"美军接口标准MIL-STD-704F：飞机电源特性综述" - CSDN文库

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MIL-STD-704F

f.

NATO

g.

POR

h.

RMS

i.

STANAG

j.

VA

North

Atlantic

Treaty

Organization

Point

of

Regulation

Root

Mean

Square

Standardization

Agreement

Volt-ampere

3.2

Abnomial

opeTation

.

Abnormal

operation

occurs

when

a

malfunction

or

failure

in

the

electric

system

has

taken

place

and

the

protective

devices

of

the

system

are

operating

to

remove

the

malfunction

or

failure

from

the

remainder

of

the

system

before

the

limits

for

abnormal

operation

are

exceeded.

The

power

source

may

operate

in

a

degraded

mode

on

a

continuous

basis

where

the

power

characteristics

supplied

to

the

utilization

equipment

exceed

normal

operation

limits

but

remain

within

the

limits

for

abnormal

operation.

3.3

AC

voltage

.

AC

voltage

is

the

root

mean

square

(RMS)

phase

to

neutral

value

for

each

half

cycle.

a.

Steady

state

AC

voltage

is

the

time

average

of

the

RMS

voltage

over

a

period

not

to

exceed

one

second.

b.

Peak

AC

voltage

is

the

maximum

absolute

value

of

the

instantaneous

voltage.

c.

The

direct

current

(DC)

component

of

the

AC

voltage

is

the

average

value

of

the

voltage.

3.4

Aircraft

electric

power

systems

.

An

aircraft

electric

power

system

consists

of

a

main

power

source,

emergency

power

source,

power

conversion

equipment,

control

and

protection

devices,

and

an

interconnection

network

(wires,

cables,

connectors,

etc.).

The

main

power

is

derived

from

aircraft

generators

driven

by

the

aircraft

propulsion

engines.

Emergency

power

is

derived

from

batteries,

engine

bleed

air,

independent

auxiliary

power

units,

ram

air

driven

generators,

or

hydraulically

driven

generators.

3.5

Crest

factor

.

The

crest

factor

is

the

absolute

value

of

the

ratio

of

the

peak

to

the

RMS

value

for

each

half

cycle

of

the

voltage

waveform.

3.6

Current

.

Alternating

Current

(AC)

current

is

the

RMS

value

for

one

half

cycle

measured

between

consecutive

zero

crossings

of

the

fundamental

frequency

component.

Direct

Current

(DC)

current

is

the

instantaneous

value.

3.7

Current

modulation

.

Current

modulation

is

the

difference

between

maximum

current

and

minimum

current.

Percent

current

modulation

is

the

ratio

of

the

current

modulation

to

the

average

(mean

for

DC,

RMS

of

the

fundamental

for

AC)

current

multiplied

by

100

over

a

one

second

period.

3.8

DC

voltage

.

Steady

state

DC

voltage

is

the

time

average

of

the

instantaneous

DC

voltage

over

a

period

not

to

exceed

one

second.

2

MIL-STD-704F

3.9

DistOTtion

.

AC

distortion

is

the

RMS

value

of

the

AC

waveform

exclusive

of

the

fundamental.

In

a

DC

system,

DC

distortion

is

the

RMS

value

of

the

alternating

voltage

component

on

the

DC

voltage.

3.10

DistOTtion

factor

.

The

AC

distortion

factor

is

the

ratio

of

the

AC

distortion

to

the

RMS

value

of

the

fundamental

component.

The

DC

distortion

factor

is

the

ratio

of

the

DC

distortion

to

the

DC

steady

state

voltage.

3.11

Distortion

spectrum

.

The

distortion

spectrum

quantifies

AC

or

DC

distortion

in

terms

of

the

amplitude

of

each

frequency

component.

The

distortion

spectrum

includes

the

components

resulting

from

amplitude

and

frequency

modulation

as

well

as

harmonic

and

non



harmonic

components

of

the

waveform.

3.12

Electric

starting

operation

.

Electric

starting

operation

is

a

specialized

case

of

normal

electric

system

operating

conditions

where

the

normal

voltage

limits

may

be

exceeded

due

to

the

high

electric

demand.

The

voltage

limits

for

normal

operation

may

be

exceeded

during

the

following

starting

conditions:

a.

An

electric

start

of

the

propulsion

engine.

(Battery

power,

aircraft

DC

power

or

external

power

applied

on

the

aircraft

bus.)

b.

A

battery

start

of

an

auxiliary

power

unit.

3.13

Emergency

operation

.

Emergency

operation

occurs

following

the

loss

of

the

main

generating

equipment

when

a

limited

electric

source,

independent

of

the

main

system,

is

used

to

power

a

reduced

complement

of

distribution

and

utilization

equipment

selected

to

maintain

flight

and

personnel

safety.

3.14

External

power

source

.

The

external

power

source

refers

to

the

ground

or

shipboard

power

source

used

to

provide

power

to

the

aircraft's

electrical

distribution

system.

3.15

Frequency

.

Frequency

is

the

reciprocal

of

the

period

of

the

AC

voltage

waveform.

The

unit

of

frequency

is

Hertz

(Hz).

Steady

state

frequency

is

the

time

average

of

the

frequency

over

a

period

not

to

exceed

one

second.

3.16

Frequency

modulation

.

Frequency

modulation

is

the

difference

between

the

maximum

and

minimum

frequency

values

that

occur

in

a

one-minute

period

during

steady

state

operating

conditions.

Frequency

modulation

is

a

measure

of

the

stability

of

the

power

system's

frequency

regulation.

3.17

Load

unbalance

.

Load

unbalance

for

a

three-phase

load

is

the

difference

between

the

highest

and

lowest

phase

loads.

3.18

Nomial

opeTation

.

Normal

operation

occurs

when

the

system

is

operating

as

intended

in

the

absence

of

any

fault

or

malfunction

that

degrades

performance

beyond

established

requirements.

It

includes

all

system

functions

required

for

aircraft

operation

except

3

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