This paper presents a technique that increases the second-zone coverage of distance relays without causing overreach problems. The technique is based on the impedance seen by distance relays when faults are simulated ...This paper presents a technique that increases the second-zone coverage of distance relays without causing overreach problems. The technique is based on the impedance seen by distance relays when faults are simulated on the reach of zone-1 relays. The approach checks the relay operation for the maximum as well as the minimum generation outputs of the power system. The proposed technique can be used for different reach setting for zone-1. Results show that it is possible to increase the coverage provided by zone-2 distance relays without causing coordination problems with the primary relays that protect the lines emanating from the remote bus. The proposed method is modified for use in an adaptive protection system. It is shown that further improvements can be achieved when settings are calculated using the proposed method and the prevailing system conditions. The proposed method and its adaptive version were applied to a part of the Power system. The simulation of the system is done by using PSCAD-EMTDC software. The simulated results are observed and compared with the conventional and proposed technique.展开更多
目的探讨慢性阻塞性肺疾病急性加重期(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)患者血清炎症发生区因子2(found in inflammatory zone 2,FIZZ2)和白细胞介素-33(interleukin-33,IL-33)水平变化及与预后的...目的探讨慢性阻塞性肺疾病急性加重期(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)患者血清炎症发生区因子2(found in inflammatory zone 2,FIZZ2)和白细胞介素-33(interleukin-33,IL-33)水平变化及与预后的相关性。方法选取2020年1月~2023年1月中国科学院合肥肿瘤医院收治的102例AECOPD患者为AECOPD组,并根据预后分为生存组(n=30)和死亡组(n=72)。以同期诊治的60例稳定期COPD患者为稳定期组,以同期体检的60例健康人为对照组。采用酶联免疫吸附实验(ELISA)法检测血清FIZZ2和IL-33水平。采用Pearson相关性分析血清FIZZ2和IL-33与肺功能指标的相关性。多因素Logistic回归分析影响AECOPD患者预后的因素。受试者工作特征(ROC)曲线分析血清FIZZ2和IL-33对AECOPD患者预后预测价值。结果AECOPD组血清FIZZ2(212.19±48.47ng/L),IL-33(66.19±13.41μg/L)高于稳定期组(101.11±31.03ng/L,40.69±9.94μg/L)和对照组(42.33±7.65ng/L,26.17±8.10μg/L),差异具有统计学意义(t=15.925,26.915;12.799,20.961,均P<0.05)。血清FIZZ2,IL-33水平与第一秒用力呼气容积占预计值的百分比(forced expiratory volume in one second/predicted value ratio,FEV1%pred)、第一秒用力呼气容积与用力肺活量比值(forced expiratory volume in one second/forced vital capacity,FEV1/FVC)、动脉血氧分压(arterial partial pressure of oxygen,PaO_(2))呈负相关(r=-0.676,-0.707,-0.715;-0.662,-0.711,0.630,均P<0.05),与动脉血二氧化碳分压(arterial carbon dioxide pressure,PaCO_(2))呈正相关(r=0.712,0.689,均P<0.05)。死亡组血清FIZZ2(254.30±53.22 ng/L),IL-33(75.18±15.62μg/L)高于生存组(194.64±47.16 ng/L,62.50±12.37 ng/L),差异具有统计学意义(t=5.604,4.354,均P<0.05)。血清FIZZ2(OR=1.445,95%CI:1.094~1.909),IL-33(OR=1.701,95%CI:1.111~2.602)是影响AECOPD患者预后独立危险因素。血清FIZZ2,IL-33二者联合对AECOPD患者预后的评估的曲线下面积(95%置信区间)为0.886(0.842~0.927),高于各单项指标检测[0.834(0.798~0.890),0.806(0.779~0.846)],差异具有统计学意义(Z=4.255,4.697,均P<0.05)。结论AECOPD患者血清FIZZ2,IL-33水平升高,两者与患者肺功能有关,两者联合检测对AECOPD患者的生存预后具有较高的预测价值。展开更多
文摘This paper presents a technique that increases the second-zone coverage of distance relays without causing overreach problems. The technique is based on the impedance seen by distance relays when faults are simulated on the reach of zone-1 relays. The approach checks the relay operation for the maximum as well as the minimum generation outputs of the power system. The proposed technique can be used for different reach setting for zone-1. Results show that it is possible to increase the coverage provided by zone-2 distance relays without causing coordination problems with the primary relays that protect the lines emanating from the remote bus. The proposed method is modified for use in an adaptive protection system. It is shown that further improvements can be achieved when settings are calculated using the proposed method and the prevailing system conditions. The proposed method and its adaptive version were applied to a part of the Power system. The simulation of the system is done by using PSCAD-EMTDC software. The simulated results are observed and compared with the conventional and proposed technique.
文摘目的探讨慢性阻塞性肺疾病急性加重期(acute exacerbation of chronic obstructive pulmonary disease,AECOPD)患者血清炎症发生区因子2(found in inflammatory zone 2,FIZZ2)和白细胞介素-33(interleukin-33,IL-33)水平变化及与预后的相关性。方法选取2020年1月~2023年1月中国科学院合肥肿瘤医院收治的102例AECOPD患者为AECOPD组,并根据预后分为生存组(n=30)和死亡组(n=72)。以同期诊治的60例稳定期COPD患者为稳定期组,以同期体检的60例健康人为对照组。采用酶联免疫吸附实验(ELISA)法检测血清FIZZ2和IL-33水平。采用Pearson相关性分析血清FIZZ2和IL-33与肺功能指标的相关性。多因素Logistic回归分析影响AECOPD患者预后的因素。受试者工作特征(ROC)曲线分析血清FIZZ2和IL-33对AECOPD患者预后预测价值。结果AECOPD组血清FIZZ2(212.19±48.47ng/L),IL-33(66.19±13.41μg/L)高于稳定期组(101.11±31.03ng/L,40.69±9.94μg/L)和对照组(42.33±7.65ng/L,26.17±8.10μg/L),差异具有统计学意义(t=15.925,26.915;12.799,20.961,均P<0.05)。血清FIZZ2,IL-33水平与第一秒用力呼气容积占预计值的百分比(forced expiratory volume in one second/predicted value ratio,FEV1%pred)、第一秒用力呼气容积与用力肺活量比值(forced expiratory volume in one second/forced vital capacity,FEV1/FVC)、动脉血氧分压(arterial partial pressure of oxygen,PaO_(2))呈负相关(r=-0.676,-0.707,-0.715;-0.662,-0.711,0.630,均P<0.05),与动脉血二氧化碳分压(arterial carbon dioxide pressure,PaCO_(2))呈正相关(r=0.712,0.689,均P<0.05)。死亡组血清FIZZ2(254.30±53.22 ng/L),IL-33(75.18±15.62μg/L)高于生存组(194.64±47.16 ng/L,62.50±12.37 ng/L),差异具有统计学意义(t=5.604,4.354,均P<0.05)。血清FIZZ2(OR=1.445,95%CI:1.094~1.909),IL-33(OR=1.701,95%CI:1.111~2.602)是影响AECOPD患者预后独立危险因素。血清FIZZ2,IL-33二者联合对AECOPD患者预后的评估的曲线下面积(95%置信区间)为0.886(0.842~0.927),高于各单项指标检测[0.834(0.798~0.890),0.806(0.779~0.846)],差异具有统计学意义(Z=4.255,4.697,均P<0.05)。结论AECOPD患者血清FIZZ2,IL-33水平升高,两者与患者肺功能有关,两者联合检测对AECOPD患者的生存预后具有较高的预测价值。
