Power Systems interview questions

1. A.the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series
2. B.expressing quantities as fractions of chosen base values so transformer turns ratios vanish and impedances across voltage levels become comparable
3. C.receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
4. D.graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area

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1. A.Per-unit system
2. B.Corona
3. C.Surge impedance loading
4. D.Newton-Raphson load flow

Answer + AI explanation with Pro

1. A.Per-unit system — iterative method using the Jacobian of power mismatches that converges quadratically in a few iterations regardless of system size
2. B.Per-unit system — ionisation of the air around a conductor when its surface gradient exceeds about 30 kV/cm peak, causing loss, audible noise and ozone
3. C.Per-unit system — M d²δ/dt² equals Pm minus Pe, relating rotor angle acceleration to the mismatch between mechanical input and electrical output
4. D.Per-unit system — expressing quantities as fractions of chosen base values so transformer turns ratios vanish and impedances across voltage levels become comparable

Answer + AI explanation with Pro

1. A.receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
2. B.M d²δ/dt² equals Pm minus Pe, relating rotor angle acceleration to the mismatch between mechanical input and electrical output
3. C.graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
4. D.iterative method using the Jacobian of power mismatches that converges quadratically in a few iterations regardless of system size

Answer + AI explanation with Pro

1. A.Swing equation
2. B.Ferranti effect
3. C.Newton-Raphson load flow
4. D.Per-unit system

Answer + AI explanation with Pro

1. A.Ferranti effect — resolution of an unbalanced three-phase set into positive, negative and zero sequence sets so unsymmetrical faults can be analysed
2. B.Ferranti effect — iterative method using the Jacobian of power mismatches that converges quadratically in a few iterations regardless of system size
3. C.Ferranti effect — receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
4. D.Ferranti effect — expressing quantities as fractions of chosen base values so transformer turns ratios vanish and impedances across voltage levels become comparable

Answer + AI explanation with Pro

1. A.ionisation of the air around a conductor when its surface gradient exceeds about 30 kV/cm peak, causing loss, audible noise and ozone
2. B.iterative method using the Jacobian of power mismatches that converges quadratically in a few iterations regardless of system size
3. C.the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series
4. D.expressing quantities as fractions of chosen base values so transformer turns ratios vanish and impedances across voltage levels become comparable

Answer + AI explanation with Pro

1. A.Single line-to-ground fault
2. B.Corona
3. C.Equal area criterion
4. D.Newton-Raphson load flow

Answer + AI explanation with Pro

1. A.Corona — graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
2. B.Corona — receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
3. C.Corona — power delivered when a lossless line is terminated in its characteristic impedance, giving a flat voltage profile and zero net reactive power
4. D.Corona — ionisation of the air around a conductor when its surface gradient exceeds about 30 kV/cm peak, causing loss, audible noise and ozone

Answer + AI explanation with Pro

1. A.receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
2. B.resolution of an unbalanced three-phase set into positive, negative and zero sequence sets so unsymmetrical faults can be analysed
3. C.graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
4. D.M d²δ/dt² equals Pm minus Pe, relating rotor angle acceleration to the mismatch between mechanical input and electrical output

Answer + AI explanation with Pro

1. A.Per-unit system
2. B.Corona
3. C.Surge impedance loading
4. D.Symmetrical components

Answer + AI explanation with Pro

1. A.Symmetrical components — power delivered when a lossless line is terminated in its characteristic impedance, giving a flat voltage profile and zero net reactive power
2. B.Symmetrical components — the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series
3. C.Symmetrical components — receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
4. D.Symmetrical components — resolution of an unbalanced three-phase set into positive, negative and zero sequence sets so unsymmetrical faults can be analysed

Answer + AI explanation with Pro

1. A.expressing quantities as fractions of chosen base values so transformer turns ratios vanish and impedances across voltage levels become comparable
2. B.M d²δ/dt² equals Pm minus Pe, relating rotor angle acceleration to the mismatch between mechanical input and electrical output
3. C.receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
4. D.the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series

Answer + AI explanation with Pro

1. A.Single line-to-ground fault
2. B.Newton-Raphson load flow
3. C.Swing equation
4. D.Corona

Answer + AI explanation with Pro

1. A.Single line-to-ground fault — resolution of an unbalanced three-phase set into positive, negative and zero sequence sets so unsymmetrical faults can be analysed
2. B.Single line-to-ground fault — graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
3. C.Single line-to-ground fault — power delivered when a lossless line is terminated in its characteristic impedance, giving a flat voltage profile and zero net reactive power
4. D.Single line-to-ground fault — the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series

Answer + AI explanation with Pro

1. A.receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
2. B.resolution of an unbalanced three-phase set into positive, negative and zero sequence sets so unsymmetrical faults can be analysed
3. C.graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
4. D.power delivered when a lossless line is terminated in its characteristic impedance, giving a flat voltage profile and zero net reactive power

Answer + AI explanation with Pro

1. A.Newton-Raphson load flow
2. B.Equal area criterion
3. C.Symmetrical components
4. D.Surge impedance loading

Answer + AI explanation with Pro

1. A.Surge impedance loading — graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
2. B.Surge impedance loading — resolution of an unbalanced three-phase set into positive, negative and zero sequence sets so unsymmetrical faults can be analysed
3. C.Surge impedance loading — ionisation of the air around a conductor when its surface gradient exceeds about 30 kV/cm peak, causing loss, audible noise and ozone
4. D.Surge impedance loading — power delivered when a lossless line is terminated in its characteristic impedance, giving a flat voltage profile and zero net reactive power

Answer + AI explanation with Pro

1. A.receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
2. B.graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
3. C.M d²δ/dt² equals Pm minus Pe, relating rotor angle acceleration to the mismatch between mechanical input and electrical output
4. D.the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series

Answer + AI explanation with Pro

1. A.Equal area criterion
2. B.Per-unit system
3. C.Corona
4. D.Swing equation

Answer + AI explanation with Pro

1. A.Equal area criterion — the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series
2. B.Equal area criterion — expressing quantities as fractions of chosen base values so transformer turns ratios vanish and impedances across voltage levels become comparable
3. C.Equal area criterion — graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
4. D.Equal area criterion — iterative method using the Jacobian of power mismatches that converges quadratically in a few iterations regardless of system size

Answer + AI explanation with Pro

1. A.iterative method using the Jacobian of power mismatches that converges quadratically in a few iterations regardless of system size
2. B.resolution of an unbalanced three-phase set into positive, negative and zero sequence sets so unsymmetrical faults can be analysed
3. C.power delivered when a lossless line is terminated in its characteristic impedance, giving a flat voltage profile and zero net reactive power
4. D.graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area

Answer + AI explanation with Pro

1. A.Swing equation
2. B.Surge impedance loading
3. C.Single line-to-ground fault
4. D.Newton-Raphson load flow

Answer + AI explanation with Pro

1. A.Newton-Raphson load flow — receiving-end voltage exceeds sending-end voltage on a lightly loaded or open long line because of the line charging capacitance
2. B.Newton-Raphson load flow — M d²δ/dt² equals Pm minus Pe, relating rotor angle acceleration to the mismatch between mechanical input and electrical output
3. C.Newton-Raphson load flow — iterative method using the Jacobian of power mismatches that converges quadratically in a few iterations regardless of system size
4. D.Newton-Raphson load flow — resolution of an unbalanced three-phase set into positive, negative and zero sequence sets so unsymmetrical faults can be analysed

Answer + AI explanation with Pro

1. A.ionisation of the air around a conductor when its surface gradient exceeds about 30 kV/cm peak, causing loss, audible noise and ozone
2. B.the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series
3. C.power delivered when a lossless line is terminated in its characteristic impedance, giving a flat voltage profile and zero net reactive power
4. D.M d²δ/dt² equals Pm minus Pe, relating rotor angle acceleration to the mismatch between mechanical input and electrical output

Answer + AI explanation with Pro

1. A.Symmetrical components
2. B.Swing equation
3. C.Equal area criterion
4. D.Per-unit system

Answer + AI explanation with Pro

1. A.Swing equation — power delivered when a lossless line is terminated in its characteristic impedance, giving a flat voltage profile and zero net reactive power
2. B.Swing equation — M d²δ/dt² equals Pm minus Pe, relating rotor angle acceleration to the mismatch between mechanical input and electrical output
3. C.Swing equation — graphical transient stability test: the machine stays in synchronism if the available decelerating area can match the accelerating area
4. D.Swing equation — the most common fault type, roughly 70–80% of line faults, analysed by connecting the three sequence networks in series

Answer + AI explanation with Pro