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The receiving end voltage of a transmission line will be greater than sending end voltage if the load is
Greater than surge impedance loading
Less than surge impedance loading
Equal to surge impedance loading
Insufficient data
Less than surge impedance loading
The receiving end voltage becomes greater than the sending end voltage at light loads, a phenomenon known as the Ferranti effect. This occurs because the capacitive shunt current of the transmission line exceeds the load current, causing a voltage rise at the receiving end.
The receiving end voltage becomes greater than the sending end voltage at light loads, a phenomenon known as the Ferranti effect. This occurs because the capacitive shunt current of the transmission line exceeds the load current, causing a voltage rise at the receiving end.
SIL=ZcтАЛVL2тАЛтАЛ тАФ Surge Impedance Loading
VRтАЛтЙИVSтАЛ(1+21тАЛ╧Й2LCx2) тАФ Approximate receiving end voltage at no load
In long transmission lines, the distributed shunt capacitance draws a leading charging current. When the line is lightly loaded or operating at no-load, this leading current flows through the line inductance, resulting in a voltage drop that is in phase opposition to the sending end voltage, effectively 'boosting' the voltage at the load end.
Ferranti effect is most prominent in long, unloaded or lightly loaded overhead lines.
It is negligible in short transmission lines due to lower shunt capacitance.
The phenomenon is fundamentally caused by the interaction of line inductance and shunt capacitance.
Shunt reactors are typically used at the receiving end to mitigate this voltage rise.
Over-voltage stress on insulators and equipment at the receiving end.
Potential damage to transformers and connected loads.
Design of shunt compensation systems for extra-high voltage (EHV) lines.
Surge Impedance Loading (SIL) is the power delivered by a line to a purely resistive load equal to its surge impedance.
When load current is exactly equal to the charging current, the voltage profile remains relatively flat.
B is correct тАФ The receiving end voltage is higher than the sending end voltage when the load current is less than the capacitive charging current of the line.
Always remember that shunt capacitors improve power factor but exacerbate the Ferranti effect, whereas shunt reactors are used specifically to counteract it.