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With an unbalanced volatge system, the following will occurs:
1. Unbalanced Line currents causing overheating of cables.
2. Circulating currents.
3. Proper protection & operation of protecting devices like MCB, MCCB e.t.c.
4. It prevents underground cable faults. and so on....
An important property of a three-phase balanced system is that the phasor sum of the three line or phase voltages is zero, and the phasor sum of the three line or phase currents is zero. When the three load impedances are not equal to one another, the phasor sums and the neutral current (In) are not zero, and the load is, therefore, unbalanced. The imbalance occurs when an open or short circuit appears at the load.Any circuit that does not have all loads with the same impedance in all three branches is an unbalanced circuit. Typical causes: Unbalanced distribution of single phase loadsPhase-to-phase loadsUnbalanced3-phase loads Unequal impedance of cable runs or distribution lines Typical results: Current unbalance in3-phase induction motors can be several times the value of the voltage unbalance, leading to motor overheating and loss of efficiencyA major cause of premature motor failureA NEMA rated motor will exceed its nameplate capacity when phase voltageunbalance exceeds2%Damage to sensitive power electronic equipmentOverheating reduces insulation life, causing premature failure of the motorVFDs may be damaged or in some cases trip Neutral conductor current increases .
First of all, I don't know there is such three-phase120/240 volts electrical system.120/240 volts falls only on the single phase system. Anyhow, the importance of a balanced electrical system is somehow explained below.
it causes useless current to flow in3-phase devices such as transformers within the network and therefore increases the losses associated with this. Motors are especially affected by imbalance which causes them to overheat. Power factor correction capacitors too cannot be optimally switched in as they will over correct on unloaded phases while still not achieving suitable correction on the overloaded phase.
