Fenlong Cultivation-the Fourth Set of Farming Methods Invented in China

The basic theory and effect of the new farming method of ＂Fenlong＂ cultivation which has been included in the main extension technology of Ministry of Agriculture of the People＇s Republic of China is fully illustrated for the first time, and it is the fourth set （generation） of farming modes and methods following manpower, animal and mechanical （tractor） farming. It follows the natural law to achieve soil activation, water saving, oxygen increase, warming and desalination through the active use of natural resources like soil, rainfall and solar energy, thereby promoting a new round of natural agricultural production and quality improvement and water con- servation, which has crop yield increase by 10%-30%, quality improvement of 5%, natural precipitation retaining increase by100%. The characteristics and mechanism are the use of spiral drill for one-time completion of the land preparation by drilling vertically to 30-50 cm of soil layer through high speed peeling. After instant high temperature and many fierce impacts, mechanical frictions, it could achieve the multiplication of the number of loose soil, soil physical modification and expansion of the soil nutrients, reservoirs, oxygen, microorganisms （＂Four pools＂）. Fenlong cultivation can give birth to new farming culture and civilization, and it can achieve the physical ＂desalinized＂ transformation and utilization of saline soil. The formation of Fenlong green farming technology system makes it possible to invent the farming tools of ＂serf-propelled Fenlong machinery＂ that has got the patent, and it is the method for farmland （dry land, paddy field） Fenlong cultivation, saline-alkali soil smash-ridging cultivation and for the abundance of grass ecology on degraded grassland. The application of Fenlong ＂4＋1＂ （arable, saline-alkali soil, grasslands, Sponge City＋rivers） green development in China can achieve the ＂double safety＂ of food and living space.

Effects of Different Farming Methods and Their Effects on Soil Physicochemical Properties of Guilin Maojian Tea Gardens

In order to further optimize the cultivation and agronomic technology of Guilin Maojian tea gardens, the effects, efficiencies and costs of different farming methods and their effects on the physiochemical properties of tea garden soil were studied through the modification of the test sites with the non-farming land as the control. The results showed that human farming, mini-tiller farming and crawler tractor farming could improve the physical and chemical properties of soil. After farming, the soil had good water retention but low moisture content compared to the control group, while the soil bulk density and hardness value were significantly lower than those of the control, and the porosity of soil was significantly higher than that of contrast. With the passage of time, soil bulk density and hardness value gradually increased after farming, while the porosity of soil decreased gradually. There were great differences in the effects, efficiencies and costs of different farming methods. Crawler tractor had the best and most stable farming effect, and the operation efficiency was 10 times that of human farming while the cost was only 0.39 times of human farming. Therefore, it was feasible to adopt mini-tiller or crawler tractor to carry out mechanical farming of Guilin Maojian tea garden, which provided theoretical references for the soil property improvement using mechanical farming and was favorable for promoting the popularization of farming machines and the acceleration of mechanization of tea gardens. But for tea plantations that are intended to be mechanized, apart from the mechanical and technical personnel to be configured in place, the site conditions, planting modes and mechanical way reservation of tea garden should be planned accordingly. It is recommended to select flat or gentle slope for reclamation, and preference is given to non-sexual tea tree varieties with big line spacing over 180 cm long. Moreover, the main road construction should be more than 3.0 m, and trunk road 2.0 m or above. And isolation ditch and drain should be set between the tea garden and the surrounding mountain forests and farmland.

Planning Method of Eco-environment Restoration Based on Enlarging Terrace and De-farming in Loess Hilly Region——A Case Study of Yangou Catchment

After expatiating the guiding ideology,contents,standards and principles of eco-environment restoration based on enlarging terrace and de-farming,this paper discussed the planning method and technical flow of enlarging terrace and garden plot in a small catchment of loess hilly region by means of GIS spatial analysis technology,and then the planning method was applied in Yangou catchment.The result showed that it is practicabl,and the areas of newly-built terrace and garden plot in Yangou catchment are at least 295.06 and 4.61 hm2,so that the areas of basic farmland and garden plot reach 359.23 and 622.69 hm2.After the land use structure is regulated,the forest coverage is 48.87%,and the permanent vegetation coverage is about 75% in Yangou catchment,while sediment reduction benefit is above 80% in slope land.In agricultural development,Yangou catchment can yield 1 645.13 tons of food supplies,above 9 340 tons of apples,and can feed 7 500 sheep every year.

Environmental Impacts of Farm Waste Treatment Methods and Perspectives of Valorization by Composting: The Case of the Farm “Sociétéde Provenderies du Cameroun (SPC)” of Foumbot

Waste recovery is an environmental, agronomic and economic asset. The farm “Société de Provenderies du Cameroun” (SPC) processes its wastes by incineration and landfill. During this study, environmental impacts of these two treatment methods were assessed in this farm and a composting experiment was also conducted. For the experiment, chicken carcasses and droppings mixed with wood shavings, straw, incineration ash, egg shells and cattle dung were distributed differently in four experimental composters C1, C2, C3 and C4 with the same starting weight. C1 consisted of the first three waste types, for C2, C3 and C4 a new waste was added in the order they are listed above. The results show that the major impacts associated with the incineration and landfilling of SPC waste are the degradation of the health of workers and surrounding populations, the occurrence of conflicts, and the pollution of the air, soil and groundwater of the site. As far as composting is concerned, the characteristics of three of the four composts obtained are usable as soil fertilisers. Indeed, at the end of the experiment, the pH of the four composters was basic (8), the temperature values were between 24°C and 34°C and the humidity values were between 37% and 41%. However, the last parameter, the C/N ratio, was not satisfactory for C1 (13.42), which eliminated it from mature and ready-to-use composts according to FAO standards. The C/N ratios of C2 (15.71), C3 (16.30), and C4 (18) composters were found to be good for mature and ready-to-use compost.

果园面源污染来源和迁移特征及影响因素研究进展

[目的]探明果园面源污染的来源、迁移特征及影响因素,为科学防控果园面源污染、改善土壤及水环境质量提供理论依据。[方法]基于国内外最新研究成果,分析果园氮磷、重金属、农药等污染物来源、迁移特征及影响因素,剖析现有研究不足,提出未来研究方向。[结果](1)果园肥料氮施用强度[565~1071.2 kg/(hm^(2)·a)]、氮磷流失系数总体高于农田,氮磷易在坡地果园坡底累积,在土壤中空间变异性高于农田和茶园。(2)在果园未被污水灌溉、周边无工业活动情况下,施用的肥料和农药及交通活动是果园土壤重金属的主要来源,重金属在土壤剖面迁移范围约在0.005~0.8 m。(3)果园苯并咪唑类、除虫菊酯类农药用量分别约为450~4 050 g/hm^(2),60~150 g/hm^(2),弱吸附性农药施用后受短期降雨影响大,中等吸附性农药受到降雨和蒸发双重影响,河流中农药含量呈现与降雨相关的季节性。(4)控制果园面源污染应优先处理初期径流,有效截留泥沙。林下生草可削减径流7.1%~98.7%,控制泥沙15.7%~99.8%,截留氮、磷分别为4.6%~98.5%和15.3%~96.6%,削减重金属18.8%~90.1%。(5)果园面源污染迁移特征与降雨时空分布一致,20%地表径流约输出50%以上污染负荷,极端降雨下果园径流系数、氮磷流失为普通降雨的2.6和11.5倍,降雨量、降雨强度是影响重金属和农药迁移的主要因素,在持续时间长,强度中等的降雨模式下,重金属和农药更容易下渗和往下游迁移。[结论]国内果园精细化管理尚在起步阶段,未来有待探明复杂因素影响下果园面源氮磷、重金属、农药等污染的迁移规律,精准识别面源污染影响时空范围与程度,科学阻控面源污染,在保障果品前提下有效减少面源污染流失,提升果园生态效益,降低环境风险。

Selection Wind Farm Sites Based on GIS Using a Boolean Method: Evaluation of the Case of Cameroon

The negative effects of traditional methods of electricity generation on the environment have created the need for strategic planning and development of renewable and sustainable energy systems. This paper presents the analysis of the suitability of wind farm sites using a Boolean decision-making approach based on geographic information system (GIS) modeling. This analysis is based on different climatic, geographical, economic and environmental criteria such as wind resource, slope, accessibility by road, proximity to the electricity network and optimal distance from airports. The results of the study show that the most favorable sites are mainly located in the northern part of the country, particularly in the Far North and North regions. There are also favorable sites in the North-West, South-West, West, Littoral and very little in the South while the central and eastern regions are not suitable. This is mainly due to the tropical forest that covers the entire region of East Cameroon and the low wind speed in these regions which is the determining factor for the installation of wind farms. The appropriate land for the installation of wind farms is approximately 2.56% corresponding to an area of 11,602.494414 km2. However, when we include the condition that a wind farm must have at least 4 km2 of surface area, is goes from 2.56% to 2.22% (11,602.494414 km2 to 10,344.424539 km2);thus a surface reduction of approximately 1258.069875 km2. We can conclude that despite the fact that Cameroon does not have a huge potential for wind energy because of the low wind speed observed in the country, it is still possible to have some favorable sites for the installation of the parks wind. In addition, a study of hybrid solar-wind systems could improve the efficiency of the power plants in Cameroon.

热带气旋对南方水稻产量影响的实证检验——基于广东水稻种植户的调研数据分析

【目的】量化因热带气旋导致的水稻产量损失,认识热带气旋灾害对农户生计和粮食安全的影响,为减少热带气旋灾害对水稻生产影响和提升热带气旋灾害的综合防范能力提供数据支撑与政策依据。【方法】运用2020—2022年广东省水稻种植户的混合截面数据,利用Tobit模型和2SLS模型,基于农户地块数据,从微观层次分析热带气旋导致水稻倒伏的影响和水稻倒伏对水稻产量的影响。【结果】热带气旋灾害在1%显著水平上导致水稻倒伏,即当热带气旋过境时水稻倒伏的可能性大大增加。从广东2020、2021、2022年连续3年农户调查数据来看,由热带气旋引起的倒伏率占全部倒伏率的22.9%;水稻倒伏率每增加10%,水稻产量大约下降2.9%。热带气旋对同一地区不同农户及不同地块上的水稻倒伏及产量的影响存在差异,对沿海地区水稻生产的影响要强于内陆地区。【结论】广东热带气旋灾害导致水稻倒伏,进而对水稻产量产生显著影响,危及粮食安全。为减少热带气旋灾害对广东水稻产量的负面影响,提出如下政策启示:进一步完善农田水利设施,加大高标准农田建设力度,确保因热带气旋导致的洪水能迅速排除;培育耐淹或抗倒伏的水稻品种,并在沿海地区进行推广;做好灾害性气候信息传达,加强热带气旋灾害预警系统建设;进一步完善粮食生产保险政策,提高赔付标准和赔付力度。

隔两年深松配合条旋耕显著提升冬小麦的氮素吸收利用效率和产量

【目的】探究耕作方式对小麦氮代谢和氮素利用效率的影响,为小麦高产高效生产提供理论依据。【方法】长期定位试验位于山东省济宁市兖州区小孟镇,始于2007年,供试冬小麦品种为‘济麦22’。设置常年翻耕(PT)、常年旋耕(RT)、常年条旋耕(ST)和隔两年深松+条旋耕(STS)4个处理。2023年在小麦开花期和成熟期采集植株样品,测定各器官含氮量。在开花后0~28天,每隔7天取一次样,测定旗叶硝酸还原酶(NR)、谷氨酰胺合成酶(GS)活性以及游离氨基酸和可溶性蛋白含量。于成熟期,调查产量及其构成因素,并计算氮素利用效率。【结果】与PT、RT和ST处理相比,STS处理提高了小麦旗叶硝酸还原酶活性、谷氨酰胺合成酶活性、游离氨基酸与可溶性蛋白含量,增加了开花期植株各部位和成熟期籽粒的氮素积累量、花前氮素转运量和转运率以及花后氮素吸收量对籽粒的贡献率,提高了氮素吸收效率、籽粒氮素利用效率、氮素收获指数和氮肥偏生产力。其中,成熟期籽粒氮素积累量增加了8.53%~30.15%,籽粒氮分配比例增加了4.59%~14.06%,千粒重和产量分别提高了4.20%~9.96%和7.83%~18.39%,氮肥偏生产力提高了7.85%~18.40%。【结论】隔两年深松+条旋耕(STS)的耕作方式可提高小麦氮代谢相关酶活性,增强氮素的吸收和同化能力,提高氮素利用效率,同时增加小麦籽粒产量。

海上风电场经柔直送出系统的虚拟导纳中频振荡抑制策略

随着柔性直流输电技术在远海风电的广泛应用,海上换流站接入远海风电场时出现了中频振荡现象,严重危害系统安全稳定运行。为此,提出了一种基于虚拟导纳的中频振荡抑制策略。首先,采用模块化状态空间法建立了海上风电场经柔直送出系统的小信号模型。然后,采用参与因子分析方法揭示了影响中频振荡的关键因素,并分析了各关键因素对中频振荡的影响特性。在此基础上,提出在柔直控制系统中添加虚拟导纳的阻尼控制策略,并基于阻尼控制器对中频、LCL振荡的差异影响划分了控制器参数的稳定域。最后,在Matlab/Simulink中搭建时域仿真模型。结果表明,所提策略在系统不同运行工况下均可有效抑制中频振荡,提高了系统稳定性。

农户务农人力资本禀赋对农地经营权抵押价值的溢价影响

在中国农地经营权抵押实践中,出于管控经营风险的考量,金融机构一般采用市场法而不是收益法评估被抵押农地经营权的价值,这种评估法往往忽视务农人力资本禀赋创造财富的价值作用,低估了农地经营权价值,从而潜在性诱致农户面临生产性融资约束。利用2022年中国西部4省原国务院、地方政府授权农地经营权抵押试点区1 539份实地调研数据,结合收益和市场两种评估法核算出的农地经营权抵押价值溢价差值,探究农户务农人力资本禀赋对农地经营权抵押价值的溢价影响。研究结果表明:在控制其他变量后,农户务农人力资本禀赋对农地经营权抵押价值溢价具有显著的正向影响。务农人力资本数量禀赋显著降低农地经营权抵押价值溢价影响概率和影响程度,而务农人力资本质量禀赋的影响则与之相反,经内生性和稳健性检验后,该结论依然成立。进一步研究发现,农户务农人力资本禀赋对农地经营权抵押价值溢价的正向影响在户主为青年、中年与农地经营规模大的家庭中更明显。因此,应当建立务农人力资本禀赋评价制度、创新“抵押+务农人力资本禀赋”评估方法,在农地经营权抵押实践中量化、变现并最终认可农户务农人力资本禀赋创造的经济价值。

黑土区坡耕地土壤侵蚀及水分利用效率对不同覆盖耕作模式的响应

为揭示不同覆盖耕作模式对黑土区坡耕地土壤侵蚀防治及水分利用效率的影响机制,设置顺坡免耕碎秆均匀覆盖(SM)、顺坡免耕覆盖作物(SC)、横坡免耕碎秆均匀覆盖(CM)和传统耕作(CK)4种覆盖耕作模式,研究分析黑土区坡耕地土壤水分动态变化规律,明确不同覆盖耕作模式的土壤侵蚀特征,分析不同覆盖耕作模式对水分利用效率的影响.结果表明:顺坡免耕碎秆均匀覆盖(SM)、顺坡免耕覆盖作物(SC)和横坡免耕碎秆均匀覆盖(CM)均能不同程度地增加土壤水分含量,防治土壤侵蚀和提高水分利用效率.SM处理、SC处理与CM处理较CK处理0~80 cm不同土层土壤含水率分别提高9.34%~18.20%,5.30%~11.54%和9.12%~19.84%;径流量、侵蚀量、降雨量和最大30 min雨强(I_(30))均与水分利用效率呈显著负相关性;SM处理、SC处理和CM处理的水分利用效率较CK处理均有提高,其增幅介于1.18%~10.76%.通过对比分析减流减蚀效果和水分利用效率,发现在防治土壤侵蚀,蓄水保墒及提高水分利用效率方面,横坡免耕碎秆均匀覆盖模式效果更好.

耕种模式对河西绿洲灌区玉米茎叶养分吸收及产量的影响

为探究河西绿洲干旱农业区不同耕种模式对玉米茎叶养分及产量的影响,分别将免耕(NT)、传统翻耕(CT)2种耕作方式与小麦玉米间作(W/M)、麦后插播冬油菜玉米轮作(W-G→M)、小麦玉米轮作(W→M)3种种植模式相结合,共设置6种模式处理,对不同模式下玉米茎叶的N、P、K、有机碳(OC)含量及产量进行比较分析。结果表明:在玉米生育期内,W/M模式下NT处理玉米叶中的N、P、K含量和茎中的N、K含量分别较CT处理高13.54%、26.66%、8.70%和8.00%、12.93%;W-G→M模式下,NT处理叶中的P、K含量和茎中的N、P、K、OC含量分别较CT处理高9.79%、14.72%和8.06%、14.13%、5.45%、0.44%;W→M模式下,NT处理叶中的P、K、OC含量和茎中的N、K、OC含量分别较CT处理高4.24%、3.82%、6.47%和13.21%、15.35%、0.05%。与轮作相比,W/M模式下茎中的N、K、OC含量分别较W-G→M高1.16%、9.09%、12.38%,较W→M模式则分别提高7.80%、3.66%、1.10%;W-G→M模式下叶中的N、P、OC含量和茎中的P含量分别较W→M模式高0.07%、5.76%、2.26%和5.72%。玉米成熟期,NT处理的玉米较CT处理平均增产8.72%,且W/M模式的土地当量比(LER)均大于1,NTW/M模式表现更好。综合分析,免耕有利于提高玉米茎叶中的养分含量,间作种植有利于作物增产增收,免耕小麦玉米间作模式可在河西灌区推广实践。

基于3DEEM-PARAFAC方法对不同秸秆还田方式下WSOC的组分与荧光特征分析

以三维荧光光谱结合平行因子法(3DEEM-PARAFAC)为主要分析方法,分析秸秆未还田条件下3种耕作方法(免耕、浅翻、深翻)及相应还田方法(秸秆免耕覆盖、浅翻还田、深翻还田)下,土壤水溶性有机碳(WSOC)的组分及不同土层的荧光特性。结果表明,土壤WSOC解析出4个荧光组分,分别为2个类腐殖质物质C1(310,240/410 nm)、C2(270/465 nm)和两个类蛋白物质C3(280,230/340 nm)、C4(220/300 nm);秸秆深翻还田在>35 cm土层有不同程度的促进类腐殖华物质C1、C2组分向类蛋白物质C4组分转化的趋势;土壤WSOC的来源均为植物源与微生物源的混合贡献,深翻还田在>35 cm土层腐殖化程度最低。秸秆还田与深翻对深层土壤WSOC中结构较为复杂、芳香性高的有机物的矿化分解有一定促进作用。

基于稀疏信息差值的集电线路故障精准定位方法

针对集电线路多分支网络结构故障定位过程时精度易受测点数量和行波波速影响的问题,提出一种基于稀疏信息差值的集电线路故障定位方法。按照集电线路划分故障区域。首先,通过变分模态分解从初始行波信号中提取第一本征模函数信号,并通过Stockwell变换将其进一步分解为S矩阵。然后,通过S矩阵计算其模矩阵Q,并计算所有模矩阵之间的能量相似性,建立区域决策矩阵来识别故障区域。最后,在确定的故障区域内设置虚拟故障点,根据故障区域首末端初始行波到达时间,计算测量行波和虚拟故障点之间的信息差异度,采用离散-连续粒子群实时修正故障分支和故障位置。仿真结果表明,该方法无需集电线路所有分支行波信息,大幅降低监测设备数量,消除波速影响,实现多分支集电线路的精准故障定位。

双馈风电场抑制次同步振荡的自适应增强阻尼控制方法

针对双馈风电场接入电网的次同步振荡问题,提出一种自适应增强阻尼控制策略。首先,基于无模型自适应理论设计一种双馈风电机组d、q轴阻尼联合控制方法,并给出控制参数优化方法。其次,将该无模型自适应阻尼控制方法与传统次同步阻尼控制方法相结合,得到一种自适应增强阻尼策略。最后,基于IEEE 39节点改造模型,验证该自适应增强阻尼控制策略的有效性和优越性。多机等值模型算例表明,该自适应增强阻尼控制策略对多机风电系统具有良好的适应性。该自适应增强阻尼控制策略可显著提升次同步振荡控制性能,对工况变化具有良好的适应性,可弥补传统次同步阻尼控制的不足,体现出较强的工程应用潜力。

蓖麻蚕的养殖及潜在毒素检测的研究进展

蓖麻蚕属于鳞翅目大蚕蛾科的一种昆虫,将蓖麻叶作为主要食物来源,以此实现自身各个阶段的生长发育。越来越多的地区和国家开始养殖蓖麻蚕。然而,蓖麻叶中含有多种有毒物质,蓖麻蚕是否对人体无害尚有待研究。简述了蓖麻蚕的养殖管理,对蓖麻蚕体内可能存在的蓖麻叶中的蓖麻碱、蓖麻毒蛋白、血细胞凝集素和变应原类毒素的检测方法进行简要概述,并对蓖麻蚕的有关食用方面进行了简单展望,以期为蓖麻蚕日后的食用安全性评估研究提供理论参考。

龙岩市部分规模化猪场猪粪便寄生虫检测与分析

目的:了解龙岩市5个区(市、县)的部分规模化猪场猪寄生虫感染情况,更好地保护猪群健康。方法:收集临床猪粪便样品,采用直接涂片法进行猪粪便寄生虫检测。结果:采集的229份粪便样品中,有101份检测出寄生虫,寄生虫感染率为44.11%(101/229),检测到3种猪寄生虫,分别为猪结肠小袋纤毛虫、猪球虫和猪蛔虫,其检出率分别为32.75%(75/229)、14.41%(33/229)和0.44%(1/229)。按采样季节分析寄生虫感染情况,发现春季的检出率为35.38%(23/65),夏季的检出率为51.06%(48/94),秋季的检出率为29.41%(5/17),冬季的检出率为47.17%(25/53)。结论:龙岩市部分规模化猪场存在寄生虫感染,且以土源性寄生虫感染为主,未发现生物源性寄生虫感染,本研究可为龙岩市猪寄生虫病防控提供参考依据。

基于旋转门算法的风速和风功率爬坡事件的识别方法及特征分析

风速的爬坡事件是风速在短时间内大幅度增加或减少,风电场功率同时发生大幅度改变,影响到电网安全运行,甚至引发电网局部频率降低、电压崩溃等事故。选取风电场内风机和气象铁塔的同期数据,通过旋转门算法(SDA)识别爬坡事件,分析爬坡事件的持续时间、爬坡幅度和变化速率,讨论山地地形对爬坡事件的影响。基于SDA设计了风速和功率的爬坡事件识别算法,算法参数取值为时间阈值4 h、风速阈值6 m·s^(-1)、功率阈值1000 kW,算法的识别效果较好,可有效识别爬坡事件。针对不同风机的爬坡事件识别,建议采用额定风速与切入风速差值的2/3数值作为风速阈值参数,采用额定功率的2/3数值作为功率阈值参数。山地地形对爬坡事件的影响较为显著,爬坡事件与风机处海拔高度、平均风速较为相关,不同地形下风机的爬坡事件的时间比例分布在6.5%~9.8%,平均值为7.8%。

基于生态足迹法的农业水土资源承载力分析——以三江平原友谊农场为例

本文以三江平原“黑土粮仓”——友谊农场为例,应用生态足迹法对当地的水土资源承载力进行定量评估。结果表明:(1)人均农业水资源生态足迹多年平均值为5.26 hm^(2)/人,生态承载力多年平均值为1.97 hm^(2)/人,水资源生态赤字,生态压力指数平均值为2.82,水资源利用处于不安全状态;人均耕地资源生态足迹小于生态承载力,耕地资源生态盈余,生态压力指数平均值为0.69,耕地资源利用处于安全状态;(2)友谊农场农业水土资源生态足迹和水土资源生态承载力的耦合协调度总体处于一般协调状态;(3)虽然农场土地资源丰富,但水资源稀缺,该地区的水土资源承载力协调水平还有很大的提升空间。研究结果对于黑土地保护,实现农业水土资源可持续发展有重要意义。

考虑风速波动性的海上风电渗透率极限评估方法

大规模具有间歇性、波动性且难以预测的风电接入电网后会给电网的电压和频率稳定性带来一系列挑战,因此如何评估已有区域电网的最大风电极限渗透功率成为了一个重要问题。现有研究大多分析了不同风电渗透率对电网电压和频率稳定性的影响,而缺乏对海上风电渗透率极限的评估。为此,考虑风速波动性的影响,提出了一种针对已有区域电网的海上风电渗透率极限评估方法。首先,通过研究海上风电场静态模型分析海上风电场功率输出特性;然后,通过构建含海上风电场和同步发电机的电网等效模型分析不同风电渗透率下并网点(Point of Common Coupling, PCC)电压与频率特性;最后,针对风速波动引起的电网电压和频率波动,提出考虑风速波动性的海上风电渗透率极限评估方法,并通过算例验证所提方法的有效性。随着海上风电渗透率增加,PCC电压降低速度和幅度也增大,加剧了有功波动对PCC电压的不利影响。此外,高渗透率条件下,电力系统可能面临有功功率缺额问题,造成频率偏差加剧。电压闪变和电压偏差在高渗透率时也随之增加,导致电能质量下降,频率合格率降低。