高电压试验技术第二章

高电压试验技术High-Voltage

Testing

Technology第二章交流高电压的测量东liuxuand

高电压技术教研室Copyright@

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voltage

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of

Electrical

engineering,

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JiaoTong

University第二章交流高压的测量2.1

概述测量方法电力部门：电压互感器内：测量球隙静电电压表峰值电压表分压器整流充电电压旋转伏特计光电测量系统Copyright@

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of

Electrical

engineering,

Xi’an

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University测量系统分类测量系统：标准的测量系统：不确定度±1%以内reference

measuring

system具有足够的精确度和稳定性，认可气体系统认可的测量系统：不确定度±3%以内approved

measuring

system要求：初始性能测试历次性能校核和性能试验性能记录包含所有这些试验结果三种试验：验收试验性能试验性能校核Copyright@

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division,

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of

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engineering,

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JiaoTong

University2.2测量球隙一、测量原理气体放电：均匀场或稍不均匀场中间隙的放电电压与间隙距离成一定关系

Ud~d结构：一对直径相同的球，水平或垂直布置Copyright@

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engineering,

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UniversityCopyright@

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University二、测量回路GC0T测量回路R1R2R2：保护电阻

100k~1M

作用：限流阻尼高频振荡要求

保证间隙为稍不均匀场保证一定

距Copyright@

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voltage

division,

school

of

Electrical

engineering,

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JiaoTong

University三、测量方法1.直接测量：连续3次的平均值，偏差<3%大气条件修正：温度

气压标准大气条件：t0=20C，h0=11g/m3，p0=0.103MPa实际大气条件：t,h,p电压校正：V

k

Vs大气密度修正系数：

p

273

t0p0

273

t湿度修正系数：k

1

0.002(h

11)V:测量电压；Vs:标准大气下放电电压Copyright@

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of

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University2.作校正曲线高压侧电压值与试验变压器低压侧的仪表读数间的比例关系GR1R2T0C’试验回路校正曲线0U2/

VU1

/

kVCopyright@

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voltage

division,

school

of

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engineering,

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University四、优缺点优点：直接测量高电压（AC,DC,Impulse）结构简单，不易损坏有一定的准确度d<0.5D

不确定度±3%0.5D<d<0.75D

不确定度±5%缺点：需要放电引起过电压有分散性大气条件的影响UD周围环境的影响Copyright@

High

voltage

division,

school

of

Electrical

engineering,

Xi’an

JiaoTong

University2.3

静电电压表一、工作原理带正、负电荷的导体间存在着静电静电

~电荷量有关~导体间电位差有关lAF02F

r

Al

2F

0

r

A

U

2

U

l2Copyright@

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of

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engineering,

Xi’an

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UniversityF：一周期内的平均值U：交流电压的有效值二、类型与使用方法1.类型绝对仪非绝对仪Copyright@

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of

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engineering,

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University2.使用方法平衡

防振动 灰尘和风动Copyright@

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division,

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of

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engineering,

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University2.4

交流高压分压器原理：将高电压转换成低电压构成：高压臂和低压臂U2U1Z1Z2I2U1Z1A

U

1

I

2

Z1(Z1

Z2

)

U

2

U

1

Z2分压比k

(Z1

Z2

)

/

Z2Copyright@

High

voltage

division,

school

of

Electrical

engineering,

Xi’an

JiaoTong

University要求：不影响被测电压的幅值和波形，低压臂所测电压波形与原波形相同耗能小，分压比稳定，分压比与频率、幅值无关分压比与大气条件无关分压器应无电晕和绝缘泄漏电流分压器的试验：分压比的测定线性度的测定稳定性试验幅—频特性试验Copyright@

High

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of

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University一、电阻分压器电阻的选取U2U1R1R2分压比k

(R1

R2

)

/

R2材料：碳膜、金属膜电阻、线绕电阻阻值：流过电阻的电流为几十~上百mA用于100kV以下WHY?Copyright@

High

voltage

division,

school

of

Electrical

engineering,

Xi’an

JiaoTong

UniversityC’

△xK’/△x△xR’

△xU1lx对地杂散电容电压分布不均容性电流流过)

180

R(1幅值误差相角误差Z

R(1

jRC

)62

R2C

2Copyright@

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voltage

division,

school

of

Electrical

engineering,

Xi’an

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University二、电容分压器C2C1U1U2C1:集中式电容分布式电容标准电容器多个电容串联分压比：k

U1

C1

C2U

2C1Copyright@

High

voltage

division,

school

of

Electrical

engineering,

Xi’an

JiaoTong

UniversityU1lK'x'Cexxx分布式电容分压器的误差原因1）对地电容的影响I1I2对地杂散电容上流过对地电流I

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(1

1

Ce

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6

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有幅值误差，无相角误差Copyright@

High

voltage

division,

school

of

Electrical

engineering,

Xi’an

JiaoTong

University2)对高压部分的杂散电容对高压部分的杂散电容I1

I2I1

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1

U

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UC

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)''C1

C1

3

C1C2

C2

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CHk

(1I1I2HC'

xU12lK'xxx

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High

voltage

division,

school

of

Electrical

engineering,

Xi’an

JiaoTong

University3.

Ce与CH的综合作用U1lK'xeC'

xHC'

xxx16C'''11C

C

(1eC

2CH

)

2CH

)6C1C2

(1

Ce1

U

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1

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6C1C1C2

C2

Ce

2CHk

(1Ce=2CH无幅值误差Copyright@

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voltage

division,

school

of

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engineering,

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University三、低压回路VC2线C1C2RG1C2R

G：抑制可能的过电压R：

C2上的残余电荷Copyright@

High

voltage

division,

school

of

Electrical

engineering,

Xi’an

JiaoTong

University2.5

峰值电压表一、利用电容电流的整流utuc0iiGD1D2Ciu

UM

sintcostMdti

C

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High

voltage

division,

school

of

Electrical

engineering,

Xi’an

JiaoTong

University电容C：高压标准电容器利用测量球隙MUMUM

du

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f

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voltage

division,

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of

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engineering,

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University二、利用电容器上的整流充电电压MU

sintUMUM?C,V,D反向均不泄漏，A点电位长时间保持不变RCDVuAA一周内：C很短时间充电，较长时间放电t0TT1ucUMuCopyright@

High

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division,

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of

Electrical

engineering,

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UniversityRCtuC

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