【判断题】
发电机准同期并列条件是指待并发电机和系统的电压、频率、相位接近相等，其偏差控制在一定的范围内
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相关试题
【判断题】
当系统发生事故电压严重降低时，应通过自动励磁控制装置（或继电强碱装置）快速降低发电机电压，如无法降低发电机电压，则应将发电机进行灭磁，并将发电机于系统解列
【判断题】
连锁切机即指在一回线路发生故障而切除这回线路的同时，连锁切除送电端发电厂的部分发电机
【判断题】
当变压器绕组发生少数线匝的匝间短路，差动保护仍能正确反应
【判断题】
当电流互感器10%误差超过时，可用两种同变比的互感器并接以减小电流互感器的负担
【判断题】
LFP-901B型微机保护装置，在启动元件动作160ms以后发生对称故障时、其阻抗继电器将无条件开放
【判断题】
输电线路采用串联电容补偿，可以增加输送功率、改善系统稳定及电压水平
【判断题】
为了使用户停电时间尽可能短，备用电源自动投入装置可以不带时限
【判断题】
在现场进行继电保护装置或继电器试验所需直流可以从保护屏上的端子上取得
【判断题】
发电机变压器组的过激磁保护应装在机端，当发电机与变压器的过激磁特性相近时，该保护的整定值应按额定电压较低的设备(发电机或变压器)的磁密来整定，这样对两者均有保护作用
【判断题】
发电机装设纵联差动保护，它是作为定子绕组及其引出线的相间短路保护
【判断题】
发电机的比率制动式纵差保护对发电机匝间短路无保护作用
【判断题】
220KV变压器保护动作后均应启动断路器失灵保护
【判断题】
为防止电流互感器二次绕组开路，在带电的电流互感器二次回路上工作前，用导线将其二次缠绕短路方可工作
【判断题】
在变压器高压侧引线单相接地故障时,单相短路电流导致变压器油热膨胀,从而使瓦斯保护动作跳闸
【判断题】
接到厂家通知及软件芯片后，各单位即可进行保护装置软件更
【判断题】
两组电压互感器的并联，必须先是一次侧先并联，然后才允许二次侧并联
【判断题】
在大接地电流系统中，在故障线路上的零序功率Ｓ是由母线流向线路
【判断题】
配有两套重合闸的220KV线路，正常时只投入一套重合闸，另一套重合闸切换把手可以放在任意位置
【判断题】
振荡时系统各点电压和电流值均作往复性摆动，而短路时电流、电压值是突变的
【判断题】
因为差动保护和瓦斯保护的动作原理不同,因而差动保护不能代替瓦斯保护.
【判断题】
我国电力系统中性点有三种接地方式，(1)中性点直接接地；(2)中性点经间隙接地；(3)中性点不接地
【判断题】
微机故障录波器启动后，为避免对运行人员造成干扰，不宜给出声光启动信号
【判断题】
微机继电保护装置在运行中要切换定值区时，应由继电保护人员按规定的方法改变定值，此时必须停用继电保护装置，但应立即打印（显示）出新定值，并与主管调度核对定值
【判断题】
任何电力设备和线路在运行中，必须在任何时候由两套完全独立的继电保护装置分别控制两台完全独立的断路器实现保护
【判断题】
一般来说，高低压电磁环网运行可以给变电站提供多路电源，提高对用户供电的可靠性，因此应尽可能采用这种运行方式
【判断题】
为了使不同中性点接地方式系统在发生接地故障时，电压互感器开口三角所得3U0均不大于100V，对于中性点接地系统（如110KV及以上），电压互感器变比选为UI（相）/UⅡ（相）/100伏，对于中性点不接地系统（如10.5KV），电压互感器变比选为UI（相）/UⅡ（相）/100/3伏
【判断题】
常规的变电站，只要有RTU远动设备即可以实现无人值班；变电站综合自动化不仅可以实现无人值班，而且大大提高了变电站的自动化水平
【判断题】
由于变压器在1.3倍额定电流时还能运行10秒，因此变压器过流保护的过电流定值按不大于1.3倍额定电流值整定，时间按不大于9秒整定
【判断题】
330KV系统正常运行的最高电压不能大于363KV，因此要装设过电压远跳装置来防止系统出现过电压
【判断题】
345KV±1.5%Un/110KV的有载调压变压器的调压抽头运行在+1.5%挡处，当110KV侧系统电压过低时，应将变压器调压抽头调至-1.5%挡处
【判断题】
接地故障时，零序电流和零序电压的相位关系与变电所和有关支路的零序阻抗角、故障点有无过渡电阻有关
【判断题】
电力系统继电保护的基本任务是当被保护元件发生故障时，能迅速准确地给距离该元件最近的断路器发出跳闸命令，使故障元件及时从电力系统中断开
【判断题】
二次回路标号一般采用数字或数字和文字的组合，表明了回路的性质和用途
【判断题】
电力系统中静止元件施以负序电压产生的负序电流与施以正序电压产生的正序电流是相同的，故静止元件的正、负序阻抗相同
【判断题】
电压互感器和电流互感器二次回路只能且必须是一点接地
【判断题】
熔断器的熔丝必须保证在二次电压回路内发生短路时，其熔断的时间小于保护装置的动作时间
【判断题】
发电机负序反时限保护是发电机转子负序烧伤的唯一主保护，所以该保护的电流动作值和时限与系统后备保护无关
【判断题】
发变组纵差保护中的差动电流速断保护，动作电流一般可取6～8倍额定电流，目的是避越空载合闸时误动
【判断题】
继电保护要求电流互感器在最大短路电流（包括非周期分量）下，其变比误差不大于10％
推荐试题
【简答题】
Napoleon took the gamble of pressing on to Moscow, 448 kilometers away. On September 7, 1812, the French and Russian armies met in fierce battle at Borodino, 112 kilometers west of Moscow. By nightfall, thirty thousand French and forty-four thousand Russians lay dead or wounded on the battlefield.
【简答题】
Again, the Russian army retreated to safety. Napoleon had a clear path to Moscow, but the occupation of the city became an empty victory. The Russians fled their capital. Soon after the French arrived, a raging fire destroyed two-thirds of the city. Napoleon offered a truce to Alexander I, but the Russian czar knew he could bide his time: "We shall let the Russian winter fight the war for us."
【简答题】
Napoleon soon realized he could not feed, clothe, and quarter his army in Moscow during the winter. In October 1812, he ordered his Grand Army to retreat from Moscow.
【简答题】
The French retreat turned into a nightmare. From fields and forests, the Russians launched hit-and-run attacks on the French. A short distance from Moscow, the temperature had already dropped to minus 4 degrees Celsius. On November 3, the winter's first snow came. Exhausted horses fell dead in their tracks. Cannon became stuck in the snow. Equipment had to be burned for fuel. Soldiers took ill and froze to death. The French soldiers dragged on, leaving the dead along every mile.
【简答题】
As the Russian army was gathering its strength, the French had to flee Russia to avoid certain defeat. At the Berezina River, the Russians nearly trapped the retreating French by burning the bridges over the swollen river. But Napoleon, by a stroke of luck, was able to build two new bridges. Thousands of French soldiers escaped, but at the cost of fifty thousand dead. Once across the Berezina, the tattered survivors limped toward Vilna.
【简答题】
Of the six hundred thousand soldiers Napoleon had led into Russia, less than one hundred thousand came back. The weakened French army continued its retreat westward across Europe. Soon, Britain, Austria, Russia, and Prussia formed a powerful alliance and attacked these stragglers. In March 1814, Paris was captured. Napoleon abdicated and went into exile, his empire at an end.
【简答题】
By early 1941, Adolf Hitler, leader of Nazi Germany, had seized control of most of Europe. To the east of Hitler's German empire was the Soviet Union. On June 22, 1941, without a declaration of war, Hitler began an invasion of the Soviet Union that was the largest military land campaign in history. Confident of a quick victory, Hitler expected the campaign to last no longer than three months. He planned to use the blitzkrieg, or "lightning war," tactics that had defeated the rest of Europe. The invasion had three broad thrusts: against Leningrad and Moscow and through the Ukraine.
【简答题】
Caught off guard by the invasion, Soviet leader Joseph Stalin instructed the Russian people to "scorch the earth" in front of the German invaders. Farms and factories were burned, destroyed, or rendered useless. During the first ten weeks of the invasion, the Germans pushed the front eastward, and the Russians suffered more than a million casualties.
【简答题】
In the north, the Germans closed in on Leningrad. Despite great suffering, however, the people of Leningrad refused to surrender. As the battle of Leningrad dragged on into winter, the city's situation became desperate. As food ran out, people died from hunger and disease. By the middle of the winter of 1941-1942, nearly four thousand people starved to death every day. Close to one million people died as a result of the siege.
【简答题】
In the center of Russia, Hitler's goal was the capture of Moscow. Because the Germans had anticipated a quick victory, they had made no plans for winter supplies. October arrived with heavy rains. "General Mud" slowed down the movement of the Germans' lightning attack.
【简答题】
As Hitler's armies drew closer and closer to Moscow, an early, severe winter settled over the Soviet Union, the harshest in years. Temperatures dropped to minus 48 degrees Celsius. Heavy snows fell. The German soldiers, completely unprepared for the Russian winter, froze in their light summer uniforms. The German tanks lay buried in the heavy snowbanks. The Russian winter brought the German offensive to a halt.
【简答题】
By the summer of 1942, Hitler had launched two new offensives. In the south, the Germans captured Sevastopol. Hitler then pushed east to Stalingrad, a great industrial city that stretched for 48 kilometers along the Volga River. Despite great suffering, Soviet defenders refused to give up Stalingrad.
【简答题】
In November 1942, the Russians launched a counterattack. With little or no shelter from the winter cold in and around Stalingrad, German troops were further weakened by a lack of food and supplies. Not until January 1943 did the Germans give up their siege. Of the three hundred thousand Germans attacking Stalingrad, only ninety thousand starving soldiers were left. The loss of the battle for Stalingrad finally turned the tide against Hitler. The German victories were over, thanks in part to the Russian winter.
【简答题】
During 1943 and 1944, the Soviet armies pushed the German front back toward the west. In the north, the Red Army broke the three-year siege of Leningrad with a surprise attack on January 15, 1944. Within two weeks, the heroic survivors of Leningrad saw their invaders depart. By March 1944, the Ukraine farming region was again in Soviet hands. On May 9, 1944, Sevastopol was liberated from the Germans. The Russians were now heading for Berlin.
【简答题】
For Hitler, the invasion of the Soviet Union had turned into a military disaster. For the Russian people, it brought unspeakable suffering. The total Soviet dead in World War II reached almost 23 million.
【简答题】
The elements of nature must be reckoned with in any military campaign. Napoleon and Hitler both underestimated the severity of the Russian winter. Snow, ice, and freezing temperatures took their toll on both invading armies. For the Russian people, the winter was an icy defender.
【单选题】
________不属于鼠类及体表寄生虫携带的病原体。___
A. 鼠疫耶尔森菌
B. 汉坦病毒
C. 黄病毒属病毒
D. 致病性钩端螺旋体
【单选题】
病媒生物死体样本运送，如果在24h内不能到达实验室的，运送过程中箱内温度应保持在_____。___
A. 4℃以下
B. 0℃以下
C. -20℃以下
D. 4℃以上
【单选题】
病媒生物死体样本运送，如果在装箱后4h内能够到达实验室的，运送过程中箱内温度应保持在______。___
A. 4℃以下
B. 0℃以下
C. -20℃以下
D. 4℃以上
【单选题】
病媒生物的死体样本运送，如果4h-24h内能到达实验室的，应将样品置于-30℃冷冻后再送样，运送过程中箱内温度应保持在________。___
A. 4℃以下
B. 0℃以下
C. -20℃以下
D. 4℃以上
【单选题】
恰加斯病也称为美洲锥虫病，其重要的传播媒介是________。___
A. 采采蝇
B. 厩螫蝇
C. 锥蝽
D. 埃及伊蚊
【单选题】
_______是黑热病内脏利什曼病的主要传播媒介。___
【单选题】
对于用作虫媒病毒分离或检测的蚊类标本，现场采集后应采用_______方式处置和运送。___
A. 杀虫剂熏杀+常温运输
B. 等蚊虫自然死亡+常温运输
C. 冷冻处死+常温运输
D. 冷冻处死+冷冻状态运输
【单选题】
_______不适用于入出境集装箱携带蝇、蚊、蠓的采集。___
A. 挥网法
B. 电动吸蚊器法
C. 直接捡取法
D. 二氧化碳诱蚊灯法
【单选题】
入境航空器应在______开始病媒生物监测。___
A. 卸货完成后
B. 抵达后
C. 等航空公司通知
D. 发现病媒生物时
【单选题】
进行集装箱携带输入性病媒生物监测时应准备的个人防护用品包括______。___
A. 乳胶手套、防护服
B. 防毒面具
C. 自给式呼吸器
D. 化学防护服
【单选题】
若要对采集到的输入性鼠类进行携带的病毒进行检测，取得其内脏器官的保存温度是_____。___
A. -80℃或以下
B. 0℃
C. 常温
D. 4℃-8℃
【单选题】
截获输入性活鼠或来自鼠疫流行区死鼠及经总署专家组确认和复核属于全国口岸首次截获的病媒生物应在______报告总署。___
A. 2小时之内
B. 8小时之内
C. 12小时之内
D. 24小时之内
【单选题】
入境船舶的蚊类和蝇类等双翅目病媒生物监测调查应白天在检疫锚地停泊期间进行，锚位距陆地距离不少于______，或在船舶靠泊后_____内进行。___
A. 1000 m；1h
B. 800 m、2 h
C. 400 m、4 h
D. 100 m、24 h
【单选题】
开展入境船舶输入性病媒生物监测工作中，在采集并保存病媒生物时由________陪同人员确认。___
A. 旅行社
B. 船方
C. 代理公司
D. 海事部门
【单选题】
在国境口岸或者交通工具上发现______有反常死亡或者死因不明的，国境口岸有关单位或者交通工具的负责人，必须立即向卫生检疫机关报告，迅速查明原因，实施卫生处理。___
【单选题】
采用鼠夹法监测鼠密度，应连续布放______。___
【单选题】
______不属于口岸区域鼠类常用监测方法。___
A. 鼠笼法
B. 鼠夹法
C. 目测法
D. 粉迹法
【单选题】
采用粉迹法监测鼠类密度时，滑石粉块的尺寸是______。___
A. 20cm×20cm
B. 30cm×30cm
C. 40cm×40cm
D. 50cm×50cm
【单选题】
______不属于蚊虫幼虫监测指标。___
A. 容器指数
B. 刺叮指数
C. 房屋指数
D. 布雷图指数
【单选题】
______不属于蚊虫成虫监测方法。___
A. 人帐诱法
B. 人工小时法
C. 小黑板法
D. 诱蚊器收集法
【单选题】
______不属于蝇类成虫监测方法。___
A. 诱蝇笼诱捕法
B. 捕蝇网网捕法
C. 直接目测法
D. 路径指数法
【单选题】
啮齿动物的臼齿常具有_____。___
【单选题】
______是仓鼠科特征。___
A. 背部有背囊
B. 尾部有尾囊
C. 口中两侧有颊囊
D. 腹部腹面有腹囊
【单选题】
_______蜱类假头基通常为矩形。___
A. 花蜱属
B. 璃眼蜱属
C. 扇头蜱属
D. 异扇头蜱属
