2A Power Distribution

Radial Distribution

A separate feeder is used to feed power from the substation to each area and this feeder feeds power to a distributor in one direction only

Ring Distribution

The distribution transformer is connected in a loop and supplied by a substation from one end. It means each distribution transformer has two different ways to connect with the substation

Radial Distribution

Type of distribution network characterized by a single line feeder . . .

a. Reactive . . .

What is the purpose of static condenser? a. Reactive . . . b. Voltage regulator c. AC to DC converter d. Regulates current

a. Current is directly proportional to transmission current and square of the distance

Power supply network characteristic. . . a. Current is directly proportional to transmission current and square of the distance b. proportional to transmission current and distance c. Single phase cannot be converted into 3 phase using inverter d. Increasing transmission voltage to reduce conductor requirements

a. Installing low power factor correction

Solution for low power factor?

Primary

A type of alarm that will automatically shutdown the system

b. Power loss due to transmission . . .

Principles of power supply network except: a. Three phase power . . . b. Power loss due to transmission . . . c. A single phase cannot be converted . . . d. Increasing the transmission voltage . . .

Instrument Transformer

Type of transformer used as transducer

Poles

All are the same except?

ICAO Doc 9157

An ICAO document that contains the power supply standards requirements for an Aerodrome?

Mechanical Interlock

It is a mechanical device provided on each of the main Auto-transfer breaker, as a gadget to prevent two or more breakers to closed at the same time

2405 A

Ifl @ Secondary, combi (200kVA @ 34.5/19/92 – 0.48/0.277 kV)

Time Delay Breaking

It is commonly known as short time circuit breaker setting (100% - 110% for 0.05 sec – 0.4 sec)

11,000 V

What is the National Grid standard low voltage distribution voltage?

Zigzag Transformer

Transformer which provides neutral grounding derived from delta transformation

Overload Switch

Which of the following is not a current protection device

Overload Trip

It is commonly known as long time circuit breaker setting (80% - 100% for 0.5 sec -20sec)

conductor

Increasing the transmission voltage will decrease the current and minimized the power loss in transmission lines and also decreases its ______ requirements

D. POLES

When Gen 1 transfers to Gen 2, which of the following parameters will change? A. VOLTAGE B. FREQUENCY C. PHASE D. POLES

Positive, Negative, zero sequence

Symmetrical component of current

Load Break Switch

Switches that are provided with an interrupting device capable of disconnecting circuits under load

Prime mover

Any mechanical device used to drive a generator to produce electricity

Distribute power to the consumer

What is the purpose of power distribution system?

Vaults and shelter

Installed within the aerodrome for the protection of electrical equipment against weather and for better security

reroute

The engineers at the central control of the National Grid Network continually asses the demand, direct the flow and ______ electrical energy when breakdown occurs

Short Circuit

There are two conductors having different voltage, what happens when these conductors touch each other?

Poles

Parallel Generator

297.36 KVAR

S=1000 KVA, pf1=0.68, pf2=0.90. Compute for the power factor

Intensity of light

The “maximum switch over time” is defined as the duration for the measured _____ to fall from 50% of the original value and recover to 50% during a power supply changeover

2000 – 5500 V

The voltage is reduced at the aerodrome substation to an intermediate voltage for distribution. What is the range of an intermediate voltage?

33,000 V

What is the National Grid standard network distribution voltage?

Surge Protective Device

It is a protective device designed to protect electrical equipment loads against the damaging effects of transient voltages that can be induced or generated as a result of remote lightning, power equipment switching or high frequency disturbances

Uninterruptible Loads

It include all CNS equipment, critical airfield lightings (1 sec maximum transfer time), alarms, protection devices, and computers, wherein power interruption may result to an accident, serious incident, life threat or financial loss.

Runway Visual Range less than 800 m

Aerodromes that will require a stipulated transfer time of 1 second for the IPU to be brought into operation

228.75 V

A Panel Board 238 V (L-L) at its bus bar. Supplying power to a 3-phase load with a balanced current of 15 A through a 3 – 2.0 mm2 THHN wire at a length 35 meters. What will be the load terminal voltage? Assume R(wire) = 3.1 ohms/305 m and X(wire) = 0.073 ohms/305 m from line to neutral

24 – 72 hours

Engine-generator sets are often expected to operate without refueling for how many hours?

Synchronizer

What is the device used to simultaneously load two or more AC power sources?

D. Voltage Regulator

Primary purpose of substation in a power distribution system? A. Power Distribution B. Power Transmission C. Energy Storage D. Voltage Regulator

230.94 V

Given 400 V/√3 , solve for the secondary voltage

Grid distribution (GRID or MESH distribution ay same lang)

What type of distribution system has a central substation and distributes power to the multiple interconnected substation? A. Radial Distribution B. Ring Distribution C. Interconnected Distribution D. Grid Distribution

80 batteries

48 V, 12-V, 3 A, 108 AH battery, 30 days. How many batteries are needed?

over 5000 V

Power to the aerodrome main power substation is usually supplied at a high voltage

Overload Relay

Not considered as protective device

Independent

For major airports, it is desirable to have at least two incoming power sources must be ___

22 KA

Isc @ secondary, neglecting conductor: 100 KVA, 34.5 – 0.46 KV, 5.70% Z, heater load at 70%

7 A

3 phase (Vp = 34.5 KV, Vs = 230 V, Is= 1050 A) Solve for primary current

38.51

12.9 HP, divide all given then divide by √3

0.01 per unit

1000 KVA, 0.001 pu, 100 KVA

Install power factor conversion capacitor

Which soluton is commonly employed to improve a low power factor in an electrical system?

870 KVA

3-500 KVA, Y-Y connection Solve for the maximum power that can be generated if one 500 KVA is removed (ganyan ang thought, basta yan)