AIM： To determine factors related to disease severity, mortality and morbidity in acute pancreatitis.METHODS： One hundred and ninety-nine consecutive patients were admitted with the diagnosis of acute pancreatitis ...AIM： To determine factors related to disease severity, mortality and morbidity in acute pancreatitis.METHODS： One hundred and ninety-nine consecutive patients were admitted with the diagnosis of acute pancreatitis （AP） in a 5-year period （1998-2002）. In a prospective design, demographic data, etiology, mean hospital admission time, clinical, radiological, biochemical findings, treatment modalities, mortality and morbidity were recorded. Endocrine insufficiency was investigated with oral glucose tolerance test. The relations between these parameters, scoring systems （Ranson, Imrie and APACHE Ⅱ） and patients＇ outcome were determined by using invariable tests and the receiver operating characteristics curve.RESULTS： One hundred patients were men and 99 were women; the mean age was 55 years. Biliary pancreatitis was the most common form, followed by idiopathic pancreatitis （53% and 26%, respectively）. Sixty-three patients had severe pancreatitis and 136 had mild disease. Respiratory rate 〉 20/min, pulse rate 〉 90min, increased C-reactive protein （CRP）, lactate dehydrogenase （LDH） and aspartate aminotransferase （AST） levels, organ necrosis 〉 30% on computed tornography （CT） and leukocytosis were associated with severe disease. The rate of glucose intolerance, morbidity and mortality were 24.1%, 24.8% and 13.6%, respectively. CRP 〉 142 mg/L, BUN 〉 22 mg/dL, LDH 〉 667 U/L, base excess 〉 -5, CT severity index 〉 3 and APACHE score 〉 8 were related to morbidity and mortality.CONCLUSION： APACHE Ⅱ score, LDH, base excess and CT severity index have prognostic value and CRP is a reliable marker for predicting both mortality and morbidity.展开更多
Objective:Our aim was to prospectively compare the Accuracy of Acute Physiology and Chronic Health Evaluation(APACHE)II,Bedside Index of Severity in Acute Pancreatitis(BISAP),Ranson’s score and modified Computed Tomo...Objective:Our aim was to prospectively compare the Accuracy of Acute Physiology and Chronic Health Evaluation(APACHE)II,Bedside Index of Severity in Acute Pancreatitis(BISAP),Ranson’s score and modified Computed Tomography Severity Index(CTSI)in predicting the severity of acute pancreatitis based on Atlanta 2012 definitions in a tertiary care hospital in northern India.Methods:Fifty patients with acute pancreatitis admitted to our hospital during the period of March 2015 to September 2016 were included in the study.APACHE II,BISAP and Ranson’s score were calculated for all the cases.Modified CTSI was also determined based on a pancreatic protocol contrast enhanced computerized tomography(CT).Optimal cut-offs for these scoring systems and the area under the curve(AUC)were evaluated based on the receiver operating characteristics(ROC)curve and these scoring systems were compared prospectively.Results:Of the 50 cases,14 were graded as severe acute pancreatitis.Pancreatic necrosis was present in 15 patients,while 14 developed persistent organ failure and 14 needed intensive care unit(ICU)admission.The AUC for modified CTSI was consistently the highest for predicting severe acute pancreatitis(0.919),pancreatic necrosis(0.993),organ failure(0.893)and ICU admission(0.993).APACHE II was the second most accurate in predicting severe acute pancreatitis(AUC 0.834)and organ failure(0.831).APACHE II had a high sensitivity for predicting pancreatic necrosis(93.33%),organ failure(92.86%)and ICU admission(92.31%),and also had a high negative predictive value for predicting pancreatic necrosis(96.15%),organ failure(96.15%)and ICU admission(95.83%).Conclusion:APACHE II is a useful prognostic scoring system for predicting the severity of acute pancreatitis and can be a crucial aid in determining the group of patients that have a high chance of need for tertiary care during the course of their illness and therefore need early resuscitation and prompt referral,especially in resource-limited developing countries.展开更多
AIM： Acute pancreatitis （AP） is a process with variable involvement of regional tissues or organ systems. Multifactorial scales included the Ranson, Acute Physiology and Chronic Health Evaluation （APACHE Ⅱ） syst...AIM： Acute pancreatitis （AP） is a process with variable involvement of regional tissues or organ systems. Multifactorial scales included the Ranson, Acute Physiology and Chronic Health Evaluation （APACHE Ⅱ） systems and Balthazar computed tomography severity index （CTSI）. The purpose of this review study was to assess the accuracy of CTSI, Ranson score, and APACHE II score in course and outcome prediction of AP. METHODS： We reviewed 121 patients who underwent helical CT within 48 h after onset of symptoms of a first episode of AP between 1999 and 2003. Fourteen inappropriate subjects were excluded; we reviewed the 107 contrastenhanced CT images to calculate the CTSI. We also reviewed their Ranson and APACHE Ⅱ score. In addition, complications, duration of hospitalization, mortality rate, and other pathology history also were our comparison parameters. RESULTS： We classified 85 patients （79%） as having mild AP （CTSI 〈5） and 22 patients （21%） as having severe AP （CTSI ≥5）. In mild group, the mean APACHE II score and Ranson score was 8.6±1.9 and 2.4±1.2, and those of severe group was 10.2±2.1 and 3.1±0.8, respectively. The most common complication was pseudocyst and abscess and it presented in 21 （20%） patients and their CTSI was 5.9±1.4. A CTSI ≥5 significantly correlated with death, complication present, and prolonged length of stay. Patients with a CTSI ≥5 were 15 times to die than those CTSI 〈5, and the prolonged length of stay and complications present were 17 times and 8 times than that in CTSI 〈5, respectively. CONCLUSION： CTSI is a useful tool in assessing the severity and outcome of AP and the CTSI ≥5 is an index in our study. Although Ranson score and APACHE II score also are choices to be the predictors for complications, mortality and the length of stay of AP, the sensitivity of them are lower than CTSI.展开更多
AIM:The generation of oxygen free radicals has been implicated in the pathogenesis of experimental pancreatitis. The aim of this study was to determine the role of oxygen free radicals in patients with acute pancreati...AIM:The generation of oxygen free radicals has been implicated in the pathogenesis of experimental pancreatitis. The aim of this study was to determine the role of oxygen free radicals in patients with acute pancreatitis. METHODS:The plasma levels of C-reactive protein(CRP), lipid peroxide(LPO),myeloperoxidase(MPO)and superoxide dismutase(SOD)were measured in 13 patients with acute pancreatitis and 14 healthy volunteers. RESULTS:Among the patients with acute pancreatitis,there were higher plasma levels of LPO and MPO and lower SOD activity in patients with severe pancreatitis than in those with mild pancreatitis.However,there was no significant difference in the serum marker of oxidative stress no matter what the etiology was.The LPO level was especially correlated with the concentration of serum CRP and CT severity index. CONCLUSION:The oxygen free radicals may be closely associated with inflammatory process and the severity of acute pancreatitis.Especially,the concentration of plasma LPO is a meaningful index for determining the severity of the disease.展开更多
AIM： To determine factors affecting the outcome of patients with cirrhosis undergoing surgery and to compare the capacities of the Child-Turcotte-Pugh （CTP） and model for end-stage liver disease （MELD） score to p...AIM： To determine factors affecting the outcome of patients with cirrhosis undergoing surgery and to compare the capacities of the Child-Turcotte-Pugh （CTP） and model for end-stage liver disease （MELD） score to predict that outcome. METHODS： We reviewed the charts of 195 patients with cirrhosis who underwent surgery at two teaching hospitals over a five-year period. The combined endpoint of death or hepatic decompensation was considered to be the primary endpoint. RESULTS： Patients who reached the endpoint had a higher MELD score, a higher CTP score and were more likely to have undergone an urgent procedure. Among patients undergoing elective surgical procedures, no statistically significant difference was noted in the mean MELD （12.8 ＋ 3.9 vs 12.6 ＋ 4.7, P = 0.9） or in the mean CTP （7.6 ± 1.2 vs 7.7 ± 1.7, P = 0.8） between patients who reached the endpoint and those who did not. Both mean scores were higher in the patients reaching the endpoint in the case of urgent procedures （MELD： 22.4 ± 8.7 vs 15.2 ± 6.4, P = 0.0007; CTP： 9.9 ± 1.8 vs 8.5 ± 1.8, P = 0.008）. The performances of the MELD and CTP scores in predicting the outcome of urgent surgery were only fair, without a significant difference between them （AUC = 0.755 ± 0.066 for MELD vs AUC = 0.696 ± 0.070 for CTP, P = 0.3）. CONCLUSION： The CTP and MELD scores performed equally, but only fairly in predicting the outcome of urgent surgical procedures. Larger studies are needed to better define the factors capable of predicting the outcome of elective surgical procedures in patients with cirrhosis.equally, but only fairly in predicting the outcome of urgent surgical procedures. Larger studies are needed to better define the factors capable of predicting the outcome of elective surgical procedures in patients with cirrhosis.展开更多
AIM: To evaluate the relationship between the expression of lipopolysaccharides (LPS) binding protein (LBP) and CD14 mRNA and the severity of liver injury in alcohol-fed rats. METHODS: Twenty Wistar rats were divided ...AIM: To evaluate the relationship between the expression of lipopolysaccharides (LPS) binding protein (LBP) and CD14 mRNA and the severity of liver injury in alcohol-fed rats. METHODS: Twenty Wistar rats were divided into two groups:ethanol-fed group (group E) and control group (group C). Group E was fed with ethanol(5-12 g x kg(-1) x d(-1)) and group C received dextrose instead of ethanol. Rats of the two groups were sacrificed at 4 weeks and 8 weeks. Levels of endotoxin and alanine transaminase (ALT) in blood were measured, and liver pathology was observed under light and electronic microscopy. Expressions of LBP and CD14 mRNA in liver tissues were determined by RT-PCR analysis. RESULTS: Plasma endotoxin levels were increased more significantly in group E(129+/-21) ng x L(-1) and (187+/-35) ng x L(-1) at 4 and 8 wk than in control rats(48+/-9) ng x L(-1) and (53+/-11) ng x L(-1), respectively (P【0.05). Mean values of plasma ALT levels were (1867+/-250) nkat x L(-1) and (2450+/-367) nkat x L(-1) in Group E. The values were increased more dramatically in ethanol-fed rats than in Group C after 4 and 8 weeks. In liver section from ethanol-fed rats, there were marked pathological changes (steatosis, cell infiltration and necrosis). In ethanol-fed rats, ethanol administration led to a significant increase in LBP and CD14 mRNA levels compared with the control group (P【0.05). CONCLUSION: Ethanol administration led to a significant increase in endotoxin levels in serum and LBP and CD14 mRNA expressions in liver tissues. The increase of LBP and CD14 mRNA expression might wake the liver more sensitive to endotoxin and liver injury.展开更多
AIM:The significance of hepatitis C virus (HCV) serum titers has been examined in several clinical situations. There is much evidence that patients with a lower viral load have better response rates to anti-viral ther...AIM:The significance of hepatitis C virus (HCV) serum titers has been examined in several clinical situations. There is much evidence that patients with a lower viral load have better response rates to anti-viral therapy compared to those with higher levels.Moreover,a direct association has been observed between serum titers of HCV and transmission rates of the virus.The aim of the present study was to determine if there was any correlation between HCV viral load and the severity of liver disease. METHODS:Fifty patients with HCV infection were included in the study.These comprised of 34 subjects with a history of alcohol use and 16 non-alcoholics.Quantitative serum HCV RNA assay was carried out using the branched DNA (bDNA) technique.Linear regression analysis was performed between serum viral titers and liver tests.In addition,for the purpose of comparison,the subjects were divided into two groups:those with low viral liters (≤50 genome mEq/mL) and high titers (>50 mEq/mL). RESULTS:All subjects were men,with a mean±SD age of 47±7.8 years.The mean HCV RNA level in the blood was 76.3×10~5±109.1 genome equivalents/mL.There was no correlation between HCV RNA levels and age of the patients (r=0.181),and the history or amount (g/d) of alcohol consumption (r=0.07).Furthermore,no correlation was observed between serum HCV RNA levels and the severity of liver disease as judged by the values of serum albumin (r=0.175),bilirubin (r=0.217),ALT (r=0.06) and AST (r=0.004) levels.Similarly,no significant difference was observed between patients with low viral titers and high liters with respect to any of the parameters. CONCLUSION:Our results indicate that the severity of liver disease is independent of serum levels of hepatitis C virus.These findings are important since they have a direct impact on the current debate regarding the role of direct cytopathic effect of hepatitis C virus versus immune-mediated injury in the pathogenesis of HCV-related liver damage.展开更多
为了衡量电压暂降对用电设备的影响和指导电压暂降补偿方案的设计,须评估电压暂降对负荷影响的严重程度。分析了多次电压暂降在时间尺度上的集聚效应,针对用电设备修复时间内的多次非规则电压暂降,将其电压时序曲线转换为电压持续曲线,...为了衡量电压暂降对用电设备的影响和指导电压暂降补偿方案的设计,须评估电压暂降对负荷影响的严重程度。分析了多次电压暂降在时间尺度上的集聚效应,针对用电设备修复时间内的多次非规则电压暂降,将其电压时序曲线转换为电压持续曲线,定义了多次电压暂降的平均越限持续时间差和越限率;对比了多种常规严重度指标的优劣,将电压暂降经历的多个持续时间区间敏感度相叠加,构建更加精细的改进电压暂降严重度指标,与多次电压暂降的电压持续曲线结合,形成多次电压暂降严重度评估方法。某110 k V变电站和IEEE1159.2测试数据的仿真结果验证了所提方法的正确性。展开更多
文摘AIM： To determine factors related to disease severity, mortality and morbidity in acute pancreatitis.METHODS： One hundred and ninety-nine consecutive patients were admitted with the diagnosis of acute pancreatitis （AP） in a 5-year period （1998-2002）. In a prospective design, demographic data, etiology, mean hospital admission time, clinical, radiological, biochemical findings, treatment modalities, mortality and morbidity were recorded. Endocrine insufficiency was investigated with oral glucose tolerance test. The relations between these parameters, scoring systems （Ranson, Imrie and APACHE Ⅱ） and patients＇ outcome were determined by using invariable tests and the receiver operating characteristics curve.RESULTS： One hundred patients were men and 99 were women; the mean age was 55 years. Biliary pancreatitis was the most common form, followed by idiopathic pancreatitis （53% and 26%, respectively）. Sixty-three patients had severe pancreatitis and 136 had mild disease. Respiratory rate 〉 20/min, pulse rate 〉 90min, increased C-reactive protein （CRP）, lactate dehydrogenase （LDH） and aspartate aminotransferase （AST） levels, organ necrosis 〉 30% on computed tornography （CT） and leukocytosis were associated with severe disease. The rate of glucose intolerance, morbidity and mortality were 24.1%, 24.8% and 13.6%, respectively. CRP 〉 142 mg/L, BUN 〉 22 mg/dL, LDH 〉 667 U/L, base excess 〉 -5, CT severity index 〉 3 and APACHE score 〉 8 were related to morbidity and mortality.CONCLUSION： APACHE Ⅱ score, LDH, base excess and CT severity index have prognostic value and CRP is a reliable marker for predicting both mortality and morbidity.
文摘Objective:Our aim was to prospectively compare the Accuracy of Acute Physiology and Chronic Health Evaluation(APACHE)II,Bedside Index of Severity in Acute Pancreatitis(BISAP),Ranson’s score and modified Computed Tomography Severity Index(CTSI)in predicting the severity of acute pancreatitis based on Atlanta 2012 definitions in a tertiary care hospital in northern India.Methods:Fifty patients with acute pancreatitis admitted to our hospital during the period of March 2015 to September 2016 were included in the study.APACHE II,BISAP and Ranson’s score were calculated for all the cases.Modified CTSI was also determined based on a pancreatic protocol contrast enhanced computerized tomography(CT).Optimal cut-offs for these scoring systems and the area under the curve(AUC)were evaluated based on the receiver operating characteristics(ROC)curve and these scoring systems were compared prospectively.Results:Of the 50 cases,14 were graded as severe acute pancreatitis.Pancreatic necrosis was present in 15 patients,while 14 developed persistent organ failure and 14 needed intensive care unit(ICU)admission.The AUC for modified CTSI was consistently the highest for predicting severe acute pancreatitis(0.919),pancreatic necrosis(0.993),organ failure(0.893)and ICU admission(0.993).APACHE II was the second most accurate in predicting severe acute pancreatitis(AUC 0.834)and organ failure(0.831).APACHE II had a high sensitivity for predicting pancreatic necrosis(93.33%),organ failure(92.86%)and ICU admission(92.31%),and also had a high negative predictive value for predicting pancreatic necrosis(96.15%),organ failure(96.15%)and ICU admission(95.83%).Conclusion:APACHE II is a useful prognostic scoring system for predicting the severity of acute pancreatitis and can be a crucial aid in determining the group of patients that have a high chance of need for tertiary care during the course of their illness and therefore need early resuscitation and prompt referral,especially in resource-limited developing countries.
文摘AIM： Acute pancreatitis （AP） is a process with variable involvement of regional tissues or organ systems. Multifactorial scales included the Ranson, Acute Physiology and Chronic Health Evaluation （APACHE Ⅱ） systems and Balthazar computed tomography severity index （CTSI）. The purpose of this review study was to assess the accuracy of CTSI, Ranson score, and APACHE II score in course and outcome prediction of AP. METHODS： We reviewed 121 patients who underwent helical CT within 48 h after onset of symptoms of a first episode of AP between 1999 and 2003. Fourteen inappropriate subjects were excluded; we reviewed the 107 contrastenhanced CT images to calculate the CTSI. We also reviewed their Ranson and APACHE Ⅱ score. In addition, complications, duration of hospitalization, mortality rate, and other pathology history also were our comparison parameters. RESULTS： We classified 85 patients （79%） as having mild AP （CTSI 〈5） and 22 patients （21%） as having severe AP （CTSI ≥5）. In mild group, the mean APACHE II score and Ranson score was 8.6±1.9 and 2.4±1.2, and those of severe group was 10.2±2.1 and 3.1±0.8, respectively. The most common complication was pseudocyst and abscess and it presented in 21 （20%） patients and their CTSI was 5.9±1.4. A CTSI ≥5 significantly correlated with death, complication present, and prolonged length of stay. Patients with a CTSI ≥5 were 15 times to die than those CTSI 〈5, and the prolonged length of stay and complications present were 17 times and 8 times than that in CTSI 〈5, respectively. CONCLUSION： CTSI is a useful tool in assessing the severity and outcome of AP and the CTSI ≥5 is an index in our study. Although Ranson score and APACHE II score also are choices to be the predictors for complications, mortality and the length of stay of AP, the sensitivity of them are lower than CTSI.
文摘AIM:The generation of oxygen free radicals has been implicated in the pathogenesis of experimental pancreatitis. The aim of this study was to determine the role of oxygen free radicals in patients with acute pancreatitis. METHODS:The plasma levels of C-reactive protein(CRP), lipid peroxide(LPO),myeloperoxidase(MPO)and superoxide dismutase(SOD)were measured in 13 patients with acute pancreatitis and 14 healthy volunteers. RESULTS:Among the patients with acute pancreatitis,there were higher plasma levels of LPO and MPO and lower SOD activity in patients with severe pancreatitis than in those with mild pancreatitis.However,there was no significant difference in the serum marker of oxidative stress no matter what the etiology was.The LPO level was especially correlated with the concentration of serum CRP and CT severity index. CONCLUSION:The oxygen free radicals may be closely associated with inflammatory process and the severity of acute pancreatitis.Especially,the concentration of plasma LPO is a meaningful index for determining the severity of the disease.
文摘AIM： To determine factors affecting the outcome of patients with cirrhosis undergoing surgery and to compare the capacities of the Child-Turcotte-Pugh （CTP） and model for end-stage liver disease （MELD） score to predict that outcome. METHODS： We reviewed the charts of 195 patients with cirrhosis who underwent surgery at two teaching hospitals over a five-year period. The combined endpoint of death or hepatic decompensation was considered to be the primary endpoint. RESULTS： Patients who reached the endpoint had a higher MELD score, a higher CTP score and were more likely to have undergone an urgent procedure. Among patients undergoing elective surgical procedures, no statistically significant difference was noted in the mean MELD （12.8 ＋ 3.9 vs 12.6 ＋ 4.7, P = 0.9） or in the mean CTP （7.6 ± 1.2 vs 7.7 ± 1.7, P = 0.8） between patients who reached the endpoint and those who did not. Both mean scores were higher in the patients reaching the endpoint in the case of urgent procedures （MELD： 22.4 ± 8.7 vs 15.2 ± 6.4, P = 0.0007; CTP： 9.9 ± 1.8 vs 8.5 ± 1.8, P = 0.008）. The performances of the MELD and CTP scores in predicting the outcome of urgent surgery were only fair, without a significant difference between them （AUC = 0.755 ± 0.066 for MELD vs AUC = 0.696 ± 0.070 for CTP, P = 0.3）. CONCLUSION： The CTP and MELD scores performed equally, but only fairly in predicting the outcome of urgent surgical procedures. Larger studies are needed to better define the factors capable of predicting the outcome of elective surgical procedures in patients with cirrhosis.equally, but only fairly in predicting the outcome of urgent surgical procedures. Larger studies are needed to better define the factors capable of predicting the outcome of elective surgical procedures in patients with cirrhosis.
基金Supported by the National Natural Science Foundation of China(No.39970719).
文摘AIM: To evaluate the relationship between the expression of lipopolysaccharides (LPS) binding protein (LBP) and CD14 mRNA and the severity of liver injury in alcohol-fed rats. METHODS: Twenty Wistar rats were divided into two groups:ethanol-fed group (group E) and control group (group C). Group E was fed with ethanol(5-12 g x kg(-1) x d(-1)) and group C received dextrose instead of ethanol. Rats of the two groups were sacrificed at 4 weeks and 8 weeks. Levels of endotoxin and alanine transaminase (ALT) in blood were measured, and liver pathology was observed under light and electronic microscopy. Expressions of LBP and CD14 mRNA in liver tissues were determined by RT-PCR analysis. RESULTS: Plasma endotoxin levels were increased more significantly in group E(129+/-21) ng x L(-1) and (187+/-35) ng x L(-1) at 4 and 8 wk than in control rats(48+/-9) ng x L(-1) and (53+/-11) ng x L(-1), respectively (P【0.05). Mean values of plasma ALT levels were (1867+/-250) nkat x L(-1) and (2450+/-367) nkat x L(-1) in Group E. The values were increased more dramatically in ethanol-fed rats than in Group C after 4 and 8 weeks. In liver section from ethanol-fed rats, there were marked pathological changes (steatosis, cell infiltration and necrosis). In ethanol-fed rats, ethanol administration led to a significant increase in LBP and CD14 mRNA levels compared with the control group (P【0.05). CONCLUSION: Ethanol administration led to a significant increase in endotoxin levels in serum and LBP and CD14 mRNA expressions in liver tissues. The increase of LBP and CD14 mRNA expression might wake the liver more sensitive to endotoxin and liver injury.
文摘AIM:The significance of hepatitis C virus (HCV) serum titers has been examined in several clinical situations. There is much evidence that patients with a lower viral load have better response rates to anti-viral therapy compared to those with higher levels.Moreover,a direct association has been observed between serum titers of HCV and transmission rates of the virus.The aim of the present study was to determine if there was any correlation between HCV viral load and the severity of liver disease. METHODS:Fifty patients with HCV infection were included in the study.These comprised of 34 subjects with a history of alcohol use and 16 non-alcoholics.Quantitative serum HCV RNA assay was carried out using the branched DNA (bDNA) technique.Linear regression analysis was performed between serum viral titers and liver tests.In addition,for the purpose of comparison,the subjects were divided into two groups:those with low viral liters (≤50 genome mEq/mL) and high titers (>50 mEq/mL). RESULTS:All subjects were men,with a mean±SD age of 47±7.8 years.The mean HCV RNA level in the blood was 76.3×10~5±109.1 genome equivalents/mL.There was no correlation between HCV RNA levels and age of the patients (r=0.181),and the history or amount (g/d) of alcohol consumption (r=0.07).Furthermore,no correlation was observed between serum HCV RNA levels and the severity of liver disease as judged by the values of serum albumin (r=0.175),bilirubin (r=0.217),ALT (r=0.06) and AST (r=0.004) levels.Similarly,no significant difference was observed between patients with low viral titers and high liters with respect to any of the parameters. CONCLUSION:Our results indicate that the severity of liver disease is independent of serum levels of hepatitis C virus.These findings are important since they have a direct impact on the current debate regarding the role of direct cytopathic effect of hepatitis C virus versus immune-mediated injury in the pathogenesis of HCV-related liver damage.
文摘为了衡量电压暂降对用电设备的影响和指导电压暂降补偿方案的设计,须评估电压暂降对负荷影响的严重程度。分析了多次电压暂降在时间尺度上的集聚效应,针对用电设备修复时间内的多次非规则电压暂降,将其电压时序曲线转换为电压持续曲线,定义了多次电压暂降的平均越限持续时间差和越限率;对比了多种常规严重度指标的优劣,将电压暂降经历的多个持续时间区间敏感度相叠加,构建更加精细的改进电压暂降严重度指标,与多次电压暂降的电压持续曲线结合,形成多次电压暂降严重度评估方法。某110 k V变电站和IEEE1159.2测试数据的仿真结果验证了所提方法的正确性。
