Substation Design interview questions

1. A.one-line representation of the three-phase system showing transformers, breakers, isolators, CTs, PTs and protection, the master drawing of any substation
2. B.gas-insulated switchgear needs about 10–20% of the air-insulated footprint and suits polluted or urban sites, at higher capital cost and SF6 handling duties
3. C.the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
4. D.an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks

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1. A.Main and transfer bus
2. B.Single line diagram
3. C.Bay
4. D.Switchyard shielding

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1. A.Single line diagram — the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
2. B.Single line diagram — minimum air distance from live parts to earthed structures, about 1300 mm at 132 kV, 2100 mm at 220 kV and 3500 mm at 400 kV
3. C.Single line diagram — an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks
4. D.Single line diagram — one-line representation of the three-phase system showing transformers, breakers, isolators, CTs, PTs and protection, the master drawing of any substation

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1. A.the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
2. B.grid conductor sized on fault current and duration, then mesh and step voltages are checked against tolerable limits from body weight and gravel resistivity
3. C.minimum air distance from live parts to earthed structures, about 1300 mm at 132 kV, 2100 mm at 220 kV and 3500 mm at 400 kV
4. D.transfer bus with a bus coupler lets a feeder breaker be taken out for maintenance while the feeder stays supplied, common at 132 kV

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1. A.Main and transfer bus
2. B.GIS vs AIS
3. C.Double bus single breaker
4. D.Isolator vs breaker

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1. A.Main and transfer bus — the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
2. B.Main and transfer bus — transfer bus with a bus coupler lets a feeder breaker be taken out for maintenance while the feeder stays supplied, common at 132 kV
3. C.Main and transfer bus — each feeder can be transferred between two main buses by isolators, allowing bus maintenance without feeder outage but breaker maintenance needs one
4. D.Main and transfer bus — three breakers per two circuits between two main buses, giving no feeder outage for any breaker fault, standard at 400 kV and above

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1. A.the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
2. B.transfer bus with a bus coupler lets a feeder breaker be taken out for maintenance while the feeder stays supplied, common at 132 kV
3. C.an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks
4. D.each feeder can be transferred between two main buses by isolators, allowing bus maintenance without feeder outage but breaker maintenance needs one

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1. A.Isolator vs breaker
2. B.Main and transfer bus
3. C.Bay
4. D.One-and-a-half breaker scheme

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1. A.Bay — transfer bus with a bus coupler lets a feeder breaker be taken out for maintenance while the feeder stays supplied, common at 132 kV
2. B.Bay — the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
3. C.Bay — minimum air distance from live parts to earthed structures, about 1300 mm at 132 kV, 2100 mm at 220 kV and 3500 mm at 400 kV
4. D.Bay — an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks

Answer + AI explanation with Pro

1. A.overhead earth wires or masts placed so the rolling-sphere or 30–45° protective-angle zone covers every live conductor per IS/IEC 62305
2. B.an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks
3. C.the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
4. D.three breakers per two circuits between two main buses, giving no feeder outage for any breaker fault, standard at 400 kV and above

Answer + AI explanation with Pro

1. A.Isolator vs breaker
2. B.GIS vs AIS
3. C.Switchyard shielding
4. D.Main and transfer bus

Answer + AI explanation with Pro

1. A.Isolator vs breaker — three breakers per two circuits between two main buses, giving no feeder outage for any breaker fault, standard at 400 kV and above
2. B.Isolator vs breaker — selecting equipment withstand levels (BIL/SIL) against surge arrester protective levels with a margin of at least 20% per IEC 60071
3. C.Isolator vs breaker — the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
4. D.Isolator vs breaker — an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks

Answer + AI explanation with Pro

1. A.transfer bus with a bus coupler lets a feeder breaker be taken out for maintenance while the feeder stays supplied, common at 132 kV
2. B.each feeder can be transferred between two main buses by isolators, allowing bus maintenance without feeder outage but breaker maintenance needs one
3. C.three breakers per two circuits between two main buses, giving no feeder outage for any breaker fault, standard at 400 kV and above
4. D.grid conductor sized on fault current and duration, then mesh and step voltages are checked against tolerable limits from body weight and gravel resistivity

Answer + AI explanation with Pro

1. A.Phase-to-earth clearance
2. B.Isolator vs breaker
3. C.Main and transfer bus
4. D.One-and-a-half breaker scheme

Answer + AI explanation with Pro

1. A.One-and-a-half breaker scheme — grid conductor sized on fault current and duration, then mesh and step voltages are checked against tolerable limits from body weight and gravel resistivity
2. B.One-and-a-half breaker scheme — gas-insulated switchgear needs about 10–20% of the air-insulated footprint and suits polluted or urban sites, at higher capital cost and SF6 handling duties
3. C.One-and-a-half breaker scheme — three breakers per two circuits between two main buses, giving no feeder outage for any breaker fault, standard at 400 kV and above
4. D.One-and-a-half breaker scheme — the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout

Answer + AI explanation with Pro

1. A.one-line representation of the three-phase system showing transformers, breakers, isolators, CTs, PTs and protection, the master drawing of any substation
2. B.overhead earth wires or masts placed so the rolling-sphere or 30–45° protective-angle zone covers every live conductor per IS/IEC 62305
3. C.gas-insulated switchgear needs about 10–20% of the air-insulated footprint and suits polluted or urban sites, at higher capital cost and SF6 handling duties
4. D.each feeder can be transferred between two main buses by isolators, allowing bus maintenance without feeder outage but breaker maintenance needs one

Answer + AI explanation with Pro

1. A.Double bus single breaker
2. B.GIS vs AIS
3. C.Phase-to-earth clearance
4. D.Main and transfer bus

Answer + AI explanation with Pro

1. A.Double bus single breaker — each feeder can be transferred between two main buses by isolators, allowing bus maintenance without feeder outage but breaker maintenance needs one
2. B.Double bus single breaker — the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
3. C.Double bus single breaker — minimum air distance from live parts to earthed structures, about 1300 mm at 132 kV, 2100 mm at 220 kV and 3500 mm at 400 kV
4. D.Double bus single breaker — transfer bus with a bus coupler lets a feeder breaker be taken out for maintenance while the feeder stays supplied, common at 132 kV

Answer + AI explanation with Pro

1. A.the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
2. B.minimum air distance from live parts to earthed structures, about 1300 mm at 132 kV, 2100 mm at 220 kV and 3500 mm at 400 kV
3. C.an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks
4. D.gas-insulated switchgear needs about 10–20% of the air-insulated footprint and suits polluted or urban sites, at higher capital cost and SF6 handling duties

Answer + AI explanation with Pro

1. A.Switchyard shielding
2. B.Main and transfer bus
3. C.GIS vs AIS
4. D.Phase-to-earth clearance

Answer + AI explanation with Pro

1. A.Phase-to-earth clearance — an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks
2. B.Phase-to-earth clearance — selecting equipment withstand levels (BIL/SIL) against surge arrester protective levels with a margin of at least 20% per IEC 60071
3. C.Phase-to-earth clearance — grid conductor sized on fault current and duration, then mesh and step voltages are checked against tolerable limits from body weight and gravel resistivity
4. D.Phase-to-earth clearance — minimum air distance from live parts to earthed structures, about 1300 mm at 132 kV, 2100 mm at 220 kV and 3500 mm at 400 kV

Answer + AI explanation with Pro

1. A.grid conductor sized on fault current and duration, then mesh and step voltages are checked against tolerable limits from body weight and gravel resistivity
2. B.transfer bus with a bus coupler lets a feeder breaker be taken out for maintenance while the feeder stays supplied, common at 132 kV
3. C.one-line representation of the three-phase system showing transformers, breakers, isolators, CTs, PTs and protection, the master drawing of any substation
4. D.selecting equipment withstand levels (BIL/SIL) against surge arrester protective levels with a margin of at least 20% per IEC 60071

Answer + AI explanation with Pro

1. A.Main and transfer bus
2. B.Single line diagram
3. C.IEEE 80 earthing mat design
4. D.Bay

Answer + AI explanation with Pro

1. A.IEEE 80 earthing mat design — grid conductor sized on fault current and duration, then mesh and step voltages are checked against tolerable limits from body weight and gravel resistivity
2. B.IEEE 80 earthing mat design — selecting equipment withstand levels (BIL/SIL) against surge arrester protective levels with a margin of at least 20% per IEC 60071
3. C.IEEE 80 earthing mat design — an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks
4. D.IEEE 80 earthing mat design — one-line representation of the three-phase system showing transformers, breakers, isolators, CTs, PTs and protection, the master drawing of any substation

Answer + AI explanation with Pro

1. A.gas-insulated switchgear needs about 10–20% of the air-insulated footprint and suits polluted or urban sites, at higher capital cost and SF6 handling duties
2. B.each feeder can be transferred between two main buses by isolators, allowing bus maintenance without feeder outage but breaker maintenance needs one
3. C.the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
4. D.overhead earth wires or masts placed so the rolling-sphere or 30–45° protective-angle zone covers every live conductor per IS/IEC 62305

Answer + AI explanation with Pro

1. A.Phase-to-earth clearance
2. B.GIS vs AIS
3. C.One-and-a-half breaker scheme
4. D.Insulation coordination

Answer + AI explanation with Pro

1. A.GIS vs AIS — the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout
2. B.GIS vs AIS — minimum air distance from live parts to earthed structures, about 1300 mm at 132 kV, 2100 mm at 220 kV and 3500 mm at 400 kV
3. C.GIS vs AIS — selecting equipment withstand levels (BIL/SIL) against surge arrester protective levels with a margin of at least 20% per IEC 60071
4. D.GIS vs AIS — gas-insulated switchgear needs about 10–20% of the air-insulated footprint and suits polluted or urban sites, at higher capital cost and SF6 handling duties

Answer + AI explanation with Pro

1. A.selecting equipment withstand levels (BIL/SIL) against surge arrester protective levels with a margin of at least 20% per IEC 60071
2. B.gas-insulated switchgear needs about 10–20% of the air-insulated footprint and suits polluted or urban sites, at higher capital cost and SF6 handling duties
3. C.an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks
4. D.one-line representation of the three-phase system showing transformers, breakers, isolators, CTs, PTs and protection, the master drawing of any substation

Answer + AI explanation with Pro

1. A.Single line diagram
2. B.GIS vs AIS
3. C.Double bus single breaker
4. D.Insulation coordination

Answer + AI explanation with Pro

1. A.Insulation coordination — three breakers per two circuits between two main buses, giving no feeder outage for any breaker fault, standard at 400 kV and above
2. B.Insulation coordination — selecting equipment withstand levels (BIL/SIL) against surge arrester protective levels with a margin of at least 20% per IEC 60071
3. C.Insulation coordination — an isolator is an off-load device giving visible isolation and must be operated only after the breaker has opened, enforced by interlocks
4. D.Insulation coordination — the set of breaker, isolators, CTs, PT and earth switch controlling one circuit, whose width and depth fix the switchyard layout

Answer + AI explanation with Pro