Table of Contents
How do you find the neutral current of an unbalanced load?
Note the neutral formula. If A, B and C are the three phase currents, the formula to find the neutral current is the square root of the following: (A^2 + B^2 + C^2 – AB – AC – BC).
What is the current in neutral conductor in 3phase unbalanced load in star connected system?
Since the load is unbalanced, the line currents will be different in magnitude and displaced from one another by unequal angles, The current in the neutral wire will be the phasor sum of the three line currents i.e. 1.
What happens if a system is unbalanced?
The unbalance Voltage always causes extra power loss in the system. The higher the voltage unbalance is the more power is dissipated means higher power bills.
How do you calculate unbalanced current?
How to calculate voltage unbalance
- Determine the voltage or current average.
- Calculate the largest voltage or current deviation.
- Divide the maximum deviation by the average voltage or current and multiply by 100 \% unbalance = (Max deviation from average V or I/average V or I) x 100.
What is the value of neutral current?
zero
In an ideal balanced sinusoidal three-phase power system, the neutral current is the vector sum of the three phase currents, should be equal to zero. Under normal operating condition, some phase unbalance occurs resulting in a small neutral current.
What will be the value of neutral current for three phase star connected balanced load?
Balanced inductive/resistive loads The sum of each of the voltages (and currents) at the star point is always zero. In a balanced system, the neutral current and neutral power is zero. You can think of a balanced three-phase system as three single-phase systems connected to a neutral line.
What causes current unbalance?
Current unbalance can be due to the motor or the supply line. If the high current and low current readings follow the same line leads, the supply is the cause of the problem. If the high and low readings follow the motor leads, the motor is the source of the problem.
Why there is current in neutral wire?
A neutral wire is used to complete the flow of electricity, it acts as a return path for the hot wire current. During normal operations, the neutral wire will carry current. We can see neutral in most of the electrical equipment, mostly in non-linear loads.
Why neutral current is high?
High neutral currents in buildings usually result from two situations. The first, and most common, is one where there are simply heavily unbalanced loads. This situation is usually easy to explain and remedy. The second situation involves current harmonic distortion.
What is the current at the neutral of a star-connected load?
If the load is star connected, with neutral as return path, this neutral will carry no current. This is so since vector sum of all three phase currents meeting at common neutral point is zero. Unbalanced load makes the lines / phases to carry different current magnitudes, and sum total of these at neutral point is not zero.
Why neutral current is zero in unbalanced condition?
The neutral current is always vector sum of individual phase currents. under balance load and no fault condition the neutral current would be zero. in the case of unbalanced case its not zero because the faulty phase would have more phase current in comparison to other phases.
Why is the neutral current zero in a delta connected system?
In a wye system, if the current load is equal on each of the three phases, AND the power factor is 1:1, the neutral current should be zero. But in a delta connected system, you can have equal loads on the three phases PLUS a load on the high leg that returns via the neutral.
What is the effect of unbalanced load on current?
Unbalanced load makes the lines / phases to carry different current magnitudes, and sum total of these at neutral point is not zero. Load in each phase is different, carrying its own current. Neutral in this case carries the net unbalanced current .