变压器励磁浪涌电流的保护热敏电阻,大功率电源软启动热敏电阻-华巨电子


变压器在通电瞬间会产生一个很大的电流尖峰叫浪涌电流,这种输入浪涌电流的出现原因是:当变压器电源在正弦输入电压的过零点起动时,变压器磁芯的磁化在前几个周期中被迫进入一种不平衡状态。结果,磁芯在每个半周饱和。而在此时,产生的励磁电流仅由较小的漏电感寄生电阻来抑制,这会产生很大的输入浪涌电流。

  浪涌电压/电流产生的原因

  1、变压器空载合闸瞬间会产生特别大的电流,叫励磁浪涌,检测励磁浪涌有两种方式:

  峰值励磁浪涌(Peak Inrush Current)和均方有效值浪涌(RMS Inrush Current)

  a)、峰值励磁浪涌(Peak Inrush Current):  指变压器在合闸瞬间产生的最大峰值电流;

  b)、均方有效值浪涌(Rms Inrush Current):指变压器在合闸过程中一个或几个(FLUK435测试仪标定为第一个浪涌波形25ms)的均方有效值;

  2、一般变压器励磁浪涌衰减很快,第五个波形就达到稳态,这样,峰值励磁浪涌和均方有效值浪涌差别很大,对供电系统设备的影响也不同,不同的供电网络设备考虑浪涌模式是不同的:

  a)、峰值励磁浪涌(Peak Inrush Current):  主要考虑供电网络电压畸变的考量依据

  b)、均方有效值浪涌(Rms Inrush Current):是变压器上游开关跳闸和上游熔丝和继电器选择的主要考量依据

  3、合闸浪涌的测试

  合闸浪涌测试最真实数据是在使用现场合闸,利用FLUK435捕捉浪涌(Peak或Rms)信号,有些变压器厂家提供的出厂合闸浪涌测试数据,和使用现场的测试数据差别非常大,造成用户合闸使用时,上游开关跳闸,系统电压畸变超标,这是因为设计变压器时没有考虑到实际现场的供电参数,而且没有考虑峰值励磁浪涌(Peak Inrush Current)的数据,以及均方有效值浪涌(Rms Inrush Current)和峰值励磁浪涌(Peak Inrush Current)两组数据之间的最佳比例。

  4、有些变压器生产厂家通过加装抑制或旁路励磁浪涌的回路方法来达到上游开关不至于因太高的合闸浪涌造成跳闸。但旁路励磁浪涌方法其合闸浪涌始终在系统存在,甚至造成上游第二级开关跳闸和系统电压畸变超标;抑制浪涌办法会造成系统电压骤升问题,另外增加的元器件造成系统操作复杂化,系统可靠性降低,国外已经不允许采用这两种方法。

  5、峰值励磁浪涌(Peak Inrush Current)和均方励磁浪涌有效值(RMS Inrush Current)的转换

  根据UL、IEC的研究以及国外ABB、MGE、APC、ETON、SOCOMEC、DCD等的研究结果,机房变压器的浪涌峰值电流在1.9-2.2倍的25ms均方浪涌有效值范围内为最佳。 

  由于电压突变引起的当变压器合闸时正是电源正弦波的波形进入零的位置时,变压器会产生很大的冲击电流,甚至会造成变压器保护动作跳闸。不过这种概率很低,所以平时变压器合闸时,其冲击电流都很小 变压器在空载合闸时会出现激磁涌流。其大小可达稳态激磁电流的80-100倍,或额定电流的6-8倍。涌流对变压器本身不会造成大的危害,但在某些情况下能造成电波动,如不采取相应措施,可能使变压器过电流或差动继电保护误动作。 变压器励磁涌流是变压器全电压充电时在其绕组中产生的暂态电流. 变压器投入前铁芯中的剩余磁通与变压器投入时工作电压产生的磁通方向相同时,其总磁通远远超过铁芯的饱和磁通量,因此产生较大的涌流,其中最大峰值可达到变压器额定电流的6-8倍.励磁涌流与变压器投入时系统电压的相角,变压器铁芯的剩余磁通和电源系统阻抗等因素有关.最大涌流出现在变压器投入时电压经过零点的瞬间(该时磁通为峰值).变压器涌流中含有直流分量和高次谐波分量,随时间衰减,其衰减时间取决于回路电阻和电抗,一般大容量变压器约5-10S,小容量变压器约为0.2S左右一般在工厂生产检验时在电源输入处串接设定电流的保护开关(如常用的 DZ47-63  C20)开机时不发生跳闸就说明激磁涌流小于该保护开关的额定电流当然要多开关几次测试实际的激磁涌流可以用用示波器,在输入电源串接一小无感电阻,用示波器监测开机瞬时的涌浪电流的峰值但变压器浪涌电流最大是在开机时刚好在电源正弦波的波形进入零的位置时。人工开机时间是随机的在最大值的机率很小要用专用罗氏线圈来测量,目前全球做的最好的是pearson这一家的,很贵,动辄几万,一般的不具备。

问题陈述与提出:

变压器引起浪涌电流,浪涌电流超过了影响变压器铁芯磁性的饱和电流。甚至变压器的二次启动时无负载时也会发生。浪涌电流的大小取决于在变压器打开时的瞬时AC 波。如果这个瞬间正好是AC 电压波正在经历它的峰值,那么将没有浪涌电流产生。如果这样的话,浪涌电流的量将保持正常无负载值。如果这个瞬间正好是AC 电压波经历它的零值时,那么引起的电流将非常高而超过饱和电流(见图一)。这种情况下,变压器就必须受到保护不受浪涌电流的损坏。

华巨电子变压器浪涌电流抑制保护方案:

此应用提供了一个方便的解决方案(图2)来处理变压器中浪涌电流超过饱和电流的问题。这个方案是用 NTC 热敏电阻与初级线圈串联。在开关打开时热敏电阻有个高阻值来抑制浪涌电流。短时间之后,NTC热敏电阻由于自热,阻值降低到一个很低的值而不影响正常工作。

华巨电子提供的大功率NTC热敏电阻能够满足这一要求,其最大电流可以达到32A的稳态电流,在220V中功率可达7KW的的变压器提供浪涌保护功能。


具体参数参阅华巨电子SCD系列大功率热敏电阻:http://www.sinochip.net/ntcremin/scd.htm

每个额定变压器:1000VA, 

每个变压器下降:30V

总额定变压器:2000VA

使用的滤波电容:30V,2300uF

 

使用的滤波电容:30V,2300uF

变压器保护指南-典型的浪涌电流限制器选择变压器

变压器单相输入电压连续电流浪涌电流阻抗X电感XLF能源最小R建议使用型号
千伏安VACAA(  Ω)(μH)( Hz)(J)(Ω)
0.51204.161041.6343286023.44.9SCD-10R06
12404.161043.2686426046.79.78SCD-10R08
22408.332081.6343286093.624.89SCD-10R15
324012.53121.09288160140.63.26SCD-4R720
548010.422602.66913602347.83SCD-10R15-480
1048020.835121.33457604693.922个SCD-2R025-480Vac串联或1个SCD-5R025-680ac

 

型号RSSI焦耳电压
MaxMaxMax
SCD-10R0610640240
SCD-10R0810890240
SCD-10R151015150240
SCD-4R7204.720300240
SCD-10R15-480Vac1015250480
SCD-2R025-480Vac225300480
SCD-5R025-680Vac525600680


华巨电子与AMETHERM互换对照表

Sinochip(华巨)AMETHERMRSSIJoules
PartPartMaxMax
SCD-0R230-30SL32 0R2300.230100
SCD-0R516-22SL22 0R5160.516160
SCD-0R530-30SL32 0R5300.530150
SCD-0R536-30KAS32 0R536-1000.536300
SCD-0R530-30KAS32 0R530-1000.530300
SCD-0R536-30SL32 0R5360.536150
SCD-0R536-30K1MS32 0R5360.536250
SCD-0R540-30K1MS32 0R5400.540250
SCD-0R550-35K1MS35 0R5500.550900
SCD-0R550-35KAS35 0R5500.550800
SCD-0R712-22SL22 0R7120.712120
SCD-1R010-15SL15 1R0101.01045
SCD-1R010-13SL12 1R0101.01028
SCD-1R020-20SL22 1R0201.02065
SCD-1R025-25/1.025120
SCD-1R030-30SL32 1R0301.030160
SCD-1R030-30KAS32 1R0301.030300
SCD-1R030-30KAS32 1R030-1001.030300
SCD-1R036-30SL32 1R0361.036160
SCD-1R036-30K1MS32 1R0361.036300
SCD-1R036-30KAS32 1R036-1001.036300
SCD-1R040-35K1MS35 1R0401.040800
SCD-1R040-35KAS35 1R0401.040800
SCD-1R308-13SL12 1R3081.3840
SCD-2R05-8SL10 2R0052.0530
SCD-2R018-25SL22 2R0182.01890
SCD-2R023-30SL32 2R0232.023250
SCD-2R025-30KSL32 2R0252.025300
SCD-2R025-30K1MS32 2R0252.025300
SCD-2R025-30KAS32 2R0252.025300
SCD-2R035-35K1MS35 2R0352.035750
SCD-2R035-35KAS35 2R0352.035700
SCD-2R53-8SL08 2R5032.5310
SCD-2R55-10SL10 2R5052.5530
SCD-2R55-12SL12 2R5052.5536
SCD-2R56-15SL15 2R5062.5640
SCD-2R58-13SL15 2R5072.5740
SCD-2R58-20SL22 2R5082.5890
SCD-2R58-20SL18 2R5082.5890
SCD-2R58-13SL15 2R5082.5840
SCD-2R59-15SL15 2R5092.5940
SCD-2R512-20SL22 2R5102.51090
SCD-2R515-20SL22 2R5152.51590
SCD-3R030-35K1MS35 3R0303.030750
SCD-3R030-35KAS35 3R0303.030600
SCD-4R03-05SL05 4R0034.035
SCD-4R03-08SL08 4R0034.0310
SCD-4R04-10SL10 4R0044.0420
SCD-4R08-15SL15 4R0084.0840
SCD-4R014-20SL22 4R0144.014100
SCD-4R023-30SL32 4R0234.023200
SCD-5R01-05SL05 5R0015.015
SCD-5R08-08SL08 5R0025.0210
SCD-5R03-10SL10 5R0035.0320
SCD-5R03-08SL08 5R0035.0310
SCD-5R04-13SL12 5R0045.0440
SCD-5R06-20SL22 5R0065.0650
SCD-5R06-20SL18 5R0065.0675
SCD-5R06-15SL15 5R0065.0650
SCD-5R012-20SL22 5R0125.012100
SCD-5R020-30SL32 5R0205.020200
SCD-5R020-30K1MS32 5R0205.020300
SCD-5R020-30KAS32 5R0205.020300
SCD-5R025-35KAS35 5R0255.025600
SCD-5R025-35K1MS35 5R0255.025600
SCD-7R02-09SL08 7R0027.028
SCD-7R05-15SL15 7R0057.0560
SCD-7R05-15SL15 7R0057.0560
SCD-7R07-15SL15 7R0077.0750
SCD-7R010-20SL22 7R0107.010100
SCD-7R015-30KMS32 7R0157.015250
SCD-8R03-13SL12 8R0038.0325
/SL03 1000110.012
SCD-10R02-11SL10 1000210.0210
SCD-10R02-9SL08 1000210.0210
SCD-10R03-11SL10 1000310.0317
SCD-10R04-13SL12 1000410.0440
SCD-10R04-11SL10 1000410.0417
SCD-10R05-20SL22 1000510.0590
SCD-10R05-20SL18 1000510.0575
SCD-10R05-13SL12 1000510.0560
SCD-10R06-13SL12 1000610.0640
SCD-10R06-15SL15 1000610.0655
SCD-10R06-13SL12 10006-0310.0640
SCD-10R07-20SL22 1000710.0790
SCD-10R08-20SL22 1000810.0890
SCD-10R08-20K1MS22 1000810.08200
SCD-10R09-25SL22 1000910.09100
SCD-10R10-25/10.010105
SCD-10R15-30SL32 1001510.015150
SCD-10R15-30K1MS32 1001510.015250
SCD-10R15-30KAS32 1001510.015250
SCD-10R18-35K1MS35 1001810.018500
SCD-10R18-35KAS35 1001810.018500
SCD-14R05-20SL22 1400514.0575
SCD-14R07-20SL22 1400714.0775
SCD-15R04-15SL12 1500415.0440
SCD-15R12-30KMS32 1501215.012250
SCD-16R04-20SL22 1600416.04100
SCD-16R04-15SL15 1600416.0450
SCD-16R05-20SL22 1600516.051
SCD-17R04-13SL12 1700417.01730
SCD-20R02-09SL08 2000220.028
SCD-20R03-13SL12 2000320.0335
SCD-20R05-20SL22 2000520.05125
SCD-20R05-20K1MS22 2000520.05180
SCD-20R07-20KSL22 2000720.07125
SCD-20R08-30K1MS32 2000820.08250
SCD-20R09-30/20.09250
SCD-20R10-30K1MS32 2001020.010250
SCD-20R10-35K1MS35 2001020.010500
SCD-20R10-30KAS32 2001020.010250
SCD-20R10-35KAS35 2001025.010500
SCD-25R02-13SL12 2500225.0230
SCD-25R02-11SL10 2500225.0220
SCD-25R03-15SL15 2500325.0350
SCD-25R03-13SL12 2500325.0345
SCD-25R04-15SL15 2500425.0450
/SL05 3000130.013
SCD-30R04-15SL15 3000430.0440
SCD-30R04-15K1MS15 3000430.04135
SCD-30R05-20SL22 3000530.0580
SCD-30R05-20K1MS22 3000530.05150
SCD-30R06-20SL18 3000630.0665
SCD-33R01-09SL08 3300133.018
SCD-40R02-13SL12 4000240.0220
SCD-40R03-11SL10 4000240.0215
SCD-40R04-15SL15 4000440.0435
SCD-40R04-15K1MS15 4000440.04135
SCD-40R05-20SL22 4000540.0563
SCD-47R03-15SL15 4700347.0350
SCD-47R03-20SL18 4700347.0375
SCD-50R01-09SL08 5000150.0112
SCD-50R01-11SL10 5000150.0118
SCD-50R02-11SL10 5000250.0218
SCD-50R02-13SL12 5000250.0220
SCD-50R04-20SL22 5000450.0480
SCD-50R04-20K1MS22 5000450.04240
SCD-50R06-30K1MS32 50006-L50.06250
SCD-50R06-30K1AS32 5000650.06250
SCD-50R06-30K1MS32 5000650.06250
SCD-60R02-15SL15 6000260.0250
SCD-60R03-22SL22 6000360.0372
SCD-60R04-15SL15 6000460.0450
SCD-75R04-20K1MS22 7500475.04240
SCD-80R02-13SL12 8000280.0230
SCD-80R02-15SL15 8000280.0245
SCD-121R01-09SL08 12101120.0110
/SL05 12101120.0112
SCD-121R01-11SL10 12101120.0114
SCD-121R01-13SL12 12101120.0125
SCD-121R02-20SL22 12102120.0280
SCD-121R02-20K1MS22 12102120.02220
SCD-121R02-15SL15 12102120.0240
SCD-121R02-13SL12 12102120.0225
SCD-121R03-20SL22 12103120.0280
SCD-121R03-20K1MS22 12103120.03220
SCD-121R04-20K1MS22 12104120.04220
SCD-151R02-13K1MS12 15102150.02110
SCD-151R02-13SL12 15102150.0210
/SL03 22101220.012
SCD-221R01-13SL12 22101220.0130
SCD-221R02-20SL22 22102220.0272
SCD-221R02-15SL15 22102220.0240
SCD-221R3.5-20K1MS22 22103220.03.575


 华巨电子与RTI互换对照表

RTISinochip PartR@25℃D      MaxImaxRImax
Part Number华巨型号(Ohms)

(mm)

(AMPS)(Ohms)
SG260SCD-0R530-300.520300.01
SG326SCD-0R530-300.520300.01
SG100SCD-1R020-20115200.015
SG301SCD-1R020-20115200.015
SG405SCD-1R030-30125300.015
SG328SCD-1R030-30125300.015
SG416SCD-1R38-131.32580.05
SG110SCD-2R018-20215180.03
SG302SCD-2R018-20215180.03
SG420SCD-2R023-30225230.025
SG355SCD-2R023-30225230.025
SG120SCD-2R532.51530.15
SG303SCD-2R532.51530.15
SG130SCD-2R57-132.51570.05
SG304SCD-2R57-132.51570.05
SG140SCD-2R59-152.51590.04
SG305SCD-2R59-152.51590.04
SG150SCD-2R510-202.515100.04
SG306SCD-2R510-202.515100.04
SG160SCD-2R515-202.515150.03
SG307SCD-2R515-202.515150.03
SG170SCD-4R08-1541580.07
SG308SCD-4R08-1541580.07
SG32SCD-4R14-20420140.05
SG330SCD-4R14-20420140.05
SG190SCD-5R04-1151540.15
SG310SCD-5r04-1151540.15
SG200SCD-5R07-1351570.07
SG311SCD-5R07-1351570.07
SG44SCD-5R08-1552080.05
SG332SCD-5R08-1552080.05
SG26SCD-5R12-20515120.06
SG333SCD-5R12-20515120.06
SG210SCD-7R04-1371540.2
SG312SCD-7R04-1371540.2
SG64SCD-7R10-20715100.08
SG336SCD-7R10-20715100.08
SG337SCD-10R02-7101520.3
SG220SCD-10R03-9101530.2
SG313SCD-10R03-9101530.2
SG42SCD-10R05-11101550.2
SG338SCD-10R05-11101550.2
SG27SCD-10R06-13101560.15
SG314SCD-10R06-13101560.15
SG40SCD-10R08-20102080.1
SG320SCD-16R04-13162540.25
SG230SCD-20R1.75-1120151.750.6
SG315SCD-20R1.75-1120151.750.6
SG240SCD-40R02-13401520.6
SG316SCD-40R02-13401520.6
SG250SCD-121R03-151201530.9
SG317SCD-121R03-151201530.9

 

 华巨电子与EPCOS互换对照表

EPCOS PartSinochip PartR@25℃ImaxRImaxD Max
华巨型号(Ohms)(AMPS)(Ohms)

(mm)

B57464S0109M000SCD-1R20-25120

0.018

25
B57464S0209M000SCD-2R18-252180.02625
B57464S0509M000SCD-5R14-255140.04725
B57464S0100M000SCD-10R10-251010

0.084

25
B57364S0109M000SCD-1R016-20116

0.027

20
B57364S0209M000SCD-2R014-202.014

0.035

20
B57364S0259M000SCD-2R515-202.515

0.046

20
B57364S0409M000SCD-4R12-204.012

0.043

20
B57364S0509M000SCD-5R12-20512

0.047

20
B57364S0100M000SCD-10R8-20108

0.085

20
B57238S0259M000SCD-2R59.5-152.59.5

0.044

15
B57238S0309M000SCD-3R9-16-153.09.0

0.046

15
B57238S0479M000SCD-4R79-154.79.00.05515
B57238S0509M000SCD-5R9-155.09.00.05815
B57238S0709M000SCD-7R7-157.07.00.07815
B57238S0809M000SCD-8R7-158.07.00.08415
B57238S0100M000SCD-10R7-1510.07.00.09815
B57238S0150M000SCD-15R6-1515.06.00.12515
B57238S0160M000SCD-16R6-1516.06.00.12915
B57238S0200M000SCD-20R6-1520.06.00.13615
B57238S0250M000SCD-25R5-1525.05.00.18515
B57237S0109M000SCD-1R09-13190.03213
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