Type MWTU 11Forward and Reverse Power Relay

2

Type MWTU 11Forward and Reverse Power Relay

ApplicationsThere are two versions of theMWTU 11 available; one for powermeasurement (W) and one forreactive power measurement (VAR).

The MWTU 11 is suitable for thefollowing applications:

Reverse power protection of agenerator against motoring

The relay has sensitive settings andoperates accurately for boundaryconditions up to ±87.1° (0.05power factor). The definite timecharacteristic ensures thatmaloperation does not occur due tomomentary power reversals duringsynchronising or power swings onthe system. Trip output connectionsshould be made to the set of time-delayed output contacts.

Figure 1: MWTU 11

Limitation of power importedfrom a consumer by a utilitypower supply

This application is an over power orforward power function in whichhigher settings are required.The directional discrimination is notrequired at such low power factorsfor reactive components as high as60% of the generator rating.The operating time of the relay isnot critical as fast tripping times arecovered by fault detecting relays.

Reverse VAR connections

The single phase VAR relay may beused with a quadrature connectionto measure reactive power.

Features• Wide power setting range

• Accuracy maintained at lowpower factors

• Non-volatile trip indication

• Measures forward and reversepower

• Instantaneous element

• Low burden

3

Figure 3: Instantaneous element disengaging times.

Figure 2: Instantaneous element operating times.

DescriptionThe MWTU 11 is a single phaserelay measuring I Cos φ, offering awide power setting range (from 1%to 32.5% of rated power.

A low quiescent current supply drainis achieved by use of a switch modepower supply. This allows the relayto work over a wide auxiliaryvoltage range and to be operatedfrom either ac or dc supplies. It alsogives 2kV isolation. A green LEDindicates that a supply is present onthe relay terminals.

The time delay starts from either theoperation or the reset of theinstantaneous element, allowing theMWTU 11 to be used for eitheroverpower or underpowerapplications. A non-volatile tripindication is given by a red LED anda reset push-button resets thebistable relay and trip indicator.

0 2 4 6 8 10 12 14 16 18 200

200

400

600

800

1,000

1,200

1,400

1,600

Time

(ms)

Current as multiple of Ps setting

Ps = 32.5%Ps = 16%Ps = 10%Ps = 5%Ps = 3%Ps = 1%

0 5 10 15 20 25 30 350

100

200

300

400

500

600

700

800

900

1,000

Time

(ms)

Ps setting (%Pn)

4

Figu

re 4

: Ty

pica

l app

licat

ion

diag

ram

– p

hase

to

phas

e re

vers

e po

wer

con

nect

ion.

L NV

AC

Not

es:

1.(a

)CT

shor

ting

links

mak

ebe

fore

(b) a

nd (c

) disc

onne

ct.(b

)Sh

ort t

ermi

nals

brea

k bef

ore

(c).

(c)

Long

term

inal

.(d

)Pi

n te

rmin

al (P

CB ty

pe).

2.CT

con

necti

ons a

re ty

pica

l onl

y.3.

VT c

onne

ction

s are

typi

cal o

nly.

4.Ea

rthin

g co

nnec

tions

(CTs

) are

typi

cal o

nly.

IN

Dire

ction

of p

ower

flow

for

insta

ntane

ous r

elay o

pera

tion

A B C

P2P1

S2S1

AB

C

ab

c27 28

(See

note

2)

21 22 23 25

(See

note

4)

(See

note

3)

9 10 13 14

Powe

rsu

pply

circu

its

VN

P S

V ref

f(a>b

)a b

RL1 2

tRL

2 2 RL3 1

Rese

tRese

t

Op

Trip

Powe

r

Phas

ese

nsitiv

ebr

idge

A

CB

Phas

e ro

tatio

n

20 17 19

RL2–

1

15 16

RL2–

2

6 2 4

RL1–

1

1 5

RL1–

2

Insta

ntane

ous

conta

cts

MW

TU 1

1

+VE

–VE

VX

8

Mod

ule

term

inal

blo

ckvi

ewed

from

rear

Case

ear

th

56

1314

1516

12 4

17 1920

2122

23 25 27288

910

Time-d

elaye

dco

ntacts

Case

ear

th co

nnec

tion

5

Figu

re 5

: Ty

pica

l app

licat

ion

– ph

ase

to n

eutr

al r

ever

se p

ower

con

nect

ion.

Not

es:

1.(a

)CT

shor

ting

links

mak

ebe

fore

(b) a

nd (c

) disc

onne

ct.(b

)Sh

ort t

ermi

nals

brea

k bef

ore

(c).

(c)

Long

term

inal

.(d

)Pi

n te

rmin

al (P

CB ty

pe).

2.CT

con

necti

ons a

re ty

pica

l onl

y.3.

VT c

onne

ction

s are

typi

cal o

nly.

4.Ea

rthin

g co

nnec

tions

(CTs

) are

typi

cal o

nly.

IN

Dire

ction

of p

ower

flow

for

insta

ntane

ous r

elay o

pera

tion

A B C

P2P1

S2S1

AN

27 28

(See

note

2)

21 22

(See

note

3)

VN

P S

V ref

f(a>b

)a b

RL1 2

tRL

2 2 RL3 1

Rese

tRese

t

Op

Trip

Phas

ese

nsitiv

ebr

idge

A

CB

Phas

e ro

tatio

n

MW

TU 1

1

an

N

23 25

L NV

AC

(See

note

4)

9 10 13 14

Powe

rsu

pply

circu

its

Powe

r

+VE

–VE

VX

8

Mod

ule

term

inal

blo

ckvi

ewed

from

rear

Case

ear

th

56

1314

1516

12 4

17 1920

2122

23 25 27288

910

20 17 19

RL2–

1

15 16

RL2–

2

6 2 4

RL1–

1

1 5

RL1–

2

Insta

ntane

ous

conta

cts

Time-d

elaye

dco

ntacts

Case

ear

th co

nnec

tion

6

Figu

re 6

: Ty

pica

l app

licat

ion

diag

ram

– p

hase

to

phas

e re

vers

e VA

r co

nnec

tion.

Not

es:

1.(a

)CT

shor

ting

links

mak

ebe

fore

(b) a

nd (c

) disc

onne

ct.(b

)Sh

ort t

ermi

nals

brea

k bef

ore

(c).

(c)

Long

term

inal

.(d

)Pi

n te

rmin

al (P

CB ty

pe).

2.CT

con

necti

ons a

re ty

pica

l onl

y.3.

VT c

onne

ction

s are

typi

cal o

nly.

4.Ea

rthin

g co

nnec

tions

(CTs

) are

typi

cal o

nly.

IN

Dire

ction

of p

ower

flow

for

insta

ntane

ous r

elay o

pera

tion

A B C

P2P1

S2S1

BC

27 28

(See

note

2)

21 22

(See

note

3)

VN

P S

V ref

f(a>b

)a b

RL1 2

tRL

2 2 RL3 1

Rese

tRese

t

Op

Trip

Phas

ese

nsitiv

ebr

idge

A

CB

Phas

e ro

tatio

n

MW

TU 1

1

bc

L NV

AC

9 10 13 14

Powe

rsu

pply

circu

its

Powe

r

+VE

–VE

VX

8

Mod

ule

term

inal

blo

ckvi

ewed

from

rear

Case

ear

th

56

1314

1516

12 4

17 1920

2122

23 25 27288

910

20 17 19

RL2–

1

15 16

RL2–

2

6 2 4

RL1–

1

1 5

RL1–

2

Insta

ntane

ous

conta

cts

Time-d

elaye

dco

ntacts

(See

note

4)

Case

ear

th co

nnec

tion

7

Technical Data

Ratings

AC current (In) 1A or 5A

AC voltage (Vn)

Operative range 70% to 120%Vn

Power relay Rating Operative range (V)

Phase to neutral 57.7/63.5 40.4 – 76.269.3 48.5 – 83.2220/240 154 – 288

Phase to phase 100/110 70 – 132120 84 – 144380/415 266 – 498

VAR relay phase to phase 110 77 – 132120 84 – 144

Auxiliary voltage Nominal Operative range (V)(Vx) dc ac24/54 19 – 72 19.2 – 28.848/125 37 – 150 38.4 – 83.2110/250 87 – 300 80 – 144

Frequency 50/60Hz

Characteristics

Characteristic quantity I Cos φ

Relay characteristic angle 0°

Burdens

AC voltage burden Less than 1VA per phase

AC current burden Less than 0.1VA for 1A relays andless than 0.2VA for 5A rated relaysat unity power factor and at ratedcurrent on any setting.

DC supply burden Maximum burdens over fulloperative range.

Voltage Quiescent Both outputrating (W) relays(Vx1) operated

(W)24/54 1.5 548/125 1.5 6110/250 2.5 6

AC supply burden Maximum burdens over fulloperative range.

Voltage Quiescent Both outputrating (VA) relays(Vx2) operated

(VA)24 1.5 5.548/69.3 2.5 6.5100/120 3.5 8

8

Setting ranges

Power setting 1% to 32.5% Pn in 0.5% Pn steps

Time delay 0.25s to 32s in 0.25s steps

The time delay may be set to startfrom the operation or reset of theinstantaneous element.

Operating time characteristics

Instantaneous operate time 7.4at RCA VnIs(I – 1) ms

where Is =PsVn

and I = multiples of Is

See Figure 2

Instantaneous resetting anddisengaging times at RCA The disengaging time at RCA, as

the current is switched off, dependson the power setting Ps and isshown in Figure 3.

Time delayed reset anddisengaging times at RCA Less than 10ms from when the

instantaneous output elementoperates or resets as applicable.

Reference conditions for accuracy claims

Power setting (Ps) 16% Pn

Voltage 100% Vn(For relays covering more than onenominal voltage range the referencecondition is the highest nominalvoltage).

Time delay 4s

Ambient temperature 20°C

Frequency 50Hz or 60Hz

DC auxiliary voltage Rating Reference

24/54V 24V48/125V 48V110/250V 110V

AC auxiliary voltage 24V 24V48/69.3V 48V100/120V 100V

9

Accuracy under reference conditions

I Cos φ at RCA Over the operative range of Ps to20Ps subject to a maximum currentof 2In.

±3% of the setting ±2mA(for In = 1A) or ±10mA (for In 5A)whichever is the greater.

Boundary of operation φ = ±1.5° at system angles between±80° and ±87.1°

φ = ±5°or ±5% I Cos φ(whichever is the greater) at systemangles between ± 80° from RCA

Note: The boundary of operationwill not exceed ±90°from RCA.

Instantaneous operating time ±10% or 15ms whichever is thegreater, over the operative range of2Is to 2In

where Is =PsVn

and I = multiples of Is

Operating time ±5% or 50ms whichever is thegreater.

Repeatability better than 1%

Setting time better than 1%

Resetting value The relay will reset when the powerin the operating direction is lessthan 97% Ps.

Directional stability The relay will remain stable for 20times In in the restrain direction 20times In with Vn = 0V

Accuracy variation with influencing conditions

Ambient temperature

Operative range –25°C to +55°C

I Cos φ at RCA Less than 0.05%/°C

Accuracy of boundaryof operation φ = ±1° at system angles between

±80° and ±87.1°

φ = ±3° at system angles between±80° from RCA

Variation in operating time Less than 0.1%/°C

10

Frequency

Operative range 47 – 52Hz or 57 – 62Hz

I Cos φ at RCA ±1%

Accuracy of boundaryof operation φ = ±1% at system angles between

±80° and ±87.1°

φ = ±3° at system angles between±80° from RCA

Variation in operating time ±1%

I Cos φ at RCA ±2%

Contacts

Instantaneous 1 changeover and 1 normally open

Time delayed 1 changeover and 1 normally open

Make and carry for 0.2s 7500VA subject to a maxima of30A and 300V ac or dc

Carry continuously 5A ac or dc

Break ac 1250VAdc 50W resistive

25W L/R = 40mssubject to maxima of 5Aand 300V

Durability

Loaded contact 10,000 operations minimum

Unloaded contact 100,000 operations minimum

Current transformer requirements

IEC 60185 In = 1A 5VA class 1; maximum leadresistance 1.5Ω

In = 5A 10VA class 1; maximumlead resistance 0.3Ω

Voltage transformer requirements

IEC 60186 15VA class 1

See Figures 4, 5 and 6 for typicalapplication diagrams

11

Thermal withstand

Continuous withstand

Current 2 times rated value

Voltage 1.2 times rated value

Short time withstand

Current For 1s 100In with 400A maximum

For 3s 57In with 230A maximum

Operation indicators A green LED is used to indicate voltsare present on the relay and theinternal dc/dc converter isoperating.

The operation of the time delayedelement operates a red LED tripindicator. A latching relay is used toremember the state of the tripindicator, thus ensuring that the tripstate is not lost if the power to therelay fails. The reset push button onthe front plate resets the tripindicator.

High voltage withstand

Dielectric withstandIEC 60255-5: 1997 2kV rms for 1 minute between all

terminals and case earth.

2kV rms for 1 minute between allterminals of independent circuits,with terminals on each independentcircuit connected together.

1kV rms for 1 minute acrossnormally open contacts.

High voltage impulseIEC 60255-5: 1977 Three positive and three negative

impulses of 5kV peak, 1.2/50µs,0.5J between all terminals andearth.

12

Electrical environment

High frequency disturbanceIEC 60255-22-1: 1988 Class III 2.5kV peak between independent

circuits and case.

1.0kV peak across terminals of thesame circuit.

Fast transient disturbanceIEC 60255-22-4: 1992 Class IV 4kV, 2.5kHz applied directly to

auxiliary supply.IEC 60801-4: 1988 Level 4 4kV, 2.5kHz applied directly to all

inputs.

Surge immunityIEC 61000-4-5: 1995 Level 3 2kV peak, 1.2/50µs between all

groups and case earth.

2kV peak, 1.2/50µs betweenterminals of each group.

DC supply interruptionIEC 60255-11: 1979 The unit will withstand a 10ms

interruption in the auxiliary supply.under normal operating conditions,without de-energising.

AC ripple on dc supplyIEC 60255-11: 1979 The unit will withstand 12% ac

ripple on the dc supply.

AC voltage dipsIEC 61000-4-11: 1994 The unit will withstand dips of

100%, 60% and 30% Vx each of1.0s, 0.5s and 20ms duration.

AC voltage variationsIEC 61000-4-11: 1994 The unit will withstand voltage

reductions to 40% Vx and 0% Vxwith 2s ramp down, 1s at reducedvoltage, 2s ramp up times.

EMC compliance89/336/EEC Compliance to the European

Commission Directive on EMC isclaimed via the TechnicalConstruction File route.

EN 5008-2: 1994 Generic Standards were used toEN 5008-2: 1995 establish conformity.

Product safety73/23/EEC Compliance with the European

Commission Low Voltage Directive.

EN 61010-1: 1993/A2: 1995 Compliance is demonstrated byEN 60950: 1992/A11: 1997 reference to generic safety

standards.

13

Atmospheric environment

TemperatureIEC 60255-6: 1988 Storage and transit –25°C to +70°C

Operating –25°C to +55°C

IEC 60068-2-1: 1990 Cold

IEC 60068-2-2: 1974 Dry heat

HumidityIEC 60068-2-3: 1969 56 days at 93% RH and +40°C

Enclosure protectionIEC 60529: 1989 IP50 (dust protected)

Mechanical environment

VibrationIEC 60255-21-1: 1988 Response Class 2

SeismicIEC 60255-21-3: 1993 Severity Class 2

14

Figure 7: Case outline size 4

CasesType MWTU11 relays are housedin size 4 cases, see Figure 7

97

177

Push buttonprojection 10 max.

32 21225 min.

157 max.

11103

99

52

23.54 holes Ø 4.4

168 159

Panel cut-out:Flush mounting fixing details.

All dimensions in mm.

Flush mounting.

Reset

15

Information requiredwith orderVAR or power relay

Auxiliary voltage rating (Vx)

Phase to neutral voltage rating (Vn)

CT rating

St Leonards Works, Stafford, ST17 4LX EnglandTel: 44 (0) 1785 223251 Fax: 44 (0) 1785 212232 Email: enquiries@pcs.alstom.co.uk Internet: www.gecalsthomgpc.co.uk

©1998 ALSTOM T&D Protection & Control Ltd

Our policy is one of continuous development. Accordingly the design of our products may change at any time. Whilst every effort is made to produce up to date literature, this brochure shouldonly be regarded as a guide and is intended for information purposes only. Its contents do not constitute an offer for sale or advice on the application of any product referred to in it.

ALSTOM T&D Protection & Control Ltd cannot be held responsible for any reliance on any decisions taken on its contents without specific advice.

Publication R6127C 019910 CPS Printed in England.

ALSTOM T&D Protection & Control Ltd