Require Help with Voltage Dip Problem in Distribution Line

What is the theoretical voltage drop for this length of cable and this load?

What steps have been taken to identify hot spots on the cable when the load is running, and what did these studies reveal?

for stop the voltage dropage u can instaal the servo stablizer

or call me for more help 9988064203

Voltage Drops in long line is very common. You have got all the operational datas of Electric power. As I understand, max. load operating is 50 Hp.

all YOU NEED IS ,

1. Install 25 KVAr capacitor in the inlet of Main Bus PDB

2. Install Wide range Voltage stabilizer. - may be 350V - 440 V range, with out put of 400V normal.

Thanks for Replay.

We have no observe any Hot Spot at Cable termination with Pole Insulator.

We have installed 2Nos of 50KVAR Manually Start Capacitor Bank at Main LT Panel..Right now one Capacitor Bank (50KVAR) is ON..

Voltage drop is Possible due to Long Line but Main Problem is Voltage goes down and not sustain Previous level i.e, without Load Voltage is 410 Voltage but When We give Load 50 HP.obviously it goes down for some second (due to Voltage DIP) but after some time it should have maintain near to 410 Volt but in my case it stuck at 390 to 385 Volt..

My problem is why Line does not maintain it's no load voltage in Load condition..

Is there any proxy effect may play it role because conductor is very close to each other.

We measure voltage between neutral and earth and it is 0.3 volt so no possibility of floating neutral

For the question 'why line doesn't maintain no-load voltage during load conditions' - it is possible provided there is no VAR drawal through the line.

Why don't you switchon both the capacitor banks at the time of starting the batching plant!!

One of the capacitor banks can be switched off if necessary after the plant stabilises.

You write there are voltage fluctuation problem also. Maybe the voltage measurements were not made at the one and the same time?

The cross section of the 2km long conductors may turn also insufficient.

When we measure Voltage at Trail end 385 To 390 Volt at the same Time At T/c Terminal Voltage is 443 V.

The conductor is clearly dropping voltage during the motor starting.

1.Try to switch over to soft starter if possible.The motor draws a starting current which will be reduced by softstarter.

2. Check the joints in the overhead cable and you will find some joints are weak.This will solve your problem

Following Observation is made at Trail end.

Voltage (R-Y) Voltage(Y-B) Voltage(B-R) R(Amp) Y(Amp) B(Amp)

443V 444V 445V 0Amp 0Amp 0Amp

389V 390V 387V 50Amp 52Amp 50Amp

400V 396V 398V 11Amp 10Amp 12Amp

For a LV line 2KM is very long. The problems with volt drop is only to be expected.

To be honest you need to look at your distribution system. Just on a cost basis the extra copper required must have far outweighed the cost of a MV line and switchgear.

What code name is Lynuc? Do you have a different description? If the cable is anything near to Penguin, with 2 circuits paralleled, you're going to get 22 volts drop at 32A + 65A (50hp motor) at 2 km. This is 5%, but for some reason you're getting 10%. Are you sure the motor is rated for 440v? Most I use are rated for 460V but can run on 440v, but not much less without consequences (Extra current draw and even less voltage on the line).

It is our observation that 1Amp Current will decrease 0.78Volt...i,e 50 Amp current will decrease 40Volt and this Voltage drop can not reach to its original Voltage.

I have calculate Voltage drop Calculation : For 50A load at trail end have 5% V.D but for 500A load at trail end have 34% V.D.

Right now at Trail end we have only 50Amp Load and it may be goes to 500 Amp in future So we are planning to installed Voltage stabilizer .

Need help to following Points:

(1) If we installed servo motor base Voltage stabilizer (300V to 415V)will Solve this Problem not for 50Amp Load but even in future load of 500A. ( 0.78 voltage drop for 1Amp so if we take 500Amp load in future may goes voltage down less than 300V so choise of Voltage stabilizer is best choise in this case)

(2) Only 11KV supply Voltage will solve this Problem at trail end (11KV Line at Trail end than Step Down from T/C of 11KV/415Volt and given to 500Amp Load)

=Our Assumption is that LT distribution at 415V ( for 1.6Km for 500Amp Load) may not give proper quality of power at trail end.

In any case, for 500 Amp line, Supply licensee gives you on 11kv supply only.

of course, for further LT distribution, even if your machines are sensitive to supply varuations more than 5%, you need stabilizer of suitable capacity.

You may install the stabilizer in main for 500 Amp, they are available in good quality.