MES Departmental • 2026 • Engineering Paper-II
What is the standard assumed indoor condition for human comfort when sufficient data is not available?
A)
40°C DBT and 75% RH
B)
25°C DBT and 80% RH
C)
21°C DBT and 50% RH
D)
30°C DBT and 70% RH
Option C is correct: 21°C DBT and 50% RH.
MES Departmental • 2026 • Engineering Paper-II
What is the standard minimum ground clearance required for Low Tension (LT) and medium voltage lines crossing a street?
A)
4.5 meters
B)
5.8 meters
C)
6.1 meters
D)
7.2 meters
Option B is correct: 5.8 meters.
MES Departmental • 2026 • Engineering Paper-II
Which compressor control strategy involves stopping the motor when the target system pressure is reached, and restarting it when pressure drops?
A)
Variable Speed Drive (VSD) control
B)
Constant speed control with blow-off
C)
Start/Stop control
D)
Suction throttling
Option C is correct: Start/Stop control.
MES Departmental • 2026 • Engineering Paper-II
From an economic and practical standpoint, what is the ideal location for a distribution substation?
A)
Far away from residential areas to avoid electromagnetic fields.
B)
Exactly at the geographical center of the city.
C)
At the load center.
D)
Right next to the primary generating station.
Option C is correct: At the load center..
MES Departmental • 2026 • Engineering Paper-II
Why are gas turbines frequently used in power grids for “peaking” applications?
A)
They have high capital costs but run efficiently at baseloads
B)
They take hours to synchronize with the power grid
C)
They have fast start-up times and can quickly meet peak electricity demands
D)
They do not require a compressor to operate
Option C is correct: They have fast start-up times and can quickly meet peak electricity demands.
MES Departmental • 2026 • Engineering Paper-II
The function of a conservator in a power transformer is to:
A)
protect against internal faults.
B)
cool the transformer oil.
C)
provide physical support to the core.
D)
take care of the expansion and contraction of transformer oil due to temperature variation.
Option D is correct: take care of the expansion and contraction of transformer oil due to temperature variation..
MES Departmental • 2026 • Engineering Paper-II
Which soil type consistently shows the lowest resistivity value, making it naturally ideal for electrical grounding?
A)
Dry sand
B)
Solid granite rock
C)
Clay or moist loamy soil
D)
Gravel beds
Option C is correct: Clay or moist loamy soil.
MES Departmental • 2026 • Engineering Paper-II
What is the minimum standard vertical ground clearance required for 33 kV lines crossing over public roads?
A)
4.5 meters
B)
5.5 meters
C)
6.1 meters
D)
7.5 meters
Option C is correct: 6.1 meters.
MES Departmental • 2026 • Engineering Paper-II
What is the most common cause of premature failure of pin insulators on 11kV lines?
A)
Accumulation of dust, salt, or industrial pollution causing leakage currents and flashovers
B)
Over-voltage in the system
C)
High ambient temperature in the summer
D)
High frequency AC transmission
Option A is correct: Accumulation of dust, salt, or industrial pollution causing leakage currents and flashovers.
MES Departmental • 2026 • Engineering Paper-II
What type of core transformer configuration is typically used in a grid distribution substation to provide a safe neutral wire for domestic consumer single-phase loads?
A)
Delta–Delta (-) connection.
B)
Star–Star (Y-Y) connection.
C)
Delta–Star (-Y) step-down connection.
D)
Open-Delta (V-V) connection
Option C is correct: Delta–Star (-Y) step-down connection..
MES Departmental • 2026 • Engineering Paper-II
What happens to the operating time of an IDMT (Inverse Definite Minimum Time) overcurrent relay as the fault current increases?
A)
Time increases
B)
Time remains constant
C)
Time decreases
D)
Relay goes into bypass mode
Option C is correct: Time decreases.
MES Departmental • 2026 • Engineering Paper-II
Which instrument is primarily used to measure the insulation resistance of a transformer?
A)
Multimeter
B)
Megger
C)
Voltmeter
D)
Ammeter
Option B is correct: Megger.
MES Departmental • 2026 • Engineering Paper-II
Why is a Magnetic Balance Test conducted on a three-phase transformer during pre-commissioning?
A)
To calculate the total copper losses at full load
B)
To check for inter-turn shorts, core unbalance, or physical displacement of the windings
C)
To evaluate the speed of the cooling fan motors
D)
To measure the insulation resistance of the neutral bushing
Option B is correct: To check for inter-turn shorts, core unbalance, or physical displacement of the windings.
MES Departmental • 2026 • Engineering Paper-II
How is the primary winding of a Potential Transformer (PT/CVT) connected to the line?
A)
In series with the load
B)
In parallel (across the phase and neutral or phase to phase)
C)
In delta connection only
D)
Through a current limiting resistor
Option B is correct: In parallel (across the phase and neutral or phase to phase).
MES Departmental • 2026 • Engineering Paper-II
Is it dangerous to leave the secondary of a PT open-circuited?
A)
Yes, it will produce a high voltage and cause a flashover
B)
No, a PT is a voltage source and is designed to operate with an open secondary (no load)
C)
Yes, it will damage the primary winding
D)
No, it will only damage the core
Option B is correct: No, a PT is a voltage source and is designed to operate with an open secondary (no load).
MES Departmental • 2026 • Engineering Paper-II
How is a power transformer protected from indirect lightning strikes or induced overvoltages?
A)
By using overcurrent relays
B)
By using overhead ground wires (shield wires)
C)
By using Differential protection
D)
By using conservator tanks
Option B is correct: By using overhead ground wires (shield wires).
MES Departmental • 2026 • Engineering Paper-II
In terms of heat transfer, what is equivalent to “One Ton of Refrigeration”?
A)
The heat required to melt 1 ton of ice at 0°C in 24 hours
B)
The cooling required to freeze 1 ton of water into ice at 0°C in 24 hours
C)
The heat absorbed by the evaporator in one minute
D)
The rate of heat transferred in 1 hour
Option A is correct: The heat required to melt 1 ton of ice at 0°C in 24 hours.
MES Departmental • 2026 • Engineering Paper-II
What is the primary purpose of a Current Transformer (CT) in a substation?
A)
To step down voltage for energy meters.
B)
To step down current to a safe, measurable value (e.g., 5A or 1A).
C)
To interrupt fault currents.
D)
To measure the insulation resistance.
Option B is correct: To step down current to a safe, measurable value (e.g., 5A or 1A)..
MES Departmental • 2026 • Engineering Paper-II
In a C&R panel, what is the standard secondary rating of a standard protection Current Transformer?
A)
500 A or 200 A
B)
5A or 1A
C)
110V or 220V
D)
50Hz or 60Hz
Option B is correct: 5A or 1A.
MES Departmental • 2026 • Engineering Paper-II
What is the fundamental principle of a Percentage Differential Relay used in transformers?
A)
Measures the voltage drop across the line.
B)
Compares currents entering and leaving the protected zone.
C)
Senses changes in ambient temperature.
D)
Operates based on the frequency of the system
Option B is correct: Compares currents entering and leaving the protected zone..
MES Departmental • 2026 • Engineering Paper-II
What type of speed variation does a flywheel control?
A)
Variation of speed over a long duration
B)
Intermittent fluctuations within a cycle (cyclic variations)
C)
Speed variations caused by sudden load changes
D)
Non-uniform load torque variations
Option B is correct: Intermittent fluctuations within a cycle (cyclic variations).
MES Departmental • 2026 • Engineering Paper-II
Which type of distance relay is inherently directional and suited for long transmission lines?
A)
Impedance Relay
B)
Reactance Relay
C)
Mho Relay
D)
Plain Overcurrent Relay
Option C is correct: Mho Relay.
MES Departmental • 2026 • Engineering Paper-II
How is an ammeter connected in a panel wiring circuit?
A)
In parallel with the load
B)
In series with the load
C)
Across the voltage transformer
D)
Through a high resistance multiplier
Option B is correct: In series with the load.
MES Departmental • 2026 • Engineering Paper-II
In the 3-pole Fall-of-Potential method, what is the mathematically ideal distance for placing the potential probe (P)?
A)
50% of the total distance to the current probe
B)
62% of the total distance to the current probe
C)
90% of the total distance to the current probe
D)
Directly halfway between the grid and current probe
Option B is correct: 62% of the total distance to the current probe.
MES Departmental • 2026 • Engineering Paper-II
When looking to purchase a domestic refrigerator for home use, how is the capacity typically measured?
A)
Kilowatts per day
B)
Cubic feet (CFT) or Liters
C)
Horsepower
D)
British Thermal Units (BTU)
Option B is correct: Cubic feet (CFT) or Liters.
