To facilitate the achieving of the goal of“eliminating viral hepatitis as a major public health threat by 2030”set by the World Health Organization,the Chinese Society of Hepatology together with the Chinese Society...To facilitate the achieving of the goal of“eliminating viral hepatitis as a major public health threat by 2030”set by the World Health Organization,the Chinese Society of Hepatology together with the Chinese Society of Infectious Diseases(both are branches of the Chinese Medical Association)organized a panel of experts and updated the guidelines for prevention and treatment of chronic hepatitis B in China(version 2022).With the support of available evidence,this revision of the guidelines focuses on active prevention,large scale testing,and expansion of therapeutic indication of chronic hepatitis B with the aim of reducing the hepatitis B related disease burden.展开更多
In 2015, the Chinese Society of Hepatology and the Chinese Society of Gastroenterology published a consensus on pri-mary biliary cholangitis (PBC). In the past years, numerous clinical studies have been published in t...In 2015, the Chinese Society of Hepatology and the Chinese Society of Gastroenterology published a consensus on pri-mary biliary cholangitis (PBC). In the past years, numerous clinical studies have been published in the field of PBC. To guide the clinical diagnosis and management of PBC patients, the Chinese Society of Hepatology invited a panel of experts to assess the new clinical evidence and formulate the current guidelines.展开更多
The National Electricity Market(NEM)in Australia was suspended during June 15-23,2022,with a primary attribution to the lack of available generation capacity.This incident is noteworthy because it was the first market...The National Electricity Market(NEM)in Australia was suspended during June 15-23,2022,with a primary attribution to the lack of available generation capacity.This incident is noteworthy because it was the first market suspension in NEM’s history and took place in a major energy exporting country.In this letter,we review the outline and impacts of the incident.From the perspectives of market regulation,electricity supply,and electricity demand,we identify three underlying causes of the market suspension and offer four recommendations for the market mechanism evolution to ensure power supply security.展开更多
Increasing penetration of renewable energy generation poses a challenge to power system inertia adequacy.It is vital to provide long-term incentive signals to induce a generation mix with adequate inertia supply.Howev...Increasing penetration of renewable energy generation poses a challenge to power system inertia adequacy.It is vital to provide long-term incentive signals to induce a generation mix with adequate inertia supply.However,existing literature rarely studies inertia incentive mechanisms or considers inertia constraints when making generation investment decisions.Thus,we propose an inertia market to quantify the value of inertia and to remunerate inertia provision.To examine the impacts of the inertia market on generation mix,we then propose a stochastic bilevel generation investment equilibrium model that depicts a multi-leader and multi-follower Stackelberg game.The lower level of the model considers the proposed inertia market,along with the energy,reserve,and capacity markets.The upper level considers multiple profit-maximizing strategic producers,and each producer is able to build gas-fired generators,wind generators,and energy storages.Numerical experiments demonstrate that a generation mix with adequate inertia supply can be induced with the proposed inertia market whereas there can be inertia shortage without the inertia market.Interestingly,considering carbon taxes,it is more cost-competitive to invest in wind resources with virtual inertia facilities than to substitute wind resources by thermal generators.Correspondingly,the introduction of an inertia market does not significantly reduce wind generation shares but boosts virtual inertia facility penetration.Our findings imply a future power system powered by fully decarbonized power resources with adequate inertia.展开更多
To facilitate the achieving of the goal of“eliminating viral hepatitis as a major public health threat by 2030”set by theWorld Health Organization,the Chinese Society of Hepatology together with the Chinese Society ...To facilitate the achieving of the goal of“eliminating viral hepatitis as a major public health threat by 2030”set by theWorld Health Organization,the Chinese Society of Hepatology together with the Chinese Society of Infectious Diseases(both are branches of the ChineseMedical Association)organized a panel of experts and updated the guidelines for prevention and treatment of chronic hepatitis B in China(version 2022).With the support of available evidence,this revision of the guidelines focuses on active prevention,large-scale testing,and expansion of therapeutic indication of chronic hepatitis B with the aim of reducing the hepatitis B–related disease burden.展开更多
Background and Aims:Ravidasvir(RDV)is a new generation pangenotypic hepatitis C virus(HCV)NS5A inhibitor,with high barrier to baseline resistance-associated species.This is the first phase 2/3 study conducted in China...Background and Aims:Ravidasvir(RDV)is a new generation pangenotypic hepatitis C virus(HCV)NS5A inhibitor,with high barrier to baseline resistance-associated species.This is the first phase 2/3 study conducted in China's Mainland confirming the efficacy and safety of RDV+ritonavir-boosted danoprevir+ribavirin for 12 weeks in treatment-naive noncirrhotic patients with genotype 1 infection in a large population.Methods:In this multicenter,randomized,doubleblinded,placebo-controlled phase 2/3 trial(NCT03362814),we enrolled 424 treatment-nafve,noncirrhotic adult HCV genotype 1 patients.All patients were randomized at 3∶1 ratio to receive a combination of RDV 200mg once daily plus ritonavir-boosted danoprevir 100mg/100mg twice daily and oral ribavirin 1000/1200mg/day(body weight<75/≥75 kg)(n=318)or placebo(n=106)for 12 weeks.The primary end-point was the rate of sustained virologic response 12 weeks after the end of treatment,and the safety was evaluated and compared between treatment and placebo groups.Results:The overall rate of sustained virological response at 12 weeks after treatment is 99%(306/309,95%,CI:97%-100%)under per protocol set analysis.All patients harboring baseline NS5A resistance-associated species in the treatment group(76/76,per protocol set)achieved sustained virological response at 12 weeks after treatment.No treatment-related serious adverse events were reported.Laboratory abnormalities showed mild or moderate severity(grade 1 and grade 2)in liver function tests.Conclusions:In treatment-na(i)ve,noncirrhotic HCV Chinese patients infected with HCV genotype 1,all-oral regimen of RDV+ritonavir-boosted danoprevir+ribavirin for 12 weeks was highly efficacious,safe,and well tolerated.展开更多
Background and Aims:Genotype(GT)1 remains the predominant hepatitis c virus(HCV)GT in Chinese patients.Over 80%of those Chinese patients harbor the interferon-sensitive CC allele of IFNL4rs12979860,which is favorable ...Background and Aims:Genotype(GT)1 remains the predominant hepatitis c virus(HCV)GT in Chinese patients.Over 80%of those Chinese patients harbor the interferon-sensitive CC allele of IFNL4rs12979860,which is favorable for interferon-based treatment regimens.This phaseⅢclinical trial aimed to evaluate the efficacy and safety of the ritonavirboosted danoprevir plus pegylated-interferonα-2a and ribavirin regimen for 12 weeks in treatment-na(i)ve mainland Chinese patients infected with HCV GT1 without cirrhosis.Methods:One hundred and forty-one treatment-na(i)ve,non-cirrhotic HCV GT1 Chinese patients(age≥18 years)were enrolled for this single-arm,multicenter,phaseⅢMANASA study(NCT03020082).Patients received a combination of ritonavir-boosted danoprevir(100 mg/100 mg)twice a day plus subcutaneous injection of weekly pegylated-interferonα-2a(180μg)and oral ribavirin(1000/1200 mg/day body weight<75/≥75 kg)for 12 weeks.The primary end-point was sustained virologic response rate at 12 weeks after the end of treatment.The secondary end-points were safety outcomes,tolerability,virologic response over time and relapse rate.Results:All enrolled patients were HCV GT1-infected,and most among them(97.9%,123/141)had the HCV GT1b subtype.Single-nucleotide polymorphism test showed that the majority of patients were of the IFNL4 rs12979860 CC genotype(87.2%,123/141).Overall,140 patients completed the 12-week treatment,and 97.1%(136/140)patients achieved sustained virologic response at 12 weeks(per protocol population group,95%confidence interval:92.9-99.2%).Only drug-related serious adverse event occurred.Most of the adverse events were grade 1 and grade 2 alanine aminotransferase elevation or liver dysfunction.One patient discontinued treatment because of severe head injury in a car accident.Conclusions:The triple regimen of ritonavir-boosted danoprevir plus pegylated-interferonα-2a and ribavirin produced a sustained virologic response rate of 97.1%after 12 weeks treatment in noncirrhotic HCV GT1-infected Chinese patients,and was safe and well tolerated.展开更多
Background and Aims: Chronic hepatitis B virus(HBV)in-fection remains a major public health problem globally.Here,we describe the baseline characteristics and treatment pro-files of HBV-infected patients recruited to ...Background and Aims: Chronic hepatitis B virus(HBV)in-fection remains a major public health problem globally.Here,we describe the baseline characteristics and treatment pro-files of HBV-infected patients recruited to the China Registry of Hepatitis B.Methods: Inclusion criteria were patients with different stages of chronic HBV infection and complete key data.Exclusion criteria were patients with hepatocellular car-cinoma.The baseline clinical,laboratory and treatment pro-files were analyzed.Results: Finally,40,431 patients were included.The median age was 43 years,with 65.2%being men and 51.3%being positive for hepatitis B e antigen(HBeAg).The most common initial diagnosis was chronic hep-atitis B(81.0%),followed by cirrhosis(9.3%),inactive carrier of hepatitis B surface antigen(HBsAg)(6.7%),and immune tolerant phase of hepatitis B infection(3.0%).Among the 21,228 patients who were on treatment,88.0%,10.0%and 2.0%received nucleos(t)ide analogues(NAs),interferon or combination of NAs and interferon,respectively.The propor-tion of patients who received preferred NAs(entecavir or te-nofovir disoproxil fumarate)had increased from 13.5%in 2003 to 79.7%in 2016.Conclusions: We concluded that middle-aged men accounted for most of the patients with chronic hepatitis B in this cross-sectional study.About half of the patients were HBeAg-positive.NAs were the most com-monly used therapy,and use of the preferred NAs had steadily increased in the past decade.展开更多
This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading ef...This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading effects of generators,carbon tax,and prohibited operating zones of generators,respectively.ASHLO algorithm,involves random learning operator,individual learning operator,social learning operator and adaptive strategies.To compare and analyze the computation performance of the ASHLO method,the proposed ASHLO method and other heuristic intelligent optimization methods are employed to solve OPF problem on the modified IEEE 30-bus and 118-bus AC/DC hybrid test system.Numerical results indicate that the ASHLO method has good convergent property and robustness.Meanwhile,the impacts of wind speeds and locations of HVDC transmission line integrated into the AC network on the OPF results are systematically analyzed.展开更多
With the proliferation of renewable energy and electric vehicles(EVs),there have been increasing uncertainties in power systems.Identifying the influencing random variables will reduce the effort in uncertainty modeli...With the proliferation of renewable energy and electric vehicles(EVs),there have been increasing uncertainties in power systems.Identifying the influencing random variables will reduce the effort in uncertainty modeling and improve the controllability of power systems.In this paper,a density-based global sensitivity analysis(GSA)method is proposed to evaluate the influence of uncertainties on islanded microgrids(IMGs).Firstly,the maximum IMG loadability evaluation model is established to assess the distance from the current operation point to the critical operation point.Secondly,the Borgonovo method,which is a density-based GSA method,is used to evaluate the influence of input variables on IMG loadability.Thirdly,to improve GSA efficiency,a modified Kriging model is used to obtain a surrogate model of IMG loadability,and Borgonovo indices are calculated based on the surrogate model.Finally,the proposed method is tested on a 38-bus IMG system.Simulation results are compared with those considering other methods to validate the effectiveness of the proposed method.Energy storage systems are considered to diminish the influence of critical uncertainties on IMG operation.展开更多
Transmission network expansion can significantly improve the penetration level of renewable generation.However,existing studies have not explicitly revealed and quantified the trade-off between the investment cost and...Transmission network expansion can significantly improve the penetration level of renewable generation.However,existing studies have not explicitly revealed and quantified the trade-off between the investment cost and penetration level of renewable generation.This paper proposes a distributionally robust optimization model to minimize the cost of transmission network expansion under uncertainty and maximize the penetration level of renewable generation.The proposed model includes distributionally robust joint chance constraints,which maximize the minimum expectation of the renewable utilization probability among a set of certain probability distributions within an ambiguity set.The proposed formulation yields a twostage robust optimization model with variable bounds of the uncertain sets,which is hard to solve.By applying the affine decision rule,second-order conic reformulation,and duality,we reformulate it into a single-stage standard robust optimization model and solve it efficiently via commercial solvers.Case studies are carried on the Garver 6-bus and IEEE 118-bus systems to illustrate the validity of the proposed method.展开更多
This paper proposes a data-driven topology identification method for distribution systems with distributed energy resources(DERs).First,a neural network is trained to depict the relationship between nodal power inject...This paper proposes a data-driven topology identification method for distribution systems with distributed energy resources(DERs).First,a neural network is trained to depict the relationship between nodal power injections and voltage magnitude measurements,and then it is used to generate synthetic measurements under independent nodal power injections,thus eliminating the influence of correlated nodal power injections on topology identification.Second,a maximal information coefficient-based maximum spanning tree algorithm is developed to obtain the network topology by evaluating the dependence among the synthetic measurements.The proposed method is tested on different distribution networks and the simulation results are compared with those of other methods to validate the effectiveness of the proposed method.展开更多
With the continuous development of the spot market,in the multi-stage power market environment with the day-ahead market and right market,the study associated with the portfolio of energy storage devices requires that...With the continuous development of the spot market,in the multi-stage power market environment with the day-ahead market and right market,the study associated with the portfolio of energy storage devices requires that attention should be paid to transmission congestion and power congestion.To maximize the profit of energy storage and avoid the imbalance of power supply and consumption and the risk of node price fluctuation caused by transmission congestion,this paper presents a portfolio strategy of energy storage devices with financial/physical contracts.First,the concepts of financial/physical transmission rights and financial/physical storage rights are proposed.Then,the portfolio models of financial contract and physical contract are established with the conditional value-at-risk to measure the risks.Finally,the portfolio models are verified through the test data of the Pennsylvania-New Jersey-Maryland(PJM)electric power spot market,and the comparison between the risk aversion of portfolios based on financial/physical contract with the portfolio of the market without rights.The simulation results show that the portfolio models proposed in this paper can effectively avoid the risk of market price fluctuations.展开更多
文摘To facilitate the achieving of the goal of“eliminating viral hepatitis as a major public health threat by 2030”set by the World Health Organization,the Chinese Society of Hepatology together with the Chinese Society of Infectious Diseases(both are branches of the Chinese Medical Association)organized a panel of experts and updated the guidelines for prevention and treatment of chronic hepatitis B in China(version 2022).With the support of available evidence,this revision of the guidelines focuses on active prevention,large scale testing,and expansion of therapeutic indication of chronic hepatitis B with the aim of reducing the hepatitis B related disease burden.
文摘In 2015, the Chinese Society of Hepatology and the Chinese Society of Gastroenterology published a consensus on pri-mary biliary cholangitis (PBC). In the past years, numerous clinical studies have been published in the field of PBC. To guide the clinical diagnosis and management of PBC patients, the Chinese Society of Hepatology invited a panel of experts to assess the new clinical evidence and formulate the current guidelines.
基金supported by the National Natural Science Foundation of China (No.U2166201)China Postdoctoral Science Foundation (No.2022TQ0206)。
文摘The National Electricity Market(NEM)in Australia was suspended during June 15-23,2022,with a primary attribution to the lack of available generation capacity.This incident is noteworthy because it was the first market suspension in NEM’s history and took place in a major energy exporting country.In this letter,we review the outline and impacts of the incident.From the perspectives of market regulation,electricity supply,and electricity demand,we identify three underlying causes of the market suspension and offer four recommendations for the market mechanism evolution to ensure power supply security.
基金supported by the Science and Technology Project of State Grid Corporation of China“Research on the mechanisms and key technologies of the provincial financial transmission right market under the unified load-side pricing model”。
文摘Increasing penetration of renewable energy generation poses a challenge to power system inertia adequacy.It is vital to provide long-term incentive signals to induce a generation mix with adequate inertia supply.However,existing literature rarely studies inertia incentive mechanisms or considers inertia constraints when making generation investment decisions.Thus,we propose an inertia market to quantify the value of inertia and to remunerate inertia provision.To examine the impacts of the inertia market on generation mix,we then propose a stochastic bilevel generation investment equilibrium model that depicts a multi-leader and multi-follower Stackelberg game.The lower level of the model considers the proposed inertia market,along with the energy,reserve,and capacity markets.The upper level considers multiple profit-maximizing strategic producers,and each producer is able to build gas-fired generators,wind generators,and energy storages.Numerical experiments demonstrate that a generation mix with adequate inertia supply can be induced with the proposed inertia market whereas there can be inertia shortage without the inertia market.Interestingly,considering carbon taxes,it is more cost-competitive to invest in wind resources with virtual inertia facilities than to substitute wind resources by thermal generators.Correspondingly,the introduction of an inertia market does not significantly reduce wind generation shares but boosts virtual inertia facility penetration.Our findings imply a future power system powered by fully decarbonized power resources with adequate inertia.
文摘To facilitate the achieving of the goal of“eliminating viral hepatitis as a major public health threat by 2030”set by theWorld Health Organization,the Chinese Society of Hepatology together with the Chinese Society of Infectious Diseases(both are branches of the ChineseMedical Association)organized a panel of experts and updated the guidelines for prevention and treatment of chronic hepatitis B in China(version 2022).With the support of available evidence,this revision of the guidelines focuses on active prevention,large-scale testing,and expansion of therapeutic indication of chronic hepatitis B with the aim of reducing the hepatitis B–related disease burden.
基金Ascletis BioScience Co.,Ltd.provided financial support for this study
文摘Background and Aims:Ravidasvir(RDV)is a new generation pangenotypic hepatitis C virus(HCV)NS5A inhibitor,with high barrier to baseline resistance-associated species.This is the first phase 2/3 study conducted in China's Mainland confirming the efficacy and safety of RDV+ritonavir-boosted danoprevir+ribavirin for 12 weeks in treatment-naive noncirrhotic patients with genotype 1 infection in a large population.Methods:In this multicenter,randomized,doubleblinded,placebo-controlled phase 2/3 trial(NCT03362814),we enrolled 424 treatment-nafve,noncirrhotic adult HCV genotype 1 patients.All patients were randomized at 3∶1 ratio to receive a combination of RDV 200mg once daily plus ritonavir-boosted danoprevir 100mg/100mg twice daily and oral ribavirin 1000/1200mg/day(body weight<75/≥75 kg)(n=318)or placebo(n=106)for 12 weeks.The primary end-point was the rate of sustained virologic response 12 weeks after the end of treatment,and the safety was evaluated and compared between treatment and placebo groups.Results:The overall rate of sustained virological response at 12 weeks after treatment is 99%(306/309,95%,CI:97%-100%)under per protocol set analysis.All patients harboring baseline NS5A resistance-associated species in the treatment group(76/76,per protocol set)achieved sustained virological response at 12 weeks after treatment.No treatment-related serious adverse events were reported.Laboratory abnormalities showed mild or moderate severity(grade 1 and grade 2)in liver function tests.Conclusions:In treatment-na(i)ve,noncirrhotic HCV Chinese patients infected with HCV genotype 1,all-oral regimen of RDV+ritonavir-boosted danoprevir+ribavirin for 12 weeks was highly efficacious,safe,and well tolerated.
基金Ascletis Pharmaceuticals Co.,Ltd.provided financial support for this study(MANASA)
文摘Background and Aims:Genotype(GT)1 remains the predominant hepatitis c virus(HCV)GT in Chinese patients.Over 80%of those Chinese patients harbor the interferon-sensitive CC allele of IFNL4rs12979860,which is favorable for interferon-based treatment regimens.This phaseⅢclinical trial aimed to evaluate the efficacy and safety of the ritonavirboosted danoprevir plus pegylated-interferonα-2a and ribavirin regimen for 12 weeks in treatment-na(i)ve mainland Chinese patients infected with HCV GT1 without cirrhosis.Methods:One hundred and forty-one treatment-na(i)ve,non-cirrhotic HCV GT1 Chinese patients(age≥18 years)were enrolled for this single-arm,multicenter,phaseⅢMANASA study(NCT03020082).Patients received a combination of ritonavir-boosted danoprevir(100 mg/100 mg)twice a day plus subcutaneous injection of weekly pegylated-interferonα-2a(180μg)and oral ribavirin(1000/1200 mg/day body weight<75/≥75 kg)for 12 weeks.The primary end-point was sustained virologic response rate at 12 weeks after the end of treatment.The secondary end-points were safety outcomes,tolerability,virologic response over time and relapse rate.Results:All enrolled patients were HCV GT1-infected,and most among them(97.9%,123/141)had the HCV GT1b subtype.Single-nucleotide polymorphism test showed that the majority of patients were of the IFNL4 rs12979860 CC genotype(87.2%,123/141).Overall,140 patients completed the 12-week treatment,and 97.1%(136/140)patients achieved sustained virologic response at 12 weeks(per protocol population group,95%confidence interval:92.9-99.2%).Only drug-related serious adverse event occurred.Most of the adverse events were grade 1 and grade 2 alanine aminotransferase elevation or liver dysfunction.One patient discontinued treatment because of severe head injury in a car accident.Conclusions:The triple regimen of ritonavir-boosted danoprevir plus pegylated-interferonα-2a and ribavirin produced a sustained virologic response rate of 97.1%after 12 weeks treatment in noncirrhotic HCV GT1-infected Chinese patients,and was safe and well tolerated.
文摘Background and Aims: Chronic hepatitis B virus(HBV)in-fection remains a major public health problem globally.Here,we describe the baseline characteristics and treatment pro-files of HBV-infected patients recruited to the China Registry of Hepatitis B.Methods: Inclusion criteria were patients with different stages of chronic HBV infection and complete key data.Exclusion criteria were patients with hepatocellular car-cinoma.The baseline clinical,laboratory and treatment pro-files were analyzed.Results: Finally,40,431 patients were included.The median age was 43 years,with 65.2%being men and 51.3%being positive for hepatitis B e antigen(HBeAg).The most common initial diagnosis was chronic hep-atitis B(81.0%),followed by cirrhosis(9.3%),inactive carrier of hepatitis B surface antigen(HBsAg)(6.7%),and immune tolerant phase of hepatitis B infection(3.0%).Among the 21,228 patients who were on treatment,88.0%,10.0%and 2.0%received nucleos(t)ide analogues(NAs),interferon or combination of NAs and interferon,respectively.The propor-tion of patients who received preferred NAs(entecavir or te-nofovir disoproxil fumarate)had increased from 13.5%in 2003 to 79.7%in 2016.Conclusions: We concluded that middle-aged men accounted for most of the patients with chronic hepatitis B in this cross-sectional study.About half of the patients were HBeAg-positive.NAs were the most com-monly used therapy,and use of the preferred NAs had steadily increased in the past decade.
基金supported by National Natural Science Foundation of China(No.51377103)the technology project of State Grid Corporation of China:Research on Multi-Level Decomposition Coordination of the Pareto Set of Multi-Objective Optimization Problem in Bulk Power System(No.SGSXDKYDWKJ2015-001)the support from State Energy Smart Grid R&D Center(SHANGHAI)
文摘This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading effects of generators,carbon tax,and prohibited operating zones of generators,respectively.ASHLO algorithm,involves random learning operator,individual learning operator,social learning operator and adaptive strategies.To compare and analyze the computation performance of the ASHLO method,the proposed ASHLO method and other heuristic intelligent optimization methods are employed to solve OPF problem on the modified IEEE 30-bus and 118-bus AC/DC hybrid test system.Numerical results indicate that the ASHLO method has good convergent property and robustness.Meanwhile,the impacts of wind speeds and locations of HVDC transmission line integrated into the AC network on the OPF results are systematically analyzed.
基金supported by National Natural Science Foundation of China(No.51707115).
文摘With the proliferation of renewable energy and electric vehicles(EVs),there have been increasing uncertainties in power systems.Identifying the influencing random variables will reduce the effort in uncertainty modeling and improve the controllability of power systems.In this paper,a density-based global sensitivity analysis(GSA)method is proposed to evaluate the influence of uncertainties on islanded microgrids(IMGs).Firstly,the maximum IMG loadability evaluation model is established to assess the distance from the current operation point to the critical operation point.Secondly,the Borgonovo method,which is a density-based GSA method,is used to evaluate the influence of input variables on IMG loadability.Thirdly,to improve GSA efficiency,a modified Kriging model is used to obtain a surrogate model of IMG loadability,and Borgonovo indices are calculated based on the surrogate model.Finally,the proposed method is tested on a 38-bus IMG system.Simulation results are compared with those considering other methods to validate the effectiveness of the proposed method.Energy storage systems are considered to diminish the influence of critical uncertainties on IMG operation.
基金supported by the National Natural Science Foundation of China(No.52077136)。
文摘Transmission network expansion can significantly improve the penetration level of renewable generation.However,existing studies have not explicitly revealed and quantified the trade-off between the investment cost and penetration level of renewable generation.This paper proposes a distributionally robust optimization model to minimize the cost of transmission network expansion under uncertainty and maximize the penetration level of renewable generation.The proposed model includes distributionally robust joint chance constraints,which maximize the minimum expectation of the renewable utilization probability among a set of certain probability distributions within an ambiguity set.The proposed formulation yields a twostage robust optimization model with variable bounds of the uncertain sets,which is hard to solve.By applying the affine decision rule,second-order conic reformulation,and duality,we reformulate it into a single-stage standard robust optimization model and solve it efficiently via commercial solvers.Case studies are carried on the Garver 6-bus and IEEE 118-bus systems to illustrate the validity of the proposed method.
基金supported by the National Key R&D Program of China(No.2017YFB0902800)the National Natural Science Foundation of China(Grant No.52077136).
文摘This paper proposes a data-driven topology identification method for distribution systems with distributed energy resources(DERs).First,a neural network is trained to depict the relationship between nodal power injections and voltage magnitude measurements,and then it is used to generate synthetic measurements under independent nodal power injections,thus eliminating the influence of correlated nodal power injections on topology identification.Second,a maximal information coefficient-based maximum spanning tree algorithm is developed to obtain the network topology by evaluating the dependence among the synthetic measurements.The proposed method is tested on different distribution networks and the simulation results are compared with those of other methods to validate the effectiveness of the proposed method.
文摘With the continuous development of the spot market,in the multi-stage power market environment with the day-ahead market and right market,the study associated with the portfolio of energy storage devices requires that attention should be paid to transmission congestion and power congestion.To maximize the profit of energy storage and avoid the imbalance of power supply and consumption and the risk of node price fluctuation caused by transmission congestion,this paper presents a portfolio strategy of energy storage devices with financial/physical contracts.First,the concepts of financial/physical transmission rights and financial/physical storage rights are proposed.Then,the portfolio models of financial contract and physical contract are established with the conditional value-at-risk to measure the risks.Finally,the portfolio models are verified through the test data of the Pennsylvania-New Jersey-Maryland(PJM)electric power spot market,and the comparison between the risk aversion of portfolios based on financial/physical contract with the portfolio of the market without rights.The simulation results show that the portfolio models proposed in this paper can effectively avoid the risk of market price fluctuations.