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1、5.1 工频高电压试验 5.1 Working frequency high-voltage test,5.1.1 工频高电压的产生 5.1.1 Producing of working frequency high-voltage 5.1.2 工频高电压的测量 5.1.2 Measurement of working frequency high-voltage 5.1.3 绝缘的工频耐压试验 5.1.3 Insulative working frequency test of high-voltage,高压试验变压器是高压试验室最基本的、不可缺少的主要设备之一，它被当作电源，并且是交流、直
2、流和冲击电压试验设备的组成部分。 High-voltage test transformer, regarded as the electrical source, is one of the most rudimental equipment in High Voltage Technology Laboratory. Meanwhile, it is an integral part of the AC, DC and impulse voltage test equipment.,5.1.1 工频高电压的产生 5.1.1 Producing of working frequency hi
3、gh-voltage,高压试验室中的工频高电压通常采用高压试验变压器或其串级装置来产生，但对电容量较大的被试样，可采用串联谐振回路来获得工频高电压。 Working frequency high-voltage is usually produced by High-voltage test transformers or its cascade devices in High Voltage Technology Laboratory. However, the series resonant circuit is used for producing while the capacitan
4、ce of the sample is biggish.,高压试验变压器 High-voltage test transformer,高压试验变压器大多数为油浸式，有金属壳及绝缘壳两类。金属壳变压器又可分为单套管和双套管两种。 Most High-voltage test transformers, divided into two types of metal shell and the insulating shell, are oil-immersed type. Metal shell transformers can be divided into two kinds of sing
5、le casing and double casing.,单套管变压器的高压绕组一端接地，另一端（高压端）经高压套管引出。 The high-voltage winding of single casing transformer is grounded at one end and the other end, high-voltage end, fetches out through the high-voltage casing.,双套管变压器高压绕组的中点通常与外壳相连，这样每个套管所承受的只是额定电压Un的一半，因而可以减小套管的尺寸和重量。 The midpoint of the
6、double casing transformers high-voltage winding is usually connected with its shell. Thus each casing withstands only half of the rated voltage(Un). Therefore, the size and weight of the casing can be decreased.,当高压绕组一端接地时，外壳应当按0.5Un对地绝缘来。 While the high-voltage winding is grounded at one end, the s
7、hell should be insulated to the ground as 0.5 Un.,试验变压器一般作成单相的。高压绕组大多数做成多层绕组，层间绝缘由电缆纸和绝缘材料制成的圆筒组成。 Test transformer is usually made of single-phase. Most high-voltage windings are made of multi-layer windings. Layers of insulations are made up of cable paper and cylinders, made of insulation materia
8、ls.,额定工作电压大 High rated working voltage 容量较小 Smaller capacity 工作时间短 Short working time,试验变压器与电力变压器相比主要特点： Main characteristics of Test transformer in comparison with Power transformer,试验变压器的容量由被测试样在最不利的试验条件下(如淋雨时)需要的电流来确定。在特殊情况下，例如对于长电缆的试验，变压器必需的容量： The capability of the test transformer is determine
9、d by the current, the sample needs in the most unfavorable experimental conditions e.g. raining. In exceptional circumstances e.g. the tests for long cables, the capacitance that transformer required is as followed.,式中 U 试验电压，kV； C 试样电容， F； Ps 变压器容量，VA。 In the formula U Test voltage kV C Sample capa
10、citance uF Ps Capability of transformer VA,变压器绕组方式： Mode of transformers winding,图5-1 圆盘形绕组 Fig.5-1 Disc-shaped winding,（1）圆盘形绕组如图5-1所示，输出电压在几十千伏以下时，绕组由几个线圈串联组成。 Disc-shaped winding is shown in Fig.5-1.While the out-put voltage is not above decades of KV, the winding consists of several coils in ser
11、ies.,（2）圆筒形绕组结构如图5-2所示，低压绕组内侧靠近铁心，高压绕组同轴地套在低压绕组的外侧，内侧接地。 Cylindrical-shaped winding structure is as Fig.5-2. The interior of low-voltage wind is close to the iron core. Coaxial grounding cover is outside of the low-voltage winding, the output of high voltage.,图5-2 圆筒形绕组 Fig.5-2 Cylindrical winding,外
12、侧为高压输出，高压绕组的电压由内侧至外侧逐层升高，各层间采用与线圈同轴的绝缘筒进行绝缘，每层线圈的匝数也随电压的升高而减少，并且远离铁心部分。 Its grounding at the inside meanwhile. The voltage of high-voltage winding is increased layer by layer from the inner to the outer. Insulative canister, coaxial with the coil, is used between layers for insulation. The number of
13、 turns on each coil is also reduced with the increase of voltage. Meanwhile it is away from the iron core.,图5-2 圆筒形绕组 Fig.5-2 Cylindrical winding,2. 试验变压器串级装置 Cascade device of test transformer,由于受到体积重量的限制，单个试验变压器的额定电压不可能做得太高。但所需工频电压很高，往往采用串级线路把几台试验变压器串接起来。 As a result of the limitation of cubage an
14、d weight, high rating voltage of single test transformer is impossible. But the working frequency voltage required is usually awfully high. So cascade Lines are usually used to concatenate several test transformers.,数台试验变压器串级连接的办法就是将它们的高压绕组串联起来，使它们的高压侧电压叠加后得到很高的输出电压。 Specific measure is to connect t
15、heir high voltage windings in series. As a result their high side voltages after superposition obtain a high output voltage.,而每台变压器的绝缘性能要求和结构可大大简化，减轻绝缘难度，降低总价格。 Meanwhile the demand and structure of insulative capability of each transformer will be greatly simplified. Thus both the total costs and t
16、he degree of insulative difficulty will be reduced.,图5-3 由单高压套管变压器元件组成的串级变压器示意图 Fig.5-3 Transformer schematic cascades composed of single high-voltage transformer bushing,图中绕组1为低压绕组，2为高压组，3为供给下一级激磁用的串级激绕组。 In the Figure, winding 1 is low voltage wingding. Winding 2 is high voltage one. Winding 3 is cascade excitation winding which supplies the next level of exciting.,图5-3所示的串级方式称为自耦式串级变压器，这是目前最常用的串级方式。这里高一级的变压器的励磁电流由前面一级的变压器来供给。 The type of concatenation showed as F
