局部放电检测原理资料
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Review of Lecture 5
Contents:
1. Mechanisms of Dielectric Aging by PD 2. Process of Dielectric Aging by PD 3. The Influence Factors on Aging Rate 4. PD Evaluation Approaches
q 2 1 / 2 ( 2 d ) Cv
Ud (),Ud ( f )
Udm
fd 2
Rd
Cd
Ld
Rd
Cd
RC circuit
RLC circuit
9
2. The Detection Impedance
2.1 the RC circuit
A
u q /[C x
Ck C d ] C k Cd
udm
Ck
Ck u Ck Cd
q Cd (1
Ck q CC C x k d Ck Cd Ck Cd
高压电源，无局放
2. A sample cx affected by discharges.
放大器
7. An observation unit O
试品
3. An impedance Zd
观测单元
检测阻抗
7
1. The Basic Diagram of ERA
Zm Cx e Ck Zd
A o
Series circuit
u
Cx
Rd
u d
Cd )C x Ck Cv C d C x (1 C d C k )
Cd
udm
q Cv
Discharge extinguishes, Cd discharges via Rd dt ud (t ) udm e udm e t / d
B
d Ct Rd [Cd CxCk (Cx Ck )]Rd
1
Review of Lecture 5
Damage of internal discharge to polymer and oil-paper
branched type
brush type tree
2
Review of Lecture 5
The Influence Factors on Aging Rate
Definition of Electrical Aging :
Electrical aging is a type of dielectric deterioration under the long-term
electrical field and due to the fact of partial discharges.
qa(t)
qi
0.5
ui
0
t
ti
-0.5
0
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0.018
0.020
4
Lecture 6 Principles of Electrical Discharge Detection
局部放电检测的基本原理
5
Contents 1. The Basic Diagram of ERA
Estimation by the basic parameters (1) Apparent charge, qa (2) Discharge energy and power, W and P
(3) The phase angle of pulses
(4) Ui and Ue Estimation by the distribution (statistical) graphs
并联回路
8
2. The Detection Impedance
Functions: (1) to transfer the impulse current into voltage and 取得局部放电所产生的高频脉冲信号 (2) to suppress the interferences of power frequency and harmonic from source. 抑制试验电压的工频及其谐波的低频信号
d 1 /( Rd Ct )
Ct，Tuned capacitance调谐电容
Biblioteka Baidu
Damping constant 衰减常数
ud (t )
q d t e Cv
10
2. The Detection Impedance
ud (t )
ud (t )
q d t e Cv
FT
U d ( )
6
1. The Basic Diagram of ERA
Zm Cx Δu e Ck
i
o
4. A coupling capacitance Ck
耦合电容
5. A protecting impedance Zm
Zd
A
保护阻抗，低通滤波
6. An amplifier A
1. A high-voltage source e, free of discharge.
Electrical field stress Voltage frequency Situation of cavity and gas contents inside Temperature and humidity Mechanical force
HV
a
b
c
d
e
3
Review of Lecture 5
2. The Detection Impedance
脉冲电流法基本原理 检测阻抗 脉冲放大
3. The Amplification of Impulses 4. Detection Sensitivity 5. Impulse Resolution 6. Calibration
检测灵敏度
脉冲分辨率
放电量标定
Zm Ck e Cx Zd
Parallel circuit
o A
Two connecting methods (the location of Zd in circuit): 1. In series with the sample Cx- Series circuit.
串联回路
2. In series with the coupling capacitor Ck- Parallel circuit.
Contents:
1. Mechanisms of Dielectric Aging by PD 2. Process of Dielectric Aging by PD 3. The Influence Factors on Aging Rate 4. PD Evaluation Approaches
q 2 1 / 2 ( 2 d ) Cv
Ud (),Ud ( f )
Udm
fd 2
Rd
Cd
Ld
Rd
Cd
RC circuit
RLC circuit
9
2. The Detection Impedance
2.1 the RC circuit
A
u q /[C x
Ck C d ] C k Cd
udm
Ck
Ck u Ck Cd
q Cd (1
Ck q CC C x k d Ck Cd Ck Cd
高压电源，无局放
2. A sample cx affected by discharges.
放大器
7. An observation unit O
试品
3. An impedance Zd
观测单元
检测阻抗
7
1. The Basic Diagram of ERA
Zm Cx e Ck Zd
A o
Series circuit
u
Cx
Rd
u d
Cd )C x Ck Cv C d C x (1 C d C k )
Cd
udm
q Cv
Discharge extinguishes, Cd discharges via Rd dt ud (t ) udm e udm e t / d
B
d Ct Rd [Cd CxCk (Cx Ck )]Rd
1
Review of Lecture 5
Damage of internal discharge to polymer and oil-paper
branched type
brush type tree
2
Review of Lecture 5
The Influence Factors on Aging Rate
Definition of Electrical Aging :
Electrical aging is a type of dielectric deterioration under the long-term
electrical field and due to the fact of partial discharges.
qa(t)
qi
0.5
ui
0
t
ti
-0.5
0
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0.018
0.020
4
Lecture 6 Principles of Electrical Discharge Detection
局部放电检测的基本原理
5
Contents 1. The Basic Diagram of ERA
Estimation by the basic parameters (1) Apparent charge, qa (2) Discharge energy and power, W and P
(3) The phase angle of pulses
(4) Ui and Ue Estimation by the distribution (statistical) graphs
并联回路
8
2. The Detection Impedance
Functions: (1) to transfer the impulse current into voltage and 取得局部放电所产生的高频脉冲信号 (2) to suppress the interferences of power frequency and harmonic from source. 抑制试验电压的工频及其谐波的低频信号
d 1 /( Rd Ct )
Ct，Tuned capacitance调谐电容
Biblioteka Baidu
Damping constant 衰减常数
ud (t )
q d t e Cv
10
2. The Detection Impedance
ud (t )
ud (t )
q d t e Cv
FT
U d ( )
6
1. The Basic Diagram of ERA
Zm Cx Δu e Ck
i
o
4. A coupling capacitance Ck
耦合电容
5. A protecting impedance Zm
Zd
A
保护阻抗，低通滤波
6. An amplifier A
1. A high-voltage source e, free of discharge.
Electrical field stress Voltage frequency Situation of cavity and gas contents inside Temperature and humidity Mechanical force
HV
a
b
c
d
e
3
Review of Lecture 5
2. The Detection Impedance
脉冲电流法基本原理 检测阻抗 脉冲放大
3. The Amplification of Impulses 4. Detection Sensitivity 5. Impulse Resolution 6. Calibration
检测灵敏度
脉冲分辨率
放电量标定
Zm Ck e Cx Zd
Parallel circuit
o A
Two connecting methods (the location of Zd in circuit): 1. In series with the sample Cx- Series circuit.
串联回路
2. In series with the coupling capacitor Ck- Parallel circuit.