Pumping Station Desing - Second Edition by Robert L. Sanks, George Tchobahoglous, Garr M. Jones

Appendix

H

Start-Up

ERIK

B.

FISKE

GEORGE

FRYE

LOWELL

G.

SLOAN

SAM V.

SUIGUSSAAR

CONTRIBUTORS

Roberts.

Benfell

E.

Robert

Bouwkamp

LeRoy

R.

Taylor

William

Young

At

the

conclusion

of the

pumping station design

and

while details

are

still

fresh

in the

mind,

the

project leader

(aided

by the

various designers

who

represent

all the

systems involved, including

the

start-up engineer) should pre-

pare

a

start-up checklist

for

each system.

The

purpose

of the

checklist

is to

make sure that

all

equipment

and

sub-

systems

are

functional

and

operate

as the

designer intended.

Do not

assume that

the

installation will

be flawless.

There have been many instances

of

incomplete

or

loose electrical connections, valves installed backward, motors

that

run in

reverse,

and

even

the

substitution

of

check valves

for

gate valves.

So

take nothing

for

granted. Make

the

start-up

check thorough

and

complete

to

avoid malfunction, damage

to

equipment,

or

future

operating problems.

Plant start-up should always

be the

responsibility

of the

contractor. Some equipment

is

almost always dam-

aged

at

start-up.

Often,

if not

usually,

the

damage

is the

result

of

installation

errors.

Even

the

most thorough

checking

by the

most knowledgeable

and

conscientious resident engineer cannot possibly forestall every error.

A

start-up team should

be

organized with

the

following suggested personnel:

•

Start-up

coordinator—an

operations specialist provided

by the

designer.

•

Electrical

engineer—provided

by the

designer.

•

Instrumentation

engineer—provided

by the

designer.

•

Resident

engineer—provided

by the

designer,

the

client,

or the

construction manager.

•

Mechanical

contractor—provided

by the

general contractor.

•

Electrical

contractor—provided

by the

general contractor.

•

Instrumentation

contractor—provided

by

general contractor.

•

Operators—provided

by the

owner.

The

duty

of the

start-up coordinator

is to

implement

the

testing plan devised

by the

consultant,

the

contractor,

and

the

owner. During

all

phases

of

testing,

the

start-up team members provide both expertise

in

their respective

fields

and

verification

checks.

After

start-up,

the

team should remain

at the job

site

to

facilitate

fine

tuning

and

debugging.

The

following

list

of

items

is

based

on

hypothetical pumping stations

of

various types.

The

list

is

intended

as

a

reminder

and

does

not

encompass every possible pumping station

or

subsystem. Several subsystems

are,

in

fact,

omitted.

For

example, ventilation,

gas

detection

(Cl

2

,

H

2

S,

explosive gases), emergency generator, odor

control,

and fluid

power systems

are so

specialized

or

specific

as to

type

and

manufacturer that

a

generalized list

might

be

inappropriate. Some parts

of the

following

list

are

generic,

and

some

are

detailed

to

emphasize

the

complexity

and the

completeness needed

for

start-up.

The

point

to be

emphasized

is

that start-up checklists

should

be

made with meticulous care

and

must

be

specific

to

each individual pumping station

and

each individ-

ual

system.

The

distinction among design, start-up,

and

troubleshooting checks

is

often

ill-defined.

The

troubleshooting

tips given

on

pages

145-148, 197-207,

and

288-292

of

Hydraulic Institute Standards

[1],

in

Table

9-1 of the

classic Pumping Manual

[2],

or on

pages

2.294-2.301

and

12.16-12.8

of

Karrasik

et

al.

[3] may

well

be

adapt-

able

to

start-up.

H-1.

Pre-Visit

Check

Before

visiting

the

pumping station, review

the

specifications, plans,

O&M

manual (control section),

and

manu-

facturers'

submittal data. Review

the

following application data.

Item

1.

Curves. System

H-Q

and

pump

performance

2.

Liquid pumped

3.

Capacity

4.

Pump mounting

5.

Number

of

pumps

and

operation strategy

(from

O&M

manual)

6.

Pump suction

7.

Pump discharge

o.

Power transmission

9.

Other power

considerations

10.

Piping

11.

Discharge check

12.

Shop tests

13.

Wet

well

Notes

Speeds, maximum heads

and

capacities,

and

design conditions.

Chemistry

of

liquid, temperature, specific gravity,

pH,

solids.

Station

influent

flow

rates, discharge rates,

and

pressure heads.

Horizontal, vertical,

or

suspended.

Sequencing, types

of

drivers

(C/S

or V/S or

combinations such

as 2 V/S and 1

C/S).

Wet

well head

or

lift

referred

to

pump datum point.

NPSH

A

versus

NPSH

R

.

Total head

in

feed

and

pounds

per

square inch

or the SI

equivalents. Obtain

the

required

time

to

close discharge valve

to

avoid water hammer.

Direct shaft-mounted coupling, intermediate

shaft,

vee-belt

drive,

etc.

Speed, motor overloading, motor

efficiency

and

power factor, station voltage, station

electrical systems

(one

or two

incoming lines

or

engine-generator power),

switchgear,

transformers,

induction

or

synchronous motors. Compare drive starting torque

to

pump

shut-off

torque,

and

effective

pumping volume versus motor

starts/hour

(responsibility

of

designer).

Flexible connections, base elbow, pipe supports, discharge air-release valve with drain

and

air

gap.

Air,

oil,

air-oil,

or

water with speed control, swing with valves spring

or

weight

and

lever,

etc.

Certified

or

witnessed. Shop test performance data that indicates speeds,

safe

(limit

lines) operating conditions,

and

NSPH

R

.

Low

wet

well level must

be

higher than

the

pump casing

and

there must

be no

vortexing

or

influent

waterfall

effect.

Otherwise,

furnish

an

automatic primer system.

[Ed.

note

—

including

such

a

feature

is the

designer's

responsibility.]

H-2. Pre-Start-Up Check

Before

start-up

of any

equipment, inspect

the

pumping station with

the

contractor,

and the

mechanical,

electrical,

and

instrumentation personnel.

The

start-up

of

complex equipment (such

as

engine-generator sets

and

variable-

speed controls) requires

a

factory representative,

so

coordinate

his

visit,

and let him

take

the

responsibility

for

his

equipment

(to

keep

manufacturers' warranties

in

force). Make sure

the

following items have been accom-

plished.

General

14.

Review

and

verify

the

resident

engineer's

inspection

checksheets.

15. All

electrical equipment

has

been installed

and

adjusted

by the

supplier

as

specified.

16. All

mechanical equipment specified

has

been installed properly

and

anchored.

All

bolts

and

nuts

are

tight.

17.

Ventilation system

is

operational.

18.

Heating system

is

operational.

19.

Sump pumps

are

operational.

20.

Instrumentation system

is

operational.

Wet

Well

21. Wet

well

is

clean.

All

debris

has

been removed.

22. Wet

well water level sensing system (e.g.,

floats,

bubbler)

has

been installed properly

and

controls have

been

adjusted

for

operating levels

as

specified.

Piping

and

Valves

23.

Suction pipe, unless submerged,

is

vacuum tight. Fasteners

are

tight

at all

pipe connections.

24.

Pipe supports

are

installed properly

and

strain

in the

equipment (particularly

in

valve bodies)

is

eliminated.

25.

Piping

is

level

or

continuously

rising to

prevent formation

of air

pockets,

and

air-relief valves

and air

bleeds

are

installed where

specified.

26.

Harness bolts

are

installed properly

in

sleeve connections (unless pipe

is

externally restrained

so

that joint

cannot

separate).

27. The

piping

has

been pressure tested

and all

pipelines

to all

equipment have been

flushed.

28.

Valves operate properly. Check

to be

sure valves (especially check valves)

are

installed

in the right flow

direction. Test limit switches

and

pressure switch operation. Bolts

on

eccentric plug valves should

be

only

tight

enough

to

prevent leakage.

29.

Valve

springs

or

lever weights

are

properly

adjusted.

Dashpots

are

properly timed.

(Do

during operational test.)

30.

Pump control

or

check valves

are

operational

and

properly timed

or

adjusted.

(Fine tune during operational test.)

31.

Both suction

and

discharge valves

are

closed.

32.

Automatic valves operate

and air

receivers

(if

any)

are

fully

charged.

33. It is

always good procedure

to

close

all

valves prior

to

beginning operational tests.

Pumps

34.

Motor

and

pump

shafts

are

disconnected

and

tested

for

alignment. Leave disconnected (see

"Motors,"

Items

53-63).

35.

Pumps

are

level

and

there

is no

strain

in the

pump casing.

36.

Packing glands

are

adjusted

with

nuts

finger

tight

for a

small, steady stream

of

water

for a

24-h break-in period.

37.

Shaft

seals

are

lubricated

as

required.

38. The

rotation arrow

on the

pump

is in

place

and

correct,

and

relate arrow

to the

direction

of the

pump dis-

charge nozzle.

Seal-Water

System

with Open

Tank

Reservoir

39.

Incoming

float

control valve

is

mounted properly.

40.

Float

can

move

freely.

41.

Incoming liquid line

to the

tank

is

furnished

with

a

shut-off

valve.

42.

Shut-off

tank drain valve

is

closed.

43.

Seal-water discharge piping

is

connected

to the

main pump.

44.

Seal-water system piping

is

furnished with

a

discharge relief

to

reservoir

for

excessive pressure.

45.

Piping

from

the

control valve

in the

tank

is

higher than

the

projected tank liquid level

(as

determined

by the

float

level).

46.

Piping

from

the

drain

is

directed

to the

sump pump.

47. A

needle valve

and a flow

indicating device

are

furnished

in the

seal-water

piping

at the

main pump.

48.

Push

the

STOP button

and

LOCKOUT button

to the

STOP

position

at the

seal-water equipment.

49.

Rotate

the

seal-water pump

shaft

by

hand.

50.

Reassemble

the

coupling

and

replace

the

coupling guard.

51. Set the

pressure switches

in the

discharge line

as

specified.

52.

Clean

and fill the

reservoir

and

adjust

the float

switch

so

water will

not

overflow.

Confirm

there

is an air gap

between

the

incoming water pipe

and the top of the

tank (for cross-connection prevention).

Motors

53.

Motor nameplate data (horsepower, speed,

and

electrical characteristics) agree with

the

specifications.

54. The

equipment (including coupling

and

gearboxes)

has

been lubricated

as

specified

by the

supplier.

55.

Confirm

that

the

coupling between

the

motor

and

pump

is

disconnected (Item 34).

"Bump"

the

motor

to

make

sure

the

direction

of

rotation

is

correct. Reconnect

the

coupling.

56.

Overload protectors

are

sized properly.

57.

Wiring connections

are

tight.

58.

Temperature overload device

is

operational.

59.

Guards

are

installed around rotating machinery.

60.

Notched belts

are

installed with proper tightness

and

alignment

in

belt drives.

61.

Alignment between pump

and

motor

shafts

is

checked.

62.

Variable-speed units: manufacturer's representative MUST

be on

site

for

start-up.

63.

Engines

and

engine-generator sets:

the

factory representative must start

up,

operate,

and

troubleshoot.

Submersible Sewage Pumps

In

addition

to the

applicable checks above, make sure

64.

Return elbows

are

securely bolted

in

place

and

fasteners

are

tight.

65.

Slide rails

are

installed properly.

A

midrail guide

is in

place

if the

depth exceeds

6 m (20

ft).

66.

Pumps seat accurately.

67.

Lifting

device

(if

included

to

remove pumps)

is

operational. Check insertion

and

removal

of

pumps. Ensure

there

are no

sharp edges

to cut

power cables.

68.

There

are NO

electrical connections, splices,

or

junction boxes

in the wet

well

or in

locations

of

condensing

humidity

69. The

leak sensor

is

operating.

70. Oil is at the

proper level

in the

rotating assembly.

H-3.

Electrical

Systems

Pre-Energizing Inspection

Electrical systems

for all

pumping stations with either low, medium,

or

high voltages

are

very dangerous.

It is

therefore

extremely important that

all

electrical checks

be

made

by

qualified

and

competent electrical inspectors

and/or engineers.

The

statement

in the

introduction that even

the

most conscientious resident

engineer

cannot

possibly prevent every error

is

particularly true

of

electrical work, where hundreds

(or

even thousands)

of

wires

must

be

properly terminated. Nevertheless,

the

engineer

can

reduce start-up problems

by

being sure that

the

fol-

lowing

electrical tests

are

made.

Before

energizing anything,

the

following should

be

done:

71. The

grounding system should

be

tested.

The

best

way to

accomplish this test

is

specified

in

IEEE

81.

The 5-

ohm

value suggested meets code

but is not

very good

for

wet-process equipment. Generally, values

of

less

than

1 ohm can be

obtained without

difficulty.

The

actual value required depends

on the

capacity

and

volt-

age

levels

of the

power system

and

should

be

determined

by the

electrical design engineer.

In

situations

where

a low

enough ground resistance cannot

be

obtained, such

as in

desert areas,

the

design engineer

should have known about

it and

designed

a

ground

mat for the

facility

that would,

at

least, hold potential

gradients

within

values

safe

to

human beings. Check switchgear, yard transformer, pump

and

motor control

centers, motor feeder cables, pumps

and

equipment

at all

electrically connected panels,

and

switchgear

ground

bus for

grounding.

72.

Electrical insulation should

be

tested.

For

low-voltage

(<600

V),

this

is

easily accomplished with meg-ohm

meters that typically apply 1000

V to the

circuitry under test.

For

systems rated over

600 V,

"high-potting"

is

required. Only personnel trained

in

these procedures should attempt high-voltage insulation testing.

73.

Protective devices, such

as

fuses

and

circuit breakers, should

be

checked

at

least visually

for

conformance

to

design documents. Circuit breakers should

be

operated manually

to

ensure that

the

mechanisms

are not

binding. Adjustable circuit breakers

and

protective relays should

be

checked

for

correct settings. Checking

low-voltage motor overload heaters

and

motor starter

fuses

is

specifically omitted

at

this point. Overload

heater

and

motor starter

fuses

should

be

removed

from

all

starters before energizing

the

system. High-volt-

age

starters

and

circuit breakers should

be

racked

out to the

test positions.

In

power systems rated more than 1200

A at 480 V and all

power systems operating

at

over

600 V, it is

strongly recommended that

all

protective

devices

be

tested

by

passing current through

their

sensing ele-

ments

with

a

high-current low-voltage testing

machine—a

task that should normally

be

done

by

contractors

specializing

in

electrical testing.

74.

Electrical gear must

be

vacuumed

out

thoroughly

to

remove construction dust

and

debris.

75.

Every circuit

and

breaker

and

disconnect switch should

be

opened before

the

utility turns

on the

power.

Some

of the

detailed checks

to be

made before

the

utility turns

on the

power

are as

follows:

76.

Cable

and

circuit

are

identified

per

contract specification requirements.

77.

Switchgear

key

interlock scheme prevents paralleling feeders

(if

there

is

more than

one

feeder).

78.

Switchgear door interlock

functions

are

a.

Door cannot

be

opened with switchgear closed.

b.

Switch cannot

be

closed

with door open.

c.

Access

to all

power

fuses

is

possible

only when switches

are

open.

79. All

switchgear secondary

and

low-voltage compartments

are

isolated

by

barriers

from

high-voltage com-

partments.

80.

Switchgear current-limiting

fuses

are

rated

in

accordance with

the

contract documents.

81.

Switchgear safety-glass window makes disconnect blade visible. Stored-energy disconnect switch mecha-

nism

operates.

82.

Switchgear

weatherproofing

(if

outdoor type), ventilation, thermostat,

and

heaters

are

operational.

83.

Switchgear protective relay settings

are in

accordance with manufacturers' recommendations

and

coordina-

tion/short-circuit protection limits. Each incoming line

has

time-delay

overcurrent

and one

time-delay

ground

fault

protective relay.

84.

Pomeads

or

other

cones

on all

power

cables

are

installed properly.

85.

Nameplates, warning,

and

"danger—high

voltage"

signs

are

installed.

86.

Perform high potential (voltage) tests

at

switchgear

for 1 min on

primary

and

secondary circuits. Factory

test reports

on

high potential tests

are

acceptable.

87.

Switchgear schematic control diagrams

are

correct.

88. See

that transformer nameplate data, high-voltage warning signs,

and

high-

and

low-voltage compartment

isolation

are in

place.

89.

Transformer door interlocks: assure

a.

Low-voltage compartment door

can be

opened

first.

b.

High-voltage compartment door cannot

be

opened

first.

90.

Transformer high-voltage compartment switch

fuse

is

operational.

91.

Transformer

low-voltage

compartment

has

a.

No-load

tap

changer.

b.

Liquid-level gauge

on

liquid-fill transformer.

c.

Dial thermometer.

d.

Level

and

temperature alarm contact.

e.

Ground

pad and

proper grounding.

Motor

Control

Centers (MCC)

92.

Control centers

are

NEMA class

as

specified.

93. Bus

rating conforms

to

specifications.

94. The

circuit breaker

is

sized properly,

of the

proper type,

and is

adjusted

as

specified.

95.

Motor starters

are

sized properly

and

provided with proper thermal overload relays with heaters

on

each

leg as

specified.

96.

Wiring

and

conduit

from

the

control

to the

motor

is

sized

per

NEMA standards

as a

minimum.

97.

Automatic

and

manual switches

are

furnished

and

operational

as

specified.

98. If

combination motor-circuit

protectors

and

magnetic starters

are

furnished,

determine that

the

motor-cir-

cuit

protectors

are

sized

in

accordance with manufacturer's recommendations.

Adjust

the

current limiters

properly.

99.

Feeder circuit breakers

are

installed, sized,

and

adjusted

as

specified.

100. Main

and tie

circuit interrupters

are

rated

as

specified

and

capable

of

carrying

full-rated

current

to

feed

the

breakers

as

specified.

101. Current

and

potential transformers

are

sized

and

electrically connected

as

specified.

102.

All

control switches

are

furnished

and

operating

as

required.

103. Relay panels

are

furnished

with subpanels, control relays, timing relays, repeat cycle timers, protective

relays,

phase-failure relays, timers,

and

latching relays

and are

adjusted

as

required. Terminal block wiring

and

all

necessary appurtenances

are

complete.

104. Fuse blocks

are

furnished

and

sized properly.

105.

Elapsed-time

meters

are

furnished

and can be

adjusted

as

specified.

106. Remote control

(stop-start)

devices

are

installed

at the

equipment

and are

properly connected

to the

MCC.

107. Manual motor starters

are

furnished

for the

low-voltage, low-horsepower, single-phase equipment

and

have

proper current protection.

108. Line disconnect devices

or

circuit breakers

are

furnished

for

manual starters.

109.

The

spare parts

for

switchgear

and MCC are

supplied

as

specified.

Switchgear

Operations

for Two

Independent

Power

Lines

(If

Furnished)

110. Coordinate energizing

of

switchgear with client personnel, power company,

and

contractor. Arrange

for

power outage testing

as

required.

111. Coordinate switchgear automatic transfer control voltage

and

time-delay relay settings with power com-

pany.

Review power company recommended settings with client personnel

and

make setting adjustments

as

directed

by the

client.

Energizing

the

Station

112. Now, stand

as far

back

as

possible

and

have

the

utility turn

on the

power.

In any

event, make sure that

nobody

is

standing

in

front

of any

electrical

equipment when

it is

energized

for the first

time

or, for

that

matter,

reenergized

at any

time.

113. Close

the

main circuit breaker

or

fusable

switch. This will

be the first

time that

the

switchboard

bus is

energized since

the

high-pot test (on-site

or at the

factory).

Never stand

in

front

of a

circuit breaker

or

switch

when operating

it.

114. Test

for

correct voltage range.

Do not use a

multimeter

for

this purpose.

Do use a

solenoid tester with

fused

leads (such

as

manufactured

by

Ideal

or

Square

D).

Once

the

presence

of the

correct voltage range

has

been established, exact voltage

can be

measured with

a

multimeter. Utilities typically

are

required

to

set

voltages within

±10%

of

nominal.

At the

no-load condition,

the

voltage

for a

480-V

system should

be

between

480 and 506 V.

115. Test

for

correct phase sequence. Most engineers

specify

phase sequence

as

left

to right

when viewed

from

the

front

and

front

to

back

on

switchboards.

At

this point, testing

may

diverge into

two

separate paths.

The

contractor

is

likely

to

want

to

start

"bumping"

motors

because

it is

easy. However,

it is

preferable

to

start testing

the

control system. Because overload heaters

and

fuses

have been removed

from

the

starters,

a

complete functional test

can be run on the

control system with-

out

endangering mechanical equipment.

116. Check calibration

of all

instrumentation equipment. Instrumentation

may

well

have

been calibrated before

it

left

the

factory,

but

since then

it has

suffered

vibration

and

shock

from

transportation

and

dampness

from

sitting

in a

nonenergized state

for

several months.

117. Test manual control devices. Operate start, stop, jog, etc. devices

to

determine whether

the

contactors

and

circuit

breakers respond correctly.

118. Test

safety

devices. Close power devices manually

and

manually actuate

the

safety

device

to

determine

if

the

power device trips.

119. Test automatic control systems

by

placing

all

equipment

in the

automatic mode

and

simulating

operation

of

the

various control devices

to

determine whether

the

power devices

function

correctly. Simulation

of

control device operation should

be

accomplished

as

close

to the

process

as

possible.

For

example,

it is

bet-

ter

to

apply

a

pressure signal

to

transmitter process input with

a

pneumatic test

set

than

to

simulate

the

pressure transmitter output with

an

electronic test set.

As

another example,

it is

better

to

move

a

valve

manually

to

test limit switches than simply

to

move

the

limit switch

arm by

hand.

At

this point, much

of the

power system will have been energized

in a

no-load state

for

several days. Insula-

tion failures that

are

likely

to

occur will probably have occurred with

a

minimum

of

inconvenience

to the

start-

up

process.

It is

time

to

start energizing power equipment.

120. Check actual motor nameplates against motor starter application data

and

install correct motor overload

heaters. Follow

the

same procedure

for

power

fuses

on

high-voltage motor starters.

121. Rack

in

high-voltage starters

and

circuit breakers

to the

operating position.

122. Bump motors.

Before

bumping

any

motor,

verify

that reverse rotation will

not

damage mechanical equip-

ment.

If

mechanical equipment

can be

damaged

by

reverse rotation, open coupling

or

remove drive

belts

as

applicable.

Tests

of the

electrical

and

control systems have

now

been taken

as far as

practical without actual operation.

In

wastewater pumping stations particularly,

it is

certainly prudent

to

test

the

entire station with clean water

before

filling

the

station with sewage,

but if the

electrical designer

has

done

his job and the

start-up engineer

has

performed

the

above steps,

the

station electrical system should

be in

reasonably good condition. Once

the

sta-

tion

is

actually started,

it

will

be

necessary

to

adjust

the

control system

for

stable operation under dynamic con-

ditions.

The

time delay cannot

be set

until

the

station

is

operating normally.

Energizing

a

Station with

Two

Independent Power

Sources

123. Energize both power company lines

and

transformers. Establish normal switchgear operation

with

two

nonparalleling sources.

124.

See

that

switchgear metering operates properly

and

that

the

meter registers accurately

with

reference

to

known

existing loads.

125.

Test

automatic

transfer

operation with controller

in

live test mode. Simulate loss

of

power

at one

power line

by

pushing

and

holding

loss-of-voltage

test pushbutton. Note indicator lights that indicate opening

of

line

switch

followed

by

closing

of tie

switch. Note timing

of

both switch indicator lights. Note that switches

do

not

actually operate

in

this test. Note annunciator alarms

at MCC or

control panel

(if any are

furnished).

126. Simulate return

of

power

by

release

of

test button. Note that

tie

switch light indicates opening condition

followed

by the

line switch light indicating closed

position.

Note that switches actually

do not

operate.

Acknowledge

and

reset

annunciator.

127. Repeat

the

above test

on the

other power company line

and

note

the

results.

128. With switchgear returned

to

normal, place automatic transfer control switch

on

automatic position. Simu-

late loss

of

voltage

on one

phase

of

power company line

by

other than

the

test pushbutton. Note time

to

actual

opening

of the

line switch followed

by

closing

of tie

switch. Note annunciator alarms.

129. Simulate loss

of

second power company line. Note that

no

switch position changes take

place.

130.

Simulate return

of

power

to

power company

first

line.

131.

Note time

to

open power company second-line switch, followed

by

time

to

close

first-line

switch. Note

that

the tie

switch remains closed.

132.

Simulate return

of

power

to

power company second line. Note particularly

the

time between opening

of

the tie

switch

and

closing

of the

second power company

line

switch. Reset annunciator alarm.

133.

Repeat

the

above test

by

simulating simultaneous loss

of

both power company lines. Note that

no

switch

transfer

takes place. Return

the

system

to

normal.

134. Simulate phase

and

ground

overcurrent

on

each power company

line

by

protective relay action. Note

opening

of

affected

line switch. Note automatic transfer control lockout,

tie

switch remaining open,

and

annunciator alarm.

135.

Reset

the

lockout

at the

switchgear, place

the

selector switch

on

manual position,

and

close

the tie

switch.

136.

Place

the

automatic transformer control switch

in

manual position

and

repeat simulated loss

and

return

of

power. Note that

the

switches respond only

to

manual controls.

137.

Return

the

switchgear control

and

plant equipment

to

normal.

Automatic

Transfer

Switch

(If

Furnished)

138.

Note that

the

automatic

transfer

scheme

of the

motor control center

is

similar

to the

switchgear automatic

transfer

scheme. Differences include

the use of

circuit breakers instead

of

high-voltage

disconnect

for

voltage

transfer,

and

utilization

of

control time setting longer than

the

switchgear setting. Transfer

and

return

time delay should

be set

approximately

2

seconds longer than

the

switchgear setting

to

avoid out-

of-phase

transfer

and

damage

to

equipment.

139.

MCC

automatic transfer test setting (automatic mode)

can

therefore

be

coordinated with

the

switchgear

testing

and

with testing

of

standby generator.

140.

Be

sure

MCC

incoming voltage

and

control voltage

are

within acceptable limits

for

both primary

and

alternate power sources.

141. Indicating lights

are

operational

for

motor

off

or

running, valves open

or

closed,

power

on,

ready,

and

trip.

142. Control relays

and

timers

are

properly sized

and

adjusted

as

specified.

143. Alternators

are

operational.

144.

All

indicating voltage, current,

and

power devices

are

registering properly.

H-4. Simplified Operational

Checks

for

Small

Stations

First read Items

71

through

144 and 187

through

336.

Follow

any

procedures that apply. Make

the

following

tests

for

each main pump.

145. Start

the

main pump with

the

discharge isolation valve closed

and the

discharge pressure gauge valve

closed. Read ampere draw.

146. Slowly open

the

discharge valve

and

slowly

fill the

transmission pipe

or

force main. Bleed

any

entrapped

air.

147. When pipe

is

full,

open discharge isolation valve wide open. Open valve

to

pressure gauge

and

bleed

air.

148. Compare discharge pressure head

and flowrate

with design operating point. Read ampere draw

and

com-

pare with calculated wattage.

If

necessary, trim impellers

to

make pump operate within,

for

example,

±10%ofbep.

149. Repeat

the

above steps

for

other pumps.

150.

Run

through cycles

and

observe level controls, operation

of

pump sequencer, pressure,

and flowrate for

all

combinations

of

pumps operating. (Can

be

accomplished

by

introducing false signals

into

the

control

system.)

151.

Be

alert

to any

undue

noise,

vibration,

or

other operational problems.

H-5.

Well

Pumps

Pumping

from

a

well

is

usually done with

a

multistage, vertical turbine pump, either

of the

lineshaft

or the

sub-

mersible type.

The

pump setting (the distance

from

the

pump suction

to the

well head) can, depending

on the

water

table, vary

from

a few

feet

to

several hundred

feet.

Although lineshaft

and

submersible units each have

distinct

features

and

advantages, lineshaft pumps

are

typically used

for

shorter settings,

and

submersible pumps

are

often

preferred

for

settings greater than

500 to 700 ft.

Lineshaft pumps with substantially

deeper

settings

are

used

where electric power

is not

available.

Before

installing

any

well pump,

the

following should

be

checked:

152.

The

well casing must

be

reasonably straight, preferably within

25 mm per

3Om(I

in. per 100 ft)

depth

and

without double bends

to

avoid binding

the

equipment. Straightness

may be

checked with

a

dummy

assembly,

slightly longer

and

larger

in

diameter than

the

actual pump, lowered

on a

cable down

the

well

to

the

actual pump setting.

153.

New

wells should

be

checked

for the

release

of

excessive amounts

of

sand

for the first few

days

after

start-

up.

Because sand

is

harmful

to

close-running clearances within

the

pump, wells suspected

of

being sandy

should

first be

"developed"

by a

pump other than

the

production unit.

154. Make sure

the

perforated section

of the

well casing

is

well below

the

operating water level

to

avoid cas-

cading

and air

entrainment (that causes reduced pump output).

For the

same reason, return lines should

not

be

connected

at the top of the

well casing.

155. With

the

pump installed

and

operating, check

the

"drawdown"

with

an air

line

down

the

well

to

make sure

the

pump still

has

adequate

NPSH

A

.

("Drawdown"

is the

amount

the

water level drops

in the

well

from

static condition

to

full

operating

flow.)

Submersible

Well

Pumps

Submersible pumps

are

directly connected

and

driven

by a

submersible

electric

motor.

Two

types

of

motors

are

used:

wet

winding

and dry

winding.

In wet

winding motors, well water

is

permitted

to

enter

the

motor

and

sur-

round

the

heavily insulated stator winding,

or the

motor

is filled

with

a

clean, aqueous solution.

The dry

winding

motor

is

either

sealed

and

completely

filled

with oil,

or

only

the

stator winding

is

sealed

off

from

the

well water.

Because

the

pump

and

motor

are

close-coupled

on

submersible units,

shaft

critical speed

is

typically

not a

concern.

The

unit

can

therefore

be

operated

at the

optimum rotational speed.

In

addition

to the

general precautions

and

checks above, make sure

of the

following:

156.

The

motor

shaft

sealing device varies

significantly

from

manufacturer

to

manufacturer,

so

make sure

the

proper

prestart

instructions

are

followed.

157. Check

the

liquid level

if the

motor

is fluid filled, and

refill

as

required.

158.

If

pump

and

motor

are

shipped separately, make sure

the

shafts

are

aligned carefully when

the two

assem-

blies

are

connected.

159. When

the

power cable

is

shipped separately, make sure

a

watertight connection

is

made

at the

motor ter-

minal box.

160. Just before lowering

the

unit into

the

well, take

a

megger (ohm meter) reading

on the

motor-cable assem-

bly

to

ensure electrical integrity.

161. When

the

motor

is

submerged

to the

normal operating level, repeat

the

megger test

of the

motor-cable.

If

the

megger reading

is

below

the

minimum specified

by the

manufacturer,

the

cause must

be

found

and

cor-

rective measures taken before start-up.

162. Check

the

starting panel

to be

sure that

all

electrical

controls

and

instruments

are

functioning properly.

163. Check

the

unit

for

rotation

by

comparing

the

closed valve-head reading with

the

manufacturer's rating

curve.

Centrifugal pumps develop substantially lower head

at the

closed valve when

run in

reverse. Switch

two

of the

leads

in the

starting panel

if

necessary.

164. Repeat

the

megger reading

after

the

motor

has

reached operating temperature

and has

been running

for a

few

hours.

Lineshaft

Pumps

Lineshaft

pumps

are

most commonly driven

by a

vertical, hollow-shaft motor, which

is

mounted

on top of the

pump

discharge head

and

connected

to the

pump bowl assembly

by a

lineshaft housed within

the

discharge col-

umn.

A

drive clutch

at the top end of the

motor provides

for

substantial vertical

shaft

adjustment.

The

adjustment

is

important, because

the

hydraulic thrust developed

in the

pump must normally

be

carried

by the

thrust bearing

in

the

motor. Elastic elongation

of the

lineshaft occurs while

the

pump

is

operating,

and

this elongation

can be

substantial

for

deep setting pumps.

Lineshaft

pumps

can

also

be

driven

by a

vertical solid-shaft motor, connected

to the

pump lineshaft with

a

conventional, rigid coupling,

or the

pump

can be

driven

by a

horizontal gasoline, diesel,

or gas

engine connected

to a

hollow

shaft

through

a

right-angle

gear.

If

reverse rotation would cause equipment damage

(by

overspeed

or to

engine drives)

the

drivers

may be

fitted

with

a

nonreverse ratchet. However,

it

should

be

noted that when

a

pump spins

in

reverse

due to

backflow,

the

direction

of

torque

in the

shafting

is the

same

as for

normal operation,

so

pump damage

is

usually

not a

concern.

The

lineshaft runs

in

bearings housed within

the

discharge column. When clean water

is

pumped,

the

bear-

ings

are

lubricated

by the

pumped liquid.

The

bearings

are

usually

of

rubber

or

bronze material

and

housed

in

spiders

at

3-m

(10-ft)

centers. When water containing abrasive material

is

pumped,

the

lineshaft

is

located

within

an

enclosing tube,

and

externally threaded bronze bearings

are

used

to

connect

the

enclosing tube sec-

tions.

The

bearings

are

lubricated with

oil or

clean water injected into

the

enclosing tube

at the

discharge head.

Piping

and

valve arrangements

at the

well head

may

vary greatly depending

on the

application. Some typical

arrangements

of

piping

are

shown

in

Figures

7-9 to

7-11,

and

18-18.

In

addition

to the

general precautions recommended above, note

the

following points:

165. Before connecting

the

driver

to the

lineshaft, check

the

driver

for

correct rotation

as

indicated

by the

arrow

on

the

pump discharge head.

166.

See

that

the

discharge head

is

grouted properly

at the

well head

and

that

a

well seal

is

provided

if

required

by

local code.

167. Deep setting, open lineshaft pumps normally require

pre-lubrication

of the

lineshaft bearings. Make sure

the

proper connections

are

made

and the

pre-lube

system

is

functioning.

168.

For

pumps with

fresh

water

or oil

injection

to the

inner column,

see

that

the

lubrication reservoirs

are

filled,

the

proper piping connections

are

made,

and

electrically operated valves

are

functioning.

169.

See

that

all

pump discharge connections

are

made

and

pressure tested properly,

flexible

pipe

couplings

have

been correctly harnessed with tie-bars, pipe anchors

are in

place,

and no

undue pipe stress

is

being

imposed

on the

pump discharge head.

170. Check that

the air and

vacuum release valve

on the

pump discharge

is

connected

and

functioning correctly.

171. Make

a final

wiring

and

instrument check

at the

starting panel

and

include connections

for

electrically

operated control valves.

172. Check that

the

pump rotating element

has

been given

the

proper

lift

as

specified

by the

manufacturer. (The

vertical

adjustment

is

made

at the

driver coupling clutch.)

173. Follow

the

procedure outlined

in the

main pump section

for filling and

venting

the

discharge pipeline.

174. Start

the

unit

and

slowly open

the

discharge control valve.

Adjust

the

shaft

seal

at the

discharge head

as

required.

175. With

the

pump operating

at

design

flow,

check general mechanical functioning (e.g., noise, vibration).

176. Double check controls

and

alarms

for

functioning.

Make sure

the

manufacturer's minimum

flow

require-

ments

will

be

met.

177. Take pump head readings with

the

pump operating

at

design

flow and

also against

the

closed

valve,

and

compare with

the

manufacturer's performance curve. With good

field

instruments,

the

readings should

be

within

5% of the

factory test.

Pumping Station Desing - Second Edition by Robert L. Sanks, George Tchobahoglous, Garr M. Jones

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