Circutor MYeBOX 150, Instruction Manual

Page: 47 / 94

47
Instruction Manual
MYeBOX 150 - MYeBOX 1500
Asymmetry coefficient, Ka:
ratio between the homopolar and direct components in an unbal-
anced system.
𝐾𝐾
𝑎𝑎
% =
|
𝑈𝑈
0
|
| 𝑈𝑈
𝑑𝑑
| 100
𝐾𝐾
𝑑𝑑
% =
| 𝑈𝑈
𝑖𝑖
|
| 𝑈𝑈
𝑑𝑑
| 100
𝐾𝐾
𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶
=
�
1 +
𝑒𝑒
1 + 𝑒𝑒 �
𝐼𝐼
1
𝐼𝐼
𝑒𝑒𝑒𝑒
�
2
� 𝑛𝑛 𝑞𝑞 �
𝐼𝐼
𝑛𝑛
𝐼𝐼
1
�
2
40
𝑛𝑛=2
𝐶𝐶𝐶𝐶 =
�𝑈𝑈
𝑝𝑝𝑖𝑖𝑝𝑝𝑝𝑝
�
| 𝑈𝑈
𝑅𝑅𝑅𝑅𝑅𝑅
| 100
Equation 1: Asymmetry coefficient.
Unbalance coefficient, Kd: ratio between the inverse and direct components in an unbal-
anced system
𝐾𝐾
𝑎𝑎
% =
|
𝑈𝑈
0
|
|
𝑈𝑈
𝑑𝑑
| 100
𝐾𝐾
𝑑𝑑
% =
|
𝑈𝑈
𝑖𝑖
|
|
𝑈𝑈
𝑑𝑑
| 100
𝐾𝐾
𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶
=
�
1 +
𝑒𝑒
1 + 𝑒𝑒 �
𝐼𝐼
1
𝐼𝐼
𝑒𝑒𝑒𝑒
�
2
� 𝑛𝑛
𝑞𝑞
�
𝐼𝐼
𝑛𝑛
𝐼𝐼
1
�
2
40
𝑛𝑛=2
𝐶𝐶𝐶𝐶 =
�𝑈𝑈
𝑝𝑝𝑖𝑖𝑝𝑝𝑝𝑝
�
| 𝑈𝑈
𝑅𝑅𝑅𝑅𝑅𝑅
| 100
Equation 2: Unbalance coefficient.

K-factor, Transformer power reduction factor :
The device calculates the K-factor according to IEEE C57�110 . The K-factor is a factor that is
used to calculate transformer power reduction.
𝐾𝐾𝐾𝐾 − 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 = � �
𝐼𝐼𝐼𝐼
ℎ
𝐼𝐼𝐼𝐼
𝑅𝑅𝑅𝑅
�
2
ℎ
2
∞
ℎ =1
=
1
𝐼𝐼𝐼𝐼
𝑅𝑅𝑅𝑅
2
� 𝐼𝐼𝐼𝐼
ℎ
2
∞
ℎ=1
ℎ
2
Equation 3: K-factor �
Where:
I
R
, denotes nominal rms load current of the transformer,
h , denotes harmonic order.

Crest Factor
The crest factor is the ratio between the peak value and the RMS value of a voltage or a peri-
odic current. The purpose of the crest factor is to give an idea of the wave peak and it is used
primarily for current waves.
𝐾𝐾
𝑎𝑎
% =
|
𝑈𝑈
0
|
| 𝑈𝑈
𝑑𝑑
| 100
𝐾𝐾
𝑑𝑑
% =
| 𝑈𝑈
𝑖𝑖
|
| 𝑈𝑈
𝑑𝑑
| 100
𝐾𝐾
𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶
=
�
1 +
𝑒𝑒
1 + 𝑒𝑒 �
𝐼𝐼
1
𝐼𝐼
𝑒𝑒𝑒𝑒
�
2
� 𝑛𝑛
𝑞𝑞
�
𝐼𝐼
𝑛𝑛
𝐼𝐼
1
�
2
40
𝑛𝑛=2
𝐶𝐶𝐶𝐶 =
�𝑈𝑈
𝑝𝑝𝑖𝑖𝑝𝑝𝑝𝑝
�
| 𝑈𝑈
𝑅𝑅𝑅𝑅𝑅𝑅
| 100
Equation 4: Crest Factor
In a perfect sinusoidal wave, the peak is √2 times greater than the RMS value; therefore the
crest factor is 1�41 . For waves with very high peaks, the crest factor will be over 1�41