Deansharafi
Electrical
- Dec 9, 2003
- 58
Hi all,
I am investigating power recordings on a site, which does not have considerable sources of producing harmonics. However I see that there are considerable harmonics on the red phase current only which seems strange to me.
There are small harmonics on voltage, which is normal and small harmonics on currents except for the Red phase.
How can this large harmonics be present on current, whereas the voltage of the same phase does not have these. Is it possible? This feature is almost the same throughout the plant. (The main electrical load in the plant are three phase 3.3KV motors).
Typical recordings look like below for the 3rd, 5th 7th harmonics:
Your thoughts please.
Time VA VB VC IA IB IC
10:25:08 3.7 5.9 3 7.1 2.8 2.8
10:25:18 5.2 5.9 3 7.1 1.4 2.8
10:25:28 4.5 6.7 2.2 5.7 1.4 4.3
10:25:38 3.7 6.7 3 5.7 1.4 2.8
10:25:48 4.5 5.9 2.2 5.7 1.4 1.4
10:25:58 5.2 6.7 2.2 4.3 2.8 1.4
10:26:08 4.5 6.7 2.2 19.9 1.4 2.8
10:26:18 5.2 5.9 2.2 9.9 1.4 1.4
10:26:28 5.2 5.9 4.5 5.7 2.8 2.8
10:26:38 3.7 6.7 1.5 11.3 2.8 1.4
10:26:49 4.5 5.9 1.5 28.4 1.4 2.8
10:26:59 3 5.9 1.5 12.8 2.8 1.4
10:27:09 4.5 5.9 3 5.7 1.4 1.4
10:27:19 4.5 5.2 2.2 5.7 0 1.4
10:27:29 4.5 5.9 3 8.5 2.8 2.8
10:27:39 4.5 5.9 2.2 14.2 1.4 1.4
10:27:49 4.5 5.9 3 7.1 2.8 1.4
10:27:59 3.7 5.9 2.2 7.1 2.8 2.8
10:28:09 3.7 6.7 2.2 5.7 2.8 2.8
10:28:19 3.7 6.7 2.2 5.7 1.4 2.8
10:28:29 4.5 5.9 2.2 7.1 1.4 1.4
10:28:39 3.7 5.9 3 7.1 2.8 2.8
10:28:49 3.7 5.2 2.2 27 2.8 2.8
10:28:59 3.7 5.9 3 7.1 1.4 1.4
10:29:09 3 5.9 3 7.1 2.8 1.4
10:29:19 3.7 6.7 2.2 5.7 1.4 2.8
10:29:29 3.7 5.2 2.2 18.4 1.4 2.8
10:29:39 3 5.9 3 5.7 2.8 1.4
10:29:49 4.5 5.2 2.2 5.7 1.4 2.8
10:29:59 3.7 5.9 2.2 7.1 1.4 1.4
10:30:08 3.7 5.2 3 9.9 1.4 1.4
10:30:18 4.5 5.2 3 5.7 2.8 2.8
10:30:28 3.7 4.5 3 5.7 1.4 1.4
10:30:38 3.7 5.2 3 5.7 1.4 1.4
10:30:48 3.7 5.2 3 4.3 2.8 2.8
10:30:58 4.5 5.2 3 5.7 2.8 1.4
10:31:08 4.5 5.9 3 14.2 1.4 1.4
I am investigating power recordings on a site, which does not have considerable sources of producing harmonics. However I see that there are considerable harmonics on the red phase current only which seems strange to me.
There are small harmonics on voltage, which is normal and small harmonics on currents except for the Red phase.
How can this large harmonics be present on current, whereas the voltage of the same phase does not have these. Is it possible? This feature is almost the same throughout the plant. (The main electrical load in the plant are three phase 3.3KV motors).
Typical recordings look like below for the 3rd, 5th 7th harmonics:
Your thoughts please.
Time VA VB VC IA IB IC
10:25:08 3.7 5.9 3 7.1 2.8 2.8
10:25:18 5.2 5.9 3 7.1 1.4 2.8
10:25:28 4.5 6.7 2.2 5.7 1.4 4.3
10:25:38 3.7 6.7 3 5.7 1.4 2.8
10:25:48 4.5 5.9 2.2 5.7 1.4 1.4
10:25:58 5.2 6.7 2.2 4.3 2.8 1.4
10:26:08 4.5 6.7 2.2 19.9 1.4 2.8
10:26:18 5.2 5.9 2.2 9.9 1.4 1.4
10:26:28 5.2 5.9 4.5 5.7 2.8 2.8
10:26:38 3.7 6.7 1.5 11.3 2.8 1.4
10:26:49 4.5 5.9 1.5 28.4 1.4 2.8
10:26:59 3 5.9 1.5 12.8 2.8 1.4
10:27:09 4.5 5.9 3 5.7 1.4 1.4
10:27:19 4.5 5.2 2.2 5.7 0 1.4
10:27:29 4.5 5.9 3 8.5 2.8 2.8
10:27:39 4.5 5.9 2.2 14.2 1.4 1.4
10:27:49 4.5 5.9 3 7.1 2.8 1.4
10:27:59 3.7 5.9 2.2 7.1 2.8 2.8
10:28:09 3.7 6.7 2.2 5.7 2.8 2.8
10:28:19 3.7 6.7 2.2 5.7 1.4 2.8
10:28:29 4.5 5.9 2.2 7.1 1.4 1.4
10:28:39 3.7 5.9 3 7.1 2.8 2.8
10:28:49 3.7 5.2 2.2 27 2.8 2.8
10:28:59 3.7 5.9 3 7.1 1.4 1.4
10:29:09 3 5.9 3 7.1 2.8 1.4
10:29:19 3.7 6.7 2.2 5.7 1.4 2.8
10:29:29 3.7 5.2 2.2 18.4 1.4 2.8
10:29:39 3 5.9 3 5.7 2.8 1.4
10:29:49 4.5 5.2 2.2 5.7 1.4 2.8
10:29:59 3.7 5.9 2.2 7.1 1.4 1.4
10:30:08 3.7 5.2 3 9.9 1.4 1.4
10:30:18 4.5 5.2 3 5.7 2.8 2.8
10:30:28 3.7 4.5 3 5.7 1.4 1.4
10:30:38 3.7 5.2 3 5.7 1.4 1.4
10:30:48 3.7 5.2 3 4.3 2.8 2.8
10:30:58 4.5 5.2 3 5.7 2.8 1.4
10:31:08 4.5 5.9 3 14.2 1.4 1.4