ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION MARCH 2017

Heating effect of current has an undesirable side effect in

• Electric oven

• immersion heater

• electric iron

• vacuum cleaner

When the sole purpose of an alternating current is to produce heat, the selection of conductor is based on _______ value of the current.

• average

• instantaneous

• root mean square

• peak

Which of the following is not included in the evaluation of the Technical Performance of a Distribution System according to Philippine Distribution Code (PDC)?

• Power Quality

• Reliability

• Collecting Efficiency

• System Efficiency

The phase angle for a series RC circuit may be computed as the angle between the __________ and __________ phasors.

• resistance, impedance

• resistance, reactance

• resistance, capacitance

• impedance, reactance

Which is not a characteristic of an ideal transformer?

• finite permeability

• infinite permeability

• no losses

• no leakage flux

It is defined as the total number of sustained Customer power interruption within a given period divided by the total number of Customers served within the same period.

• System Average Interruption Frequency Index

• System Average Interruption Duration Index

• Customer Average Interruption Frequency Index

• Customer Average Interruption Duration Index

The specific resistance ρ is defined as

• resistance of a conductor which has a length of 1 m and cross-section of 1 m2 at 20°C

• resistance of any conductor at 25°C

• resistance of a conductor which has a length of 1 m and cross-section of 1 cm2 at 20°C

The impedance triangle is similar to the __________ triangle with the resistance phasor in place of the

• Current, resistor current

• Current, resistor voltage

• voltage, impedance

• voltage, resistor voltage

What is the IEEE device function number 50?

• AC time overcurrent relay

• instantaneous overcurrent relay

• AC circuit breaker

• Differential protective relay

In long transmission line, at no-load the receiving end voltage as ccompared to the sending end voltage is

I. higher II. lower III. Remains the same

• I only

• II only

• III only

• Either I or II