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试述低压成套开关设备的绝缘配合原理与验证

来源:best365娱乐官方登录 电力设备有(you)限公司 发布(bu)时(shi)间:2022-01-15 13:24:29

摘(zhai)要(yao):绝(jue)(jue)缘(yuan)配合(he)问(wen)题(ti)是一个(ge)关(guan)系到(dao)电(dian)气(qi)设(she)备产(chan)(chan)(chan)品(pin)安全性(xing)的(de)重(zhong)要(yao)问(wen)题(ti),历(li)来(lai)受到(dao)来(lai)自各方面的(de)重(zhong)视(shi)。绝(jue)(jue)缘(yuan)配合(he)最早应用在(zai)高压(ya)电(dian)器产(chan)(chan)(chan)品(pin)中。我国的(de)电(dian)器产(chan)(chan)(chan)品(pin)中,由于绝(jue)(jue)缘(yuan)系统而引发的(de)事(shi)故(gu)占50%-60%,又由于在(zai)低压(ya)成套开关(guan)设(she)备和(he)控制设(she)备中正(zheng)式引用绝(jue)(jue)缘(yuan)配合(he)这个(ge)概念,只是近两年的(de)事(shi)情。所以(yi),正(zheng)确处(chu)理、解(jie)决好产(chan)(chan)(chan)品(pin)中绝(jue)(jue)缘(yuan)配合(he)问(wen)题(ti),是一个(ge)比较重(zhong)要(yao)的(de)问(wen)题(ti),应该给予足够的(de)重(zhong)视(shi)。

关(guan)键词:低压开(kai)关(guan)设备(bei) 绝缘(yuan)配合 绝缘(yuan)材料

0 引言

低(di)压(ya)(ya)成(cheng)套开(kai)关(guan)设(she)备(bei)(bei)(bei)在低(di)压(ya)(ya)供(gong)电(dian)(dian)系统中负责电(dian)(dian)能的控制(zhi)、保护、测量、转换和分配。由于低(di)压(ya)(ya)成(cheng)套开(kai)关(guan)设(she)备(bei)(bei)(bei)深入到生产现场、公共场所、居民住宅等地点,可以说凡是(shi)使用电(dian)(dian)气设(she)备(bei)(bei)(bei)的地方都应(ying)配备(bei)(bei)(bei)低(di)压(ya)(ya)设(she)备(bei)(bei)(bei),我国电(dian)(dian)能的80%左(zuo)右都是(shi)通过低(di)压(ya)(ya)成(cheng)套开(kai)关(guan)设(she)备(bei)(bei)(bei)供(gong)出,低(di)压(ya)(ya)成(cheng)套开(kai)关(guan)设(she)备(bei)(bei)(bei)的发展源(yuan)于材(cai)料工业、低(di)压(ya)(ya)电(dian)(dian)器、加工工艺(yi)和设(she)备(bei)(bei)(bei)、基础(chu)设(she)施建设(she)和人民的生活(huo)水平,所以低(di)压(ya)(ya)成(cheng)套开(kai)关(guan)设(she)备(bei)(bei)(bei)的水平从一个(ge)侧面反映(ying)了(le)一个(ge)国家的经济实力与科学技术、生活(huo)水平。

1 绝缘配合的基本原理

绝(jue)缘配(pei)合意指根(gen)据设(she)备的(de)(de)使(shi)用(yong)条件及周围(wei)环境(jing)来选择设(she)备的(de)(de)电气绝(jue)缘特性,只有在(zai)设(she)备的(de)(de)设(she)计基于其期望寿命中所(suo)承受的(de)(de)作用(yong)强度时,才能实现绝(jue)缘配(pei)合。绝(jue)缘配(pei)合的(de)(de)问(wen)题不仅来自设(she)备外部而且还来自设(she)备本身,是(shi)(shi)一(yi)个涉及各(ge)方面(mian)因素,须加以综合考虑(lv)的(de)(de)问(wen)题,其要点分(fen)为(wei)三(san)部分(fen):一(yi)是(shi)(shi)设(she)备的(de)(de)使(shi)用(yong)条件;二是(shi)(shi)设(she)备的(de)(de)使(shi)用(yong)环境(jing),三(san)是(shi)(shi)绝(jue)缘材料的(de)(de)选用(yong)。

1.1 设(she)备的(de)使(shi)用(yong)(yong)条件 设(she)备的(de)使(shi)用(yong)(yong)条件主要指设(she)备使(shi)用(yong)(yong)的(de)电压、电场、频率。

1.1.1 绝缘配合(he)与(yu)电(dian)(dian)压(ya)(ya)的关(guan)系(xi)。在(zai)考虑(lv)绝缘配合(he)与(yu)电(dian)(dian)压(ya)(ya)的关(guan)系(xi)中,要考虑(lv)在(zai)系(xi)统中可能出现(xian)的电(dian)(dian)压(ya)(ya)、设(she)备产(chan)生(sheng)的电(dian)(dian)压(ya)(ya),要求的持续电(dian)(dian)压(ya)(ya)运行等级(ji),以(yi)及人(ren)身(shen)安全、事故的危险性。

①电压(ya)与过电压(ya)的分类(lei),波形。

a持续工频电压,有(you)着恒(heng)定r、m、s的(de)电压;

b暂时(shi)过电压(ya),较(jiao)长持续时(shi)间的工频(pin)过电压(ya);

c瞬(shun)态(tai)过(guo)电压,几毫秒或(huo)(huo)更(geng)短的(de)持续时间的(de)过(guo)电压,通常(chang)是高(gao)阻(zu)尼的(de)振(zhen)荡或(huo)(huo)非振(zhen)荡的(de)。

——缓波(bo)前过电(dian)压:一种(zhong)瞬(shun)态过电(dian)压,通常是单(dan)方(fang)向的(de),到达(da)峰(feng)值的(de)时(shi)间(jian)(jian)为20μsTp5000μs之间(jian)(jian),波(bo)尾持续时(shi)间(jian)(jian)T2≤20ms。

——快波(bo)前过电压:一种(zhong)瞬态过电压,通常是单方向的,到(dao)达峰值时间为0.1μsT120μs,波(bo)尾(wei)持(chi)续时间T2≤300μs。

——陡波前过电(dian)压(ya):一种(zhong)瞬态过电(dian)压(ya),通常是(shi)单方向的(de),到达峰(feng)值的(de)时间为Tf≤0.1μs,总持(chi)续时间3ms,并(bing)带有叠加振(zhen)(zhen)荡,振(zhen)(zhen)荡频(pin)率地30kHzf100MHz之间。

d联(lian)合(he)(暂时、缓前(qian)(qian)波(bo)(bo)、快(kuai)波(bo)(bo)前(qian)(qian)、陡波(bo)(bo)前(qian)(qian))过电压。

根据上述的(de)过电(dian)压类型,可(ke)描述出标准的(de)电(dian)压波形。

②长期的(de)交流或(huo)直流电(dian)压与绝缘(yuan)配(pei)合的(de)关系,要(yao)考(kao)虑额定电(dian)压、额定绝缘(yuan)电(dian)压、实(shi)际(ji)工(gong)作电(dian)压。在系统正常、长期运行(xing)过程(cheng)中,主要(yao)要(yao)考(kao)虑额定的(de)绝缘(yuan)电(dian)压和(he)实(shi)际(ji)工(gong)作电(dian)压,而这一(yi)点(dian)除了要(yao)满足标准的(de)要(yao)求(qiu)外(wai),更(geng)要(yao)注意考(kao)虑我国(guo)电(dian)网的(de)实(shi)际(ji)情(qing)况。在目前我国(guo)电(dian)网质量尚(shang)不(bu)高的(de)情(qing)况下,设(she)计产品时,对绝缘(yuan)配(pei)合而言(yan),实(shi)际(ji)可能出现的(de)工(gong)作电(dian)压更(geng)重要(yao)。

③瞬态过(guo)(guo)电(dian)(dian)(dian)(dian)压(ya)(ya)与绝缘配合的(de)关系,这(zhei)与电(dian)(dian)(dian)(dian)气系统(tong)内(nei)被控过(guo)(guo)电(dian)(dian)(dian)(dian)压(ya)(ya)的(de)条(tiao)件有(you)关。在(zai)系统(tong)和设(she)备中(zhong)(zhong),存在(zai)多(duo)种形(xing)式的(de)过(guo)(guo)电(dian)(dian)(dian)(dian)压(ya)(ya),要全面考虑(lv)各种过(guo)(guo)电(dian)(dian)(dian)(dian)压(ya)(ya)的(de)影响,在(zai)低压(ya)(ya)电(dian)(dian)(dian)(dian)力系统(tong)中(zhong)(zhong),过(guo)(guo)电(dian)(dian)(dian)(dian)压(ya)(ya)可能会受到(dao)各种多(duo)变因素的(de)影响,所以,系统(tong)中(zhong)(zhong)的(de)过(guo)(guo)电(dian)(dian)(dian)(dian)压(ya)(ya)的(de)是通过(guo)(guo)统(tong)计的(de)方法来评定(ding)(ding),反映了一种发生概(gai)率(lv)(lv)的(de)概(gai)念,并(bing)可通过(guo)(guo)概(gai)率(lv)(lv)统(tong)计的(de)方法来决(jue)定(ding)(ding)是否(fou)需要保(bao)护控制。

1.1.2 设(she)(she)(she)备(bei)(bei)的(de)(de)(de)过电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)类(lei)(lei)别 根据设(she)(she)(she)备(bei)(bei)的(de)(de)(de)使(shi)用(yong)(yong)条件,要求的(de)(de)(de)长期持续电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)运行等(deng)级(ji)(ji)(ji),将(jiang)直接(jie)由(you)低压(ya)(ya)(ya)电(dian)(dian)(dian)(dian)(dian)(dian)网供电(dian)(dian)(dian)(dian)(dian)(dian)设(she)(she)(she)备(bei)(bei)的(de)(de)(de)过电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)类(lei)(lei)别分为Ⅳ级(ji)(ji)(ji)。过电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)类(lei)(lei)别Ⅳ级(ji)(ji)(ji)的(de)(de)(de)设(she)(she)(she)备(bei)(bei)是(shi)使(shi)用(yong)(yong)在(zai)配(pei)电(dian)(dian)(dian)(dian)(dian)(dian)装(zhuang)(zhuang)置(zhi)电(dian)(dian)(dian)(dian)(dian)(dian)源端的(de)(de)(de)设(she)(she)(she)备(bei)(bei),如电(dian)(dian)(dian)(dian)(dian)(dian)表和前级(ji)(ji)(ji)电(dian)(dian)(dian)(dian)(dian)(dian)流保护设(she)(she)(she)备(bei)(bei)。过电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)类(lei)(lei)别Ⅲ级(ji)(ji)(ji)的(de)(de)(de)设(she)(she)(she)备(bei)(bei)是(shi)安装(zhuang)(zhuang)在(zai)配(pei)电(dian)(dian)(dian)(dian)(dian)(dian)装(zhuang)(zhuang)置(zhi)中的(de)(de)(de)任务,以及设(she)(she)(she)备(bei)(bei)的(de)(de)(de)使(shi)用(yong)(yong)安全性(xing)和适用(yong)(yong)性(xing)必须符合(he)特殊要求者,如配(pei)电(dian)(dian)(dian)(dian)(dian)(dian)装(zhuang)(zhuang)置(zhi)中的(de)(de)(de)开(kai)关电(dian)(dian)(dian)(dian)(dian)(dian)器(qi)。过电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)类(lei)(lei)别Ⅱ级(ji)(ji)(ji)的(de)(de)(de)设(she)(she)(she)备(bei)(bei)是(shi)由(you)配(pei)电(dian)(dian)(dian)(dian)(dian)(dian)装(zhuang)(zhuang)置(zhi)供电(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)耗能设(she)(she)(she)备(bei)(bei),如家用(yong)(yong)和类(lei)(lei)似用(yong)(yong)途的(de)(de)(de)负载。过电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)类(lei)(lei)别Ⅰ级(ji)(ji)(ji)的(de)(de)(de)设(she)(she)(she)备(bei)(bei)是(shi)连接(jie)在(zai)将(jiang)瞬态过电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)限制在(zai)相当低水平的(de)(de)(de)设(she)(she)(she)备(bei)(bei),如具有(you)过压(ya)(ya)(ya)保护的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)子电(dian)(dian)(dian)(dian)(dian)(dian)路上。对(dui)于不直接(jie)由(you)低压(ya)(ya)(ya)电(dian)(dian)(dian)(dian)(dian)(dian)网供电(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)设(she)(she)(she)备(bei)(bei),必须考虑到系统设(she)(she)(she)备(bei)(bei)可能出现的(de)(de)(de)最高电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)及各(ge)种情况的(de)(de)(de)严重(zhong)组合(he)。

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电场(chang)(chang)情(qing)况分为均(jun)匀(yun)电场(chang)(chang)与非均(jun)匀(yun)电场(chang)(chang),在低(di)压成套开关设备中(zhong),一般认为是(shi)处(chu)在非均(jun)匀(yun)电场(chang)(chang)情(qing)况下(xia),关于频率问题,目前尚在考(kao)虑(lv)中(zhong),一般认为低(di)频对(dui)绝缘配合影响(xiang)(xiang)不大,但(dan)高频还(hai)是(shi)有影响(xiang)(xiang)的,尤(you)其是(shi)对(dui)绝缘材料。

1.2 绝(jue)缘配(pei)合(he)与环(huan)(huan)境(jing)条件的(de)(de)关系 设(she)(she)备所处(chu)的(de)(de)宏(hong)观(guan)(guan)(guan)(guan)(guan)环(huan)(huan)境(jing)影响(xiang)着(zhe)绝(jue)缘配(pei)合(he),从目前(qian)实际应用与标(biao)准(zhun)的(de)(de)要(yao)求(qiu)来看,气(qi)压(ya)的(de)(de)变(bian)化只考(kao)虑到海拔(ba)高度引起的(de)(de)气(qi)压(ya)的(de)(de)变(bian)化,日常的(de)(de)气(qi)压(ya)变(bian)化已经忽(hu)略,温度与湿度的(de)(de)因素也已忽(hu)略,但如果有更精(jing)确的(de)(de)要(yao)求(qiu)时,这些因素也还是应予以考(kao)虑。从微(wei)观(guan)(guan)(guan)(guan)(guan)环(huan)(huan)境(jing)上讲,宏(hong)观(guan)(guan)(guan)(guan)(guan)环(huan)(huan)境(jing)决定了微(wei)观(guan)(guan)(guan)(guan)(guan)环(huan)(huan)境(jing),但微(wei)观(guan)(guan)(guan)(guan)(guan)环(huan)(huan)境(jing)有可能(neng)(neng)会好于(yu)或坏于(yu)宏(hong)观(guan)(guan)(guan)(guan)(guan)环(huan)(huan)境(jing)设(she)(she)备,外壳不(bu)同的(de)(de)防护等级、加热、通风(feng)、灰尘都有可能(neng)(neng)影响(xiang)微(wei)观(guan)(guan)(guan)(guan)(guan)环(huan)(huan)境(jing),微(wei)观(guan)(guan)(guan)(guan)(guan)环(huan)(huan)境(jing)在相关标(biao)准(zhun)有明确规(gui)定,这就为(wei)产品的(de)(de)设(she)(she)计提供了依据。

1.3 绝(jue)缘(yuan)(yuan)(yuan)配合与绝(jue)缘(yuan)(yuan)(yuan)材(cai)(cai)(cai)料(liao)(liao) 绝(jue)缘(yuan)(yuan)(yuan)材(cai)(cai)(cai)料(liao)(liao)的(de)(de)问题相当(dang)复杂,它不(bu)同(tong)于(yu)(yu)(yu)气体,是一种(zhong)一旦遭到破坏(huai)便(bian)不(bu)可(ke)恢复的(de)(de)绝(jue)缘(yuan)(yuan)(yuan)介质,即使(shi)偶(ou)然发生的(de)(de)过电(dian)压事(shi)件(jian)也有可(ke)能造成永久(jiu)损坏(huai),绝(jue)缘(yuan)(yuan)(yuan)材(cai)(cai)(cai)料(liao)(liao)在(zai)长期的(de)(de)使(shi)用(yong)中,会(hui)遇到各(ge)种(zhong)各(ge)样情况,如放(fang)电(dian)事(shi)故等(deng)(deng),而绝(jue)缘(yuan)(yuan)(yuan)材(cai)(cai)(cai)料(liao)(liao)本身由(you)于(yu)(yu)(yu)长期积累的(de)(de)各(ge)种(zhong)因(yin)素,如热应(ying)(ying)力(li)(li)、温度,机(ji)械(xie)冲击等(deng)(deng)应(ying)(ying)力(li)(li),又会(hui)加速它的(de)(de)老化过程。对(dui)于(yu)(yu)(yu)绝(jue)缘(yuan)(yuan)(yuan)材(cai)(cai)(cai)料(liao)(liao)来讲,由(you)于(yu)(yu)(yu)品(pin)种(zhong)的(de)(de)多样性,其衡(heng)量绝(jue)缘(yuan)(yuan)(yuan)材(cai)(cai)(cai)料(liao)(liao)的(de)(de)特性指标虽多,但不(bu)统一。这(zhei)就为绝(jue)缘(yuan)(yuan)(yuan)材(cai)(cai)(cai)料(liao)(liao)的(de)(de)选择(ze)和使(shi)用(yong)带来一定难度,这(zhei)也就是目前从(cong)国(guo)际上对(dui)绝(jue)缘(yuan)(yuan)(yuan)材(cai)(cai)(cai)料(liao)(liao)的(de)(de)其它特性,如热应(ying)(ying)力(li)(li)、机(ji)械(xie)特性、局部放(fang)电(dian)等(deng)(deng)指标暂(zan)不(bu)予以考(kao)虑(lv)的(de)(de)原因(yin)。

2 绝缘配合的(de)验证(zheng)

目前(qian)验证绝(jue)缘配合的优选方法是(shi)使用冲击介电(dian)试验来进行,对于不(bu)同(tong)设备可选定不(bu)同(tong)额定冲击电(dian)压(ya)值。

2.1 用额(e)定冲击电压(ya)试验验证设备的(de)(de)绝缘配合 额(e)定冲击电压(ya)的(de)(de)为1.2/50μs的(de)(de)波形。

用此波(bo)形(xing)来(lai)模拟瞬态过(guo)(guo)电压(ya)、大气过(guo)(guo)电压(ya),同时也(ye)包(bao)括低压(ya)设(she)备(bei)(bei)的(de)(de)接(jie)通分断所产(chan)生(sheng)的(de)(de)过(guo)(guo)电压(ya),冲击试(shi)验(yan)电源脉冲波(bo)形(xing)发生(sheng)器其输出阻抗(kang)一(yi)般应(ying)大于500Ω,额定冲击电压(ya)值的(de)(de)确定,应(ying)根(gen)据设(she)备(bei)(bei)的(de)(de)使用场合,过(guo)(guo)电压(ya)类(lei)别和设(she)备(bei)(bei)的(de)(de)长(zhang)期使用电压(ya)来(lai)决定,并应(ying)根(gen)据相应(ying)的(de)(de)海(hai)拔高(gao)度(du)进行修正(zheng)。目(mu)前低压(ya)成套(tao)(tao)(tao)开关设(she)备(bei)(bei)对(dui)某些试(shi)验(yan)条件。如(ru)湿度(du)、温(wen)度(du)没有作出明确的(de)(de)规定,但也(ye)应(ying)该在(zai)成套(tao)(tao)(tao)开关设(she)备(bei)(bei)标准适用范围(wei)内,如(ru)设(she)备(bei)(bei)的(de)(de)使用环境超(chao)出了成套(tao)(tao)(tao)开关设(she)备(bei)(bei)的(de)(de)适用范围(wei),则必须(xu)予以考虑修正(zheng)。气压(ya)与温(wen)度(du)的(de)(de)修正(zheng)关系如(ru)下式:

K=P/101.3×293(ΔT+293)

K——气压与温度(du)的(de)修正(zheng)参数

ΔT——实(shi)际(ji)(试验室)温度(du)与(yu)T=20℃的(de)温差K

P——实际气(qi)压kPa

2.2 替代冲(chong)击(ji)电压(ya)(ya)的介(jie)电试(shi)(shi)验(yan) 对(dui)于低压(ya)(ya)成套(tao)开关(guan)设备可以用(yong)交流或(huo)直流试(shi)(shi)验(yan)来替代冲(chong)击(ji)电压(ya)(ya)试(shi)(shi)验(yan),但(dan)是(shi)这类试(shi)(shi)验(yan)方法比冲(chong)击(ji)电压(ya)(ya)试(shi)(shi)验(yan)要(yao)严酷(ku),应征(zheng)得制造厂的同意。

交流试验,在交流情况下,持(chi)续(xu)时(shi)间为3个(ge)周波(bo)。

直流试验,每相(正、负极)各施加电压三次,每次持续时间为10ms。

就目前我国(guo)的实际情(qing)况而言(yan),在(zai)高(gao)、低压(ya)电器(qi)产(chan)品(pin)中(zhong)(zhong)(zhong),设(she)(she)备(bei)的绝(jue)缘(yuan)(yuan)配(pei)合仍是一个较大的问(wen)题(ti)(ti),又由于(yu)在(zai)低压(ya)成套开(kai)关设(she)(she)备(bei)和控制设(she)(she)备(bei)中(zhong)(zhong)(zhong)正式(shi)引(yin)用绝(jue)缘(yuan)(yuan)配(pei)合这(zhei)个概(gai)念,只是近两年的事情(qing)。所以(yi),正确处理、解(jie)决好产(chan)品(pin)中(zhong)(zhong)(zhong)绝(jue)缘(yuan)(yuan)配(pei)合问(wen)题(ti)(ti),是一个比较重要的问(wen)题(ti)(ti)。

参考文献(xian):

[1]IEC439-1低压(ya)成套(tao)开关设备和(he)控制设备第(di)一部分:型(xing)(xing)式试验(yan)和(he)部分型(xing)(xing)式试验(yan)成套(tao)设备[S].

IEC890用外推法(fa)检查低压成套开关设(she)备(bei)和(he)控制设(she)备(bei)通过部分(fen)型式试验成套设(she)备(bei)的(de)温(wen)升[S].