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Series reactors have
Low impedance
Low resistance
Low reactance
High resistance
Low resistance
Series reactors are inductive devices connected in series with power system components to limit fault currents. They must possess high inductive reactance (XLтАЛ) to restrict short-circuit currents, but they are specifically designed with low resistance (R) to minimize I2R power losses and prevent excessive voltage drops during normal operating conditions.
Series reactors are inductive devices connected in series with power system components to limit fault currents. They must possess high inductive reactance (XLтАЛ) to restrict short-circuit currents, but they are specifically designed with low resistance (R) to minimize I2R power losses and prevent excessive voltage drops during normal operating conditions.
Z=R2+XL2тАЛтАЛ тАФ Total impedance of a reactor
PlossтАЛ=I2R тАФ Power loss due to resistance
The principle relies on the impedance formula Z=R+jXLтАЛ. During a fault, the sudden surge of current is restricted by the high reactance jXLтАЛ. By keeping R as low as possible, the steady-state thermal losses are minimized, ensuring high efficiency in high-voltage transmission lines.
Series reactors are primarily used to limit short-circuit currents in large power systems.
The inductive reactance (XLтАЛ) is designed to be much higher than the resistance (R).
They are often used to protect circuit breakers by reducing the breaking duty.
High resistance would lead to excessive heating and voltage regulation issues.
Reduces current limiting requirements for circuit breakers
High efficiency due to minimal active power dissipation
Causes a voltage drop across the line
Increases the total reactive power consumption of the grid
Busbar sectionalizing
Feeder protection in transmission substations
Short-circuit current limitation in industrial power plants
A series reactor acts as a 'choke' to high-frequency or high-magnitude fault currents while appearing almost transparent to standard 50Hz/60Hz load currents.
If the resistance were high, the reactor would act like a heating element, which is undesirable in transmission lines.
B is correct тАФ Series reactors are designed with low resistance to ensure that power losses and steady-state voltage drops remain minimal during standard operation.
Always remember that in power engineering, 'ideal' protective components minimize real power loss (I2R) while maximizing reactive control (XLтАЛ or BCтАЛ).