Energy Meter Show Different Current on Different Phase

The problem lies in the lack of vision and knowledge of single-phase electrical installers.

When adding single phase loads to an existing three-phase LV board, the electrician naturally starts from the top-left, which in most boards is the red phase. So the red phase is usually more heavily loaded than others, which is reflected in the high current in the red phase of the HV incomer.

Fortunately, the remedy is simple: slap the electrician round the head with a wet kipper until the excess of red single phase loads are redistributed more evenly across the three phases.

sir you cannot understand the question the energy meter is installed on 66 KV level in the grid station and the power is supply on the 66 KV level

So? Why is that relevant? All the single phase loads are on the LV side.

Perhaps the wet kipper should be applied to the OP and not the electrician?

OK my story runs on the LV side.

Two TV Transmitters were to be approved by customer and we were running the final tests. The last test for the approval report was the current draw on the three phase mains input of both identical transmitters. Transmitter A had on all three phases 200A each - as it was expected and verified several times before.

At transmitter B due to mechanical reasons we started to take measurements in reverse T= 200A S=200A but R phase showed something funny: 200A but jumped for 1 sec to 210A and then for 2 seconds back to 200A. Even the customers engineer was scratching his head. This change could not be explained as other measurements during the whole day it was always 200A.

Closer inspection showed that there was an unaccounted for, new wire connected to this R terminal. Investigation resulted in the fact that someone from the station personal had unnoticed connected the red warning lights of the antenna tower to this terminal. Fog had come up so the warning lights turned on..... the rythm was 1sec ON 2 sec OFF. Took us quite some time to figure this out as the lights were hundreds of meters above our heads.

We had something similar on what were supposed to be known circuits. It turned out that the standby mode for a large copy machine included turning a heating circuit on and off in somewhat continuous patterns.

An extension cord and power strip under the raised floor was extended to a receptacle for the wrong panel.

Check to make sure your CTs are properly oriented.

Dear sehdev singh,

You have stated that you have installed 3 phase, 4 wire energy meter on 66kV level. At this voltage level, generally, it is either star or delta connected, 3 phase 3 wire system, there is no connection of neutral to the load. Therefore where you have connected neutral(4th.terminal) terminal of the energy meter?. In general, 3 phase 4 wire energy meter(unbalanced type meter) is connected in LV 3 phase 4 wire electrical power distribution system where loads are unbalance ,neutral is connected to loads and total unbalace current is flowing thro' the neutral line; the neutral of the energy meter is connected with neutral. The circuit diagram with CT connections is supplied with the meter.Therefore, it requested to check your meter connection.

Regards,

Manindra.

Can you check the accuracy class of CT mismatch