Positive And Negative Sequence Current Measurements Menu - DEMA CPM 310 G User Manual

Positive & Negative Sequence (P/N) Current Measurements
Menu
Main Screen » Menu »
Measurements » P/N Sequence
Current
I gets the same value with the phases when the phase current values get the same value; while
1
having the average value of the phases' when load imbalance takes place.
I2 (Negative Sequence Measurement)
Negative sequence component of the phase current values is formulated as follows.
��
���� = �� + �� �� + ����
�� �� �� ��
Where,
I : represents the negative sequence current vector.
2
I gets zero value when the phase current values the same value; while having values greater than 0
2
when load imbalance takes place.
I2/I1 (Negative Sequence / Positive Sequence)
I / I (Negative Sequence / Positive Sequence) value is monitored on this row. The momentary value
2 1
is displayed in percentages. □
Positive and Negative Sequence Current Measurements
Menu
screen is shown on the left picture.
The menu monitors the following measurements.
I1 (Positive Sequence Measurement)
Positive sequence component of the phase current
values is formulated as follows.
× ������ [ ���� − �� ]
�� (��) = ��
�� ��
�� (��) = �� × ������ [ ���� − ( �� + ������° )]
�� ��
× ������ [ ���� − ( �� + ������° )]
�� (��) = ��
�� ��
��
���� = �� + ���� + �� ��
�� �� �� ��
Where,
I (t) the momentary values of phases' current,
r,s,t
I current peak value,
p
I positive sequence current vector,
1
I , I ve I phase current vectors,
r s t
a an operator that rotates a vector by 120°,
a 2 an operator that rotates a vector by 240°.
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