The Efficacy and Safety of Continuous Popliteal Sciatic Nerve Block for the Relief of Pain Associated with Critical Limb Ischemia: A Retrospective Study

Background: Patients with critical limb ischemia (CLI) often suffer from severe pain. A continuous peripheral nerve block has been shown to provide effective analgesia for patients having lower limb surgery. We have been administering continuous sciatic nerve block (CSNB) for patients with CLI whose pain could not be relieved by other analgesic tools. The aim of this retrospective study was to investigate the efficacy and safety of CSNB for patients with CLI. Method: We retrospectively investigated 99 patients who received CSNB for the relief of severe pain in the lower limb associated with CLI. Patient demographics, neurological history, complications, and subjective evaluation of the effectiveness of CSNB were investigated from their clinical records. The distal tips of 108 catheters were cultured. Result: One hundred and seventy-two catheters were placed in 99 patients. More than 90% of the patients enjoyed considerable relief of severe pain. The analgesic effect of CSNB was greater in patients with older age and hemodialysis. Thirty-one catheters had positive bacterial colonization. However, no severe infectious complication was found. There was no relationship between the co-existence of diabetes and positive bacterial colonization. We encountered a patient with ASO and diabetes who suffered from persistent motor weakness and hypesthesia even after 3 months of CSNB placement. Conclusions: CSNB provided good pain control for patients with severe pain caused by CLI. Although catheters were frequently found to be colonized, infection at the catheter site was self-limiting even in patients with diabetes.

A New One-Twelfth Step Continuous Block Method for the Solution of Modeled Problems of Ordinary Differential Equations

In this paper, we developed a new continuous block method by the method of interpolation and collocation to derive new scheme. We adopted the use of power series as a basis function for approximate solution. We evaluated at off grid points to get a continuous hybrid multistep method. The continuous hybrid multistep method is solved for the independent solution to yield a continuous block method which is evaluated at selected points to yield a discrete block method. The basic properties of the block method were investigated and found to be consistent, zero stable and convergent. The results were found to compete favorably with the existing methods in terms of accuracy and error bound. In particular, the scheme was found to have a large region of absolute stability. The new method was tested on real life problem namely: Dynamic model.

Neoarchaean-Palaeoproterozoic Mafic Dyke Swarms from the Singhbhum Granite Complex,Singhbhum Craton,Eastern India:Implications for Identification of Large Igneous Provinces and Their Possible Continuation on Other Formerly Adjacent Crustal Blocks

The Singhbhum craton of the eastern India consists of the Singhbhum Granite Complex(SGC)and the Chotanagpur Gneissic Complex(CGC)separated by the Singhbhum Mobile Belt(SMB).The CGC is intruded by Mesoproterozoic as well as Cretaceous mafic dykes;in

A Retrospective Comparison of Interscalene Continuous Catheter Verse Single-Injection with Liposomal Bupivacaine in Total Shoulder Arthroplasty

Background: One common method of pain control for total shoulder arthroplasty is long-duration delivery of local anesthetic via interscalene brachial plexus block (ISB) with a continuous catheter. Alternatively, liposomal bupivacaine has also been administered as an ISB as a means to prolong the analgesic effect. This study was completed to measure the non-inferiority of single-injection ISB with liposomal bupivacaine compared with ISB continuous catheter for total shoulder arthroplasty. Methods: We performed a retrospective chart review of patients who underwent total shoulder arthroplasty using either an ISB continuous catheter or a single injection ISB with liposomal bupivacaine for post operative analgesia. The primary goal of this study was to determine if single-injection with liposomal bupivacaine conferred non-inferior pain scores compared to the continuous catheter. Secondary outcomes evaluated oxygen saturation as a measure of hemidiaphragmatic paresis, post operative opioid requirements, and difference in cost. Results: We identified 333 patients for the study: 126 received continuous catheter and 207 received single-injection with liposomal bupivacaine. The median length of stay was 1 day. Pain scores for those treated with single-injection with liposomal bupivacaine were non-inferior to pain scores of those treated with the continuous catheter on post-op days 0, 1 and 2. Pain scores were lower for single-injection with liposomal bupivacaine patients on days 3 and 4, however they did not reach statistical significance. There was no significant difference in oxygen saturation between the two groups. Both groups had similar daily morphine milligram equivalent requirements. Liposomal bupivacaine ISB was also found to be less expensive. Conclusion: Single-injection ISB with liposomal bupivacaine provides non-inferior analgesia at a reduced cost compared with continuous catheter ISB for total shoulder arthroplasty.

Research Progress on Anti-clogging Technology of Submerged Entry Nozzles for Continuous Casting

The causes, the formation process, and the prevention of submerged entry nozzle(SEN) clogging were introduced. The influence of electric field on the SEN clogging was focused on, including the basic theory and measurement of SEN charging,the preliminary research on SEN charging, the influence of molten steel on the wetting behavior of refractory materials in electric field, and the influence of electric field on the oxide inclusions in molten steel. Based on the influence of the hydrodynamics, chemistry and other factors on refractory materials, structure, inclusion particle transfer and adhesion, many anti-clogging researches have been carried out, such as optimizing process conditions, compositing anti-clogging inner lining materials, innovating SEN structure and applying physical fields, which solve the problem of SEN clogging to a certain extent.However, the problems of weak adaptability and superficial study on clogging mechanism are still prominent. The electric field control is a new technology to prevent clogging. Although it has achieved certain results in on-site continuous casting trials,some problems such as the method of applying electric field, the electric field parameters and the equipment still need to be gradually improved, and the surface characteristics of inclusions and SEN materials at high temperatures need to be further studied. It was pointed out that the combination of materials and applied electric field will become an important direction for SEN anti-clogging technology.

Four Steps Continuous Method for the Solution of <i>y″</i>= <i>f</i>(<i>x, y, y′</i>)

This paper proposes a continuous block method for the solution of second order ordinary differential equation. Collocation and interpolation of the power series approximate solution are adopted to derive a continuous implicit linear multistep method. Continuous block method is used to derive the independent solution which is evaluated at selected grid points to generate the discrete block method. The order, consistency, zero stability and stability region are investigated. The new method was found to compare favourably with the existing methods in term of accuracy.

Block Based Bivariate Blending Rational Interpolation via Symmetric Branched Continued Fractions

This paper constructs a new kind of block based bivariate blending rational interpolation via symmetric branched continued fractions. The construction process may be outlined as follows. The first step is to divide the original set of support points into some subsets (blocks). Then construct each block by using symmetric branched continued fraction. Finally assemble these blocks by Newton’s method to shape the whole interpolation scheme. Our new method offers many flexible bivariate blending rational interpolation schemes which include the classical bivariate Newton’s polynomial interpolation and symmetric branched continued fraction interpolation as its special cases. The block based bivariate blending rational interpolation is in fact a kind of tradeoff between the purely linear interpolation and the purely nonlinear interpolation. Finally, numerical examples are given to show the effectiveness of the proposed method.

A Novel Approach to Practical Matrix Converter Motor Drive System With Reverse Blocking IGBT (To continue)

a Pole voltage waveforms (VA20 and VA40) for modulation index 0.4 (middle trace is A-phase voltage waveform) x-axis: 1 div.=10ms, y-axis: 1 div.= 100V b Normalized harmonic spectrum for pole voltage of Fig. 9a c A-phase current and phase voltage for modulation index 0.4 (reference space vector is in inner layer)

复杂结构内爆炸冲击波传播的大规模计算方法研究

为研究爆炸冲击波在矿井巷道等复杂地下密闭空间内的传播过程及衰减规律,提出了一种基于数据流的分块续算方法.该方法解决了计算资源的大量浪费问题,实现了大尺寸复杂地下密闭空间内冲击波传播的大规模、高效率、高精度数值模拟.方形坑道内爆过程的数值结果与实验结果基本一致,证明了该计算方法的准确性.标准模型算例全尺寸计算与分块续算数值模拟结果的误差在0.33%以内,且续算方法在给定算例下相比普通全尺寸计算节约了88.68%的计算核时,证明该方法不仅能保证计算过程的准确性,而且还极大地提高了计算效率.同时,对一个包含长方体型工房和圆柱形分叉泄压洞的大尺寸复杂结构内的爆炸问题进行了数值模拟,结果表明:冲击波超压在泄压洞内是以波动衰减的趋势逐渐减小的,且其衰减速度比在自由场的小;T型分流时管道间采用直角交汇或缩小管道直径在一定程度上有利于冲击波超压的衰减.数值模拟结果表明,基于数据流的分块续算方法可用于地下空间等大尺度复杂结构防爆抗爆设计的理论指导.

分析多模式镇痛下持续髂筋膜间隙阻滞与收肌管阻滞对老年患者全膝关节置换术后快速康复的影响

目的探讨对老年人全膝关节置换术患者在多模式镇痛下分别给予超声引导下持续髂筋膜间隙阻滞以及收肌管阻滞对术后快速康复的影响。方法随机选取2020年2月—2022年11月常州市中医医院收治的60例老年人全膝关节置换术患者为研究对象,以随机数表法分为研究组和参照组,每组30例。参照组在多模式镇痛基础下施以超声引导下持续髂筋膜间隙阻滞,研究组在多模式镇痛基础下施以超声引导下持续收肌管阻滞。对比两组患者动态视觉模拟评分法(Visual Analogue Scale,VAS)评分、术后各时间点静息状态VAS评分、美国特种外科医院膝关节评分量表(Hospital for Special Surgery Knee Score,HSS)评分以及膝关节关节活动度(Range of Motion,ROM)。结果术后6、12、24、48 h,两组VAS评分比较,差异无统计学意义(P均>0.05)。研究组HSS评分为(71.25±7.25)分,高于参照组的(63.55±6.79)分,差异有统计学意义(t=4.246,P<0.05)。术后3、7、10、12 d,研究组ROM均高于参照组,差异有统计学意义(P均<0.05)。结论临床对老年人全膝关节置换术患者在给予镇痛干预期间,同超声引导下持续髂筋膜间隙阻滞比较,超声引导下持续收肌管阻滞方法的有效应用,可对患者的术后早期康复给予明显促进。

CT引导下脉冲射频联合连续神经阻滞治疗顽固性带状疱疹后神经痛的临床疗效研究

目的探究CT引导下脉冲射频联合连续神经阻滞治疗顽固性带状疱疹后神经痛(PHN)的临床疗效。方法选取2021年1月至2023年1月本院收治的208例顽固性PHN患者为对象,随机数表法分为联合组和对照组,每组各104例。对照组接受CT引导下脉冲射频治疗,联合组在对照组的基础上行连续硬膜外神经阻滞治疗。比较两组患者不同时间点疼痛情况、临床有效率、镇痛补救情况、睡眠质量,血清高迁移率族蛋白B1(HMGB1)、白细胞介素-1β(IL-1β)和白细胞介素-10(IL-10)水平。结果随访期间,4例患者失访。最终纳入联合组103例,对照组101例。联合组治疗总有效率为89.32%,明显高于对照组的78.22%(P<0.05)。患者疼痛视觉模拟量表(VAS)评分、阿森斯失眠量表(AIS)评分的时间、组间、时间与组间交互效应差异均具有统计学意义(P<0.05);治疗后1、2、4周联合组VAS、AIS评分均低于对照组(P<0.05);联合组镇痛补救次数低于对照组,曲马多使用剂量少于对照组(P<0.05);治疗后4周联合组血清HMGB1、IL-1β、IL-10水平均低于对照组(P<0.05)。结论CT引导下脉冲射频联合连续神经阻滞治疗顽固性PHN,能有效减轻神经炎性损伤,改善患者疼痛症状,提高睡眠质量,其镇痛效果及临床疗效优于单纯使用CT引导下脉冲射频疗法。

足踝手术后连续腓肠肌平面阻滞的镇痛效果

目的 探索连续腓肠肌平面阻滞镇痛用于足踝部手术患者术后镇痛效果。方法选择全麻下行足踝部择期手术患者42例,男19例,女23例,年龄18~64岁,BMI 18~28 kg/m^(2),ASAⅠ—Ⅲ级。将患者随机分为两组:连续腓肠肌平面阻滞镇痛组(CN组)和患者自控静脉镇痛(PCIA)组(Ⅰ组),每组21例。CN组术毕行连续腓肠肌平面阻滞镇痛,配方为0.125%罗哌卡因300 ml,背景剂量为3 ml/h,单次给药剂量为8 ml,锁定时间为25 min。Ⅰ组术毕使用羟考酮PCIA,配方为羟考酮30 mg、托烷司琼6 mg加生理盐水至150 ml,输注速度0.5 ml/h,单次追加剂量5 ml。观察两组术后0~16、16~24、24~48、0~48 h时段静息和活动时NRS评分曲线下面积(AUC),1、8、16、24、32、48 h静息和活动时NRS评分,CN组术后胫神经和腓总神经运动功能恢复时间、羟考酮滴定量、术后48 h内补救镇痛药物的吗啡当量累计使用量、补救镇痛次数、补救镇痛率、首次下床活动时间、术后恶心呕吐的发生情况和患者满意度评分。结果 与Ⅰ组比较,CN组0~16、16~24、24~48、0~48 h静息和活动时NRS评分AUC明显降低(P<0.01),术后1、8、16、24、32、48 h NRS评分明显降低(P<0.01),CN组16 h有10例(50%)患者腓总神经运动功能恢复,24 h有17例(85%)患者腓总神经运动功能恢复,32~48 h所有患者腓总神经运动功能恢复,48 h内所有患者胫神经运动功能正常。与Ⅰ组比较,CN组吗啡当量累计使用量和补救镇痛次数明显减少(P<0.01),补救镇痛率明显降低(P<0.01),患者满意度评分明显升高(P<0.01)。两组羟考酮滴定量、首次下床活动时间,恶心呕吐发生率差异无统计学意义。结论 超声引导下连续腓肠肌平面阻滞可以实现胫神经运动和感觉阻滞分离,可在足踝手术后提供良好且持续的镇痛效果。

收肌管阻滞与单次坐骨神经阻滞联合药物镇痛对全膝关节置换后疼痛的影响

背景:全膝关节置换术是治疗晚期骨关节炎的有效手段,但术后疼痛和关节功能恢复是主要的挑战。神经阻滞和混合药物注射是两种常用的镇痛方法,但其联合应用的效果尚不明确。目的:探讨在全膝关节置换过程中应用超声引导下连续性收肌管阻滞+单次坐骨神经阻滞+“鸡尾酒”混合药物镇痛对患者置换后疼痛缓解以及关节功能恢复的影响。方法:纳入于2022年1-5月河北省沧州中西医结合医院收治的骨关节炎患者120例,随机分为2组(n=60),观察组采用超声引导下连续性收肌管阻滞+单次坐骨神经阻滞+“鸡尾酒”混合药物镇痛,对照组采用超声引导下连续性收肌管阻滞+单次坐骨神经阻滞。比较两组患者在目测类比评分、特种外科医院关节功能评分、疼痛递质、炎症因子表达水平、不良反应发生以及术后徒手肌力方面的差异。结果与结论:①观察组患者在术后6,8,12,24,48,72 h时的静息、运动状态下目测类比评分均低于对照组(P<0.05);②观察组患者在术后1,3个月时的特种外科医院评分显著高于对照组(P<0.05);③在疼痛递质以及炎症因子方面,观察组患者的表达水平要显著低于对照组(P<0.05);④在不良反应以及术后徒手肌力方面,两组之间差异无显著性意义(P>0.05);⑤提示在全膝关节置换过程中应用超声引导连续性收肌管阻滞和单次坐骨神经阻滞的同时,采用“鸡尾酒”混合镇痛药物关节腔注射的方式可以起到很好的镇痛效果,更利于关节功能的恢复,也能缓解术后疼痛以及炎症,同时还具有较高的安全性。

2023年麦收期河南省连阴雨的气候特征和可能成因

2023年麦收期河南省出现了罕见的连阴雨天气,降水和阴雨日数异常偏多,分别为自1961年以来的历史第五位和第二位。分析连阴雨的可能气候成因,主要结论如下:(1)造成连阴雨的环流形势为欧亚中高纬度西高东低,乌拉尔山高压脊持续发展并出现阶段性阻塞,东北冷涡活跃,冷空气能持续南下,西太平洋副热带高压(以下简称副高)偏北、偏强且异常偏西,来自副高西北侧边缘的暖湿气流和冷空气在河南省交汇。(2)副高偏强、偏北、偏西是由偏强、偏北、偏大、偏东的南亚高压和偏强、偏北的东亚副热带西风急流(以下简称西风急流)的引导所致,而东南亚对流层中高层的暖中心偏大、偏北和偏东且呈东西向带状分布,使南亚高压形成了上述的特征。暖中心和东北冷涡的共同作用,使东亚中高层的气温梯度增大,进而加强了西风急流。(3)2023年前期的La Ni1a事件有利于麦收期副高偏北,但不利于副高偏强和明显偏西。麦收期由于台风扰动由泰国湾至菲律宾群岛以东的热带西太平洋对流活跃释放的凝结潜热较多,以及麦收期前期的春季和麦收期伊朗高原至青藏高原的地面感热和潜热较强,使暖中心形成了上述的特征,进而决定了南亚高压和副高的特征。(4)2023年麦收期北大西洋海温偏高,以及北大西洋三极子为负位相,导致了乌拉尔山高压脊持续发展并出现阶段性阻塞,麦收期前期的春季和麦收期伏尔加河至贝加尔湖西北侧地面感热和潜热偏强,而下游贝加尔湖东南侧至鄂霍次克海地面感热和潜热偏弱一定程度上导致上述两区域分别出现了大范围的位势高度正距平和负距平。

床旁超声引导下连续隐神经阻滞联合全身麻醉在老年膝关节置换术中的应用效果及其对定向力、股四头肌肌力的影响

目的探讨床旁超声引导下连续隐神经阻滞联合全身麻醉在老年膝关节置换术中的应用效果及其对定向力、股四头肌肌力的影响。方法回顾性选取2020年11月至2023年11月在延安市人民医院行膝关节置换术的102例老年患者,按照麻醉方法不同分为观察组与对照组,每组各51例。所有患者术中均采取0.3μg/kg舒芬太尼,0.03 mg/kg咪达唑仑,0.3 mg/kg依托咪酯与0.2 mg/kg顺式阿曲库铵进行全身麻醉,对照组术后进行超声引导下连续股神经阻滞,观察组术后进行超声引导下连续隐神经阻滞,麻醉药物均为20 mL 0.2%罗哌卡因,持续阻滞48 h。比较两组患者术后1、4、8、12、24、48 h静息与活动时疼痛数字评分法(NRS)评分,术后3、5及7 d采用Berg平衡量表(BBS)评价其定向力,比较其术后4、6、8、12、24、48 h股四头肌肌力变化,比较两组患者术后1、7 d血清应激反应指标水平,并比较两组患者下床时间及远期膝关节功能。结果两组患者术后1、4、8、12、24、48 h活动时NRS评分与静息时NRS评分比较,差异均无统计学意义(P>0.05)。观察组术后3、5、7 d的BBS评分分别为(37.96±5.21)、(43.06±5.13)、(49.27±3.34)分,均明显高于对照组[(31.91±6.32)、(38.57±4.15)、(41.36±4.44)分],差异均有统计学意义(P<0.05)。术后4 h,两组患者股四头肌肌力比较,差异无统计学意义(P>0.05);观察组术后6、8、12、24、48 h股四头肌肌力分别为(1.95±0.13)、(2.42±0.15)、(2.75±0.41)、(3.11±0.33)、(3.93±0.42)分,均高于对照组[(1.56±0.20)、(2.01±0.13)、(2.14±0.23)、(2.76±0.42)、(3.11±0.35)分],差异均有统计学意义(P<0.05)。术后1 d,两组患者皮质醇、去甲肾上腺素、肾上腺素水平比较,差异均无统计学意义(P>0.05);术后7 d,两组患者皮质醇、去甲肾上腺素、肾上腺素水平均较术后1 d降低,差异均有统计学意义(P<0.05),但两组患者术后7 d皮质醇、去甲肾上腺素、肾上腺素水平比较,差异均无统计学意义(P>0.05)。观察组患者首次下床时间为(1.41±0.34)d,明显短于对照组[(2.12±0.35)d],差异有统计学意义(P<0.05)。观察组术后3、6个月的HSS评分分别为(76.11±7.24)、(87.67±12.36)分,均明显高于对照组[(71.11±6.23)、(82.37±11.52)分],差异均有统计学意义(P<0.05)。结论老年膝关节置换术中应用床旁超声引导下连续隐神经阻滞联合全身麻醉效果显著,可降低患者术后疼痛程度,减轻患者应激反应,但与连续股神经阻滞比较可进一步改善患者定向力及股四头肌肌力,缩短术后卧床时间,辅助改善患者术后远期膝关节功能水平。

预应力混凝土连续刚构桥零号块混凝土水化热温度控制

针对某预应力混凝土连续刚构桥零号块浇筑时,由于工期原因无法采用分层浇筑方式而使用一次性浇筑方式所产生的水化热温控问题,提出在零号块的内部空心部分设置贴合内壁的大体积降温水箱为主的方法,以达到控制零号块混凝土水化热温度的目的。首先,采用MIDAS/FEA有限元软件对零号块进行水化热温度场及温度变化的数值模拟。然后,根据模拟结果设计零号块温度测量系统,实时观测零号块混凝土的温度变化。通过对比各个测点温度的计算值和实测值,发现新的温控方法能够有效地将温升峰值控制在76℃以内,最大里表温差控制在20℃以内。

鸡尾酒疗法联合连续股神经阻滞在膝关节周围恶性骨肿瘤患者术后镇痛中的应用效果

目的:观察鸡尾酒疗法联合连续股神经阻滞(FNB)在膝关节周围恶性骨肿瘤患者术后镇痛中的应用效果。方法:选取2020年9月至2022年9月于该院行全膝关节置换术(TKA)的107例膝关节周围恶性骨肿瘤患者进行前瞻性研究,采用随机数字表法将其分为对照组53例和观察组54例。对照组术后给予FNB镇痛,观察组在对照组基础上联合鸡尾酒疗法镇痛,比较两组术后疼痛程度[被动活动视觉模拟评分表(PVAS)、静息状态视觉模拟评分表(RVAS)]评分、下肢微循环指标[足背动脉血流量、踝肱指数(ABI)]水平和血清炎性因子[肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、C反应蛋白(CRP)]水平。结果:观察组术后24、48 h的RVAS、PVAS评分均低于对照组,差异有统计学意义(P<0.05);术后48 h,两组足背动脉血流量、ABI均低于术前,但观察组高于对照组,差异有统计学意义(P<0.05);术后48 h,两组TNF-α、IL-6、CRP水平均高于术前,但观察组低于对照组,差异有统计学意义(P<0.05)。结论:鸡尾酒疗法联合FNB应用于膝关节周围恶性骨肿瘤患者术后镇痛可提高下肢微循环指标水平,降低RVAS评分、PVAS评分和血清炎性因子水平,效果优于单纯FNB镇痛。

2023年河南麦收连阴雨的形成和环流异常分析

2023年5月25—30日河南遭遇了1961年以来同期持续时间最长、影响最大的连阴雨天气过程。连阴雨天气导致小麦大幅减产,品质下降,豫南、豫中和豫东部分种子田失去种用价值,被评为“烂场雨”。利用常规观测资料、NCEP再分析资料和EC数值预报产品,对这次连阴雨过程的大尺度环流形势和影响系统进行分析。结果表明:(1)该天气过程发生在异常大气环流背景下,西太平洋副热带高压显著偏强,脊线5天滑动平均位置偏北达8个纬度,越过25°N线;西伯利亚高压也显著偏强且频繁向南暴发。(2)乌拉尔山阻塞系统的形成导致我国新疆西北部长时间维持一深厚冷涡,从而在35°—40°N形成了稳定纬向环流,冷涡底部不断有冷空气分裂东移南下影响河南。远距离超强台风的逼近导致副热带高压迅速西伸北抬,在其外围形成了一条宽广、深厚的从南海伸向中纬度地区的暖湿气流输送带,最终在豫西北汇聚出低空急流。随着暖湿气流输送带向北扩展,在大风速区的前方,对流层中低部有明显的空气质量和水汽的辐合,从而引发上升运动的发生发展,导致多地暴雨、局部大暴雨的出现。(3)南北两个异常的天气系统的结合,促成了中纬度能量锋区的稳定维持,锋面抬升对暖区降水起到增幅和维持作用。(4)数值模式对中、短期环流趋势和影响系统均作出了较准确的预报,但对降水量级及其分布的预测还需要进一步推敲订正。

高比例电力电子电力系统过电压(三):直流故障下新能源暂时工频过电压机理

在高比例新能源和大容量直流输电工程大量投运的背景下,电力系统过电压问题日渐凸显,不仅制约直流输电能力,而且可能引发新能源大规模脱网。在新能源占比较高时,与交流设备相比,新能源的工频过电压耐受能力更低,该文针对直流故障引发的送端新能源机端过电压问题进行机理分析。首先,建立直流闭锁和直流多次换相失败后闭锁故障状态下新能源及传统同步机经特高压直流外送系统的等效电路分析模型,基于矢量关系,解析推导直流故障下的暂时工频过电压最大值。然后,分析直流输电功率水平、新能源并网功率、新能源低电压穿越控制参数、同步机至直流换流站电气距离以及新能源至直流换流站电气距离等因素对新能源机端电压最大值的影响。最后,通过PSD-BPA仿真软件在小算例系统和我国西北等值电网中验证理论分析的有效性。