additive white Gaussian noise channel.
文摘There is a false notion of existing available, abundant, and long lasting fuel energy in the Gulf Cooperation Council (GCC) Countries;with continual income return from its exports. This is not true as the sustainability of this income is questionable. Energy problems started to appear, and can be intensified in coming years due to continuous growth of energy demands and consumptions. The demands already consume all produced Natural Gas (NG) in all GCC, except Qatar;and the NG is the needed fuel for Electric Power (EP) production. These countries have to import NG to run their EP plants. Fuel oil production can be locally consumed within two to three decades if the current rate of consumed energy prevails. The returns from selling the oil and natural gas are the main income to most of the GCC. While NG and oil can be used in EP plants, NG is cheaper, cleaner, and has less negative effects on the environment than fuel oil. Moreover, oil has much better usage than being burned in steam generators of steam power plants or combustion chambers of gas turbines. Introducing renewable energy or nuclear energy may be a necessity for the GCC to keep the flow of their main income from exporting oil. This paper reviews the GCC productions and consumptions of the prime energy (fuel oil and NG) and their role in electric power production. The paper shows that, NG should be the only fossil fuel used to run the power plants in the GCC. It also shows that the all GCC except Qatar, have to import NG. They should diversify the prime energy used in power plants;and consider alternative energy such as nuclear and renewable energy, (solar and wind) energy.
文摘This paper presents a practical pricing model for backup reserve and wheeling, which attains a balanced strategy that ensures perceived benefits to both the buyer and the seller. The model and the associated computerized algorithm deal collectively with diverse issues, including： （1） fulfilling local firm real （and reactive） power demand requirements, （2） fulfilling local power reserve requirements, （3） buying firm real （and reactive） power from the grid, （4） buying reserve power from the grid, （5） exporting firm real （and reactive） power demand to remote load centers via the grid, （6） exporting reserve power via the grid, （7） wheeling of firm power demand to remote owned sites using the grid, and （8） wheeling reserve power to remote owned sites using grid. Practical implementation features of the computerized algorithms are also discussed with an illustrative case example.
基金supported in part by the Future Battery Industries Cooperative Research Center(www.fbicrc.com.au)as part of the Australian Government’s CRC Program(www.business.gov.au),which supports industry-led collaborations between industry,researchers and the community.
文摘To maximize conversion efficiency,photovoltaic(PV)systems generally operate in the maximum power point tracking(MPPT)mode.However,due to the increasing penetra tion level of PV systems,there is a need for more developed control functions in terms of frequency support services and voltage control to maintain the reliability and stability of the power grid.Therefore,flexible active power control is a manda tory task for grid-connected PV systems to meet part of the grid requirements.Hence,a significant number of flexible pow er point tracking(FPPT)algorithms have been introduced in the existing literature.The purpose of such algorithms is to real ize a cost-effective method to provide grid support functional ities while minimizing the reliance on energy storage systems.This paper provides a comprehensive overview of grid support functionalities that can be obtained with the FPPT control of PV systems such as frequency support and volt-var control.Each of these grid support functionalities necessitates PV sys tems to operate under one of the three control strategies,which can be provided with FPPT algorithms.The three control strate gies are classified as:①constant power generation control(CP GC),②power reserve control(PRC),and③power ramp rate control(PRRC).A detailed discussion on available FPPT algo rithms for each control strategy is also provided.This paper can serve as a comprehensive review of the state-of-the-art FPPT algorithms that can equip PV systems with various grid support functionalities.
文摘提出一种部分传输序列(partial transm it sequence,PTS)算法与载波预留法(tone reservation)相结合的算法来降低OFDM系统峰均功率比(peak-to-average power ratio,PAPR).传统的PTS算法可以在不使信号失真的情况下很好地降低高PAPR出现的概率,但是这种算法的缺点是计算量过大.而TR法虽有不用传递边带信息的优点,但当预留子载波取值小时会得不到理想的性能,取值过大又会浪费系统功率.联合算法在大大地降低了PTS计算量、TR预留载波取值小的同时,还保持了良好的PAPR性能,仿真结果验证了其有效性.
文摘采用正交频分复用(orthogonal frequency division multiplexing,OFDM)信号作为雷达通信一体化发射信号时,由于OFDM信号具有比较高的峰值平均功率比(peak-toaverage power ratio,PAPR),不利于一体化信号的线性传输。为解决上述问题,首先提出了一种基于子载波复用的OFDM雷达通信一体化波形,然后提出削峰算法来抑制PAPR。在发挥子载波灵活调制与分配优势的基础上,利用空白子载波调制削峰信号,以较低的复杂度和迭代次数,在对雷达和通信子载波不产生任何影响的前提下,抑制一体化信号的PAPR。仿真结果表明,所提出的抑制方法能够产生一定幅度的削峰信号来较好地抑制一体化信号的PAPR。
文摘综合研究正交频分多址(Orthogonal Frequency Division Multiple Access,OFDMA)系统中资源分配和峰值平均功率比(Peak to Average Power Ratio,PAPR)抑制问题,提出一种OFDMA子载波分配与子载波预留(Tone Reservation,TR)技术联合优化方法。该方法利用部分子载波降低系统PAPR,同时对系统进行自适应子载波分配达到联合优化。仿真结果表明,该方法中系统的PAPR抑制效果和吞吐量参数能够同时得到优化。
文摘In a deregulated Var market, market power issue is more serious than in an energy market since reactive power cannot be transmitted over long distances. This letter designs a multi-timescale Var market framework, where market power that may arise in the hourly-ahead Var support service market due to system configuration deficiency and market structure flaws can be eliminated by day-ahead contract-based Var reserve service market. Settlement of day-ahead Var reserve contract is formulated as a two-stage robust optimization (TSRO) model considering worst case of uncertainty realization and potential market power that may arise in hourly-ahead market. TSRO with integer recourses is then solved by a new column and constraint generation algorithm. Results show a robust Var reserve contract can fully eliminate market power, and prevent suppliers from manipulating market prices.
基金supported in part by the National Natural Science Foundation of China(No.51877049).
文摘With the increasing proportion of renewable energy sources(RESs)in power grid,the reserve resource(RR)scarcity for correcting power deviation of RESs has become a potential issue.Consequently,the power curve of RES needs to be more rigorously assessed.The RR scarcity varies during different time periods,so the values of assessment indicators should be dynamically adjusted.The assessment indicators in this paper include two aspects,i.e.,deviation exemption ratio and penalty price.Firstly,this paper proposes a method for dynamically calculating the supply capacity and RR cost,primarily taking into account the operating status of thermal units,forecast information of RES,and load curve.Secondly,after clarifying the logical relationship between the degree of RR scarcity and the values of assessment indicators,this paper establishes a mapping function between them.Based on this mapping function,a dynamic setting method for assessment indicators is proposed.In the future,RES will generally be equipped with battery energy storage systems(BESSs).Reasonably utilizing BESSs to reduce the power deviation of RESs can increase the expected income of RESs.Therefore,this paper proposes a power curve optimization strategy for RESs considering self-owned BESSs.The case study demonstrates that the dynamic setting method of assessment indicators can increase the revenue of RESs while ensuring that the penalty fees paid by RESs to the grid are sufficient to cover the RR costs.Additionally,the power curve optimization strategy can help RESs further increase income and fully utilize BESSs to reduce power deviation.
