Low Voltage Selectivity QT1_EN

8/14/2019 Low Voltage Selectivity QT1_EN

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1SDC007100G0204

Technical Application PapersMay 2008

1

Low voltage selectivitywith ABB circuit-breakers


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1

IndexA theoretical outline o

selectivity

Introduction ............................................................. 2

Main denitionsSelectivity ................................................................ 3

Total selectivity - Partial selectivity .......................... 3

Overload zone Short-circuit zone ......................... 4

Real currents circulating in the circuit-breakers ...... 5

Selectivity techniquesTime-current selectivity ........................................... 7

Current selectivity .................................................... 8

Time selectivity ........................................................ 9

Energy selectivity ................................................... 10

Zone selectivity ..................................................... 11

How to obtain selectivity with

ABB circuit-breakers

Types o ABB circuit-breakers ............................... 12

MCB Miniature Circuit-BreakersSupply-side S200 / Load-side S200 ..................... 13

Supply-side S290D-S800D / Load-side S200 ...... 13

MCCB-MCB SelectivitySupply-side T1-T2-T3-T4 / Load-side MCB ......... 14

Supply-side T5-T6-T7 / Load-side MCB ............... 15

Low voltage selectivity with ABB circuit-breakers

Technical Application Papers

MCCB-MCCB SelectivityCurrent selectivity .................................................. 16

Time selectivity ...................................................... 17

Energy selectivity ................................................... 18

Zone selectivity (T4L-T5L-T6L) .............................. 19

ACB-MCCB SelectivityTraditional solution ................................................ 25

Zone selectivity between Emax and Tmax ............ 26

ACB-ACB SelectivityTime selectivity ...................................................... 28

Zone selectivity between Emax ............................. 29

Directional time selectivity ..................................... 32

Directional zone selectivity .................................... 34

Appendix A:

MV/LV selectivity ................................................... 40

Appendix B:

General considerations regarding residual currentselectivity ............................................................... 43

Appendix C:

Example o LV/LV selectivity study ........................ 45

Appendix D:

Further considerations regarding the real currents

circulating in the circuit-breakers .......................... 48

Glossary ............................................................... 52


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2 Low voltage selectivity with ABB circuit-breakers


A theoretical outline o selectivity

Problems and requirements or thecoordination o the protections

Selection o the protection system o the electrical instal-

lation is undamental both to guarantee correct economi-

cal and unctional service o the whole installation and

to reduce the problems caused by abnormal service

conditions or actual aults to a minimum.

Within the sphere o this analysis, the coordination be-

tween the various devices dedicated to protection o

sections o installation or specic components is studied

in order to:

guarantee saety o the installation and o people in allcases;

rapidly identiy and exclude just the area involved in

the problem, without indiscriminate trips which reduce

the availability o energy in areas not involved in the

ault;

reduce the eects o the ault on other integral parts

o the installation (reduction in the voltage value, and

loss o stability in rotating machines); reduce the stress on components and damage to the

area involved;

guarantee service continuity with good quality power

supply voltage;

guarantee adequate support in the case o malunction

o the protection delegated to opening;

provide the personnel in charge o maintenance andthe management system with the inormation needed

to restore service to the rest o the network as rapidly

as possible and with the least intererence;

achieve a good compromise between reliability, sim-

plicity and cost-eectiveness.

In detail, a good protection system must be able to: perceive what has happened and where, discriminating

between abnormal but tolerable situations and ault

situations within its zone o competence, avoiding

unwanted trips which cause unjustied stoppage o a

sound part o the installation; act as rapidly as possible to limit the damage (destruc-

tion, accelerated ageing, etc.), saeguarding powersupply continuity and stability.

The solutions come rom a compromise between these

two antithetic requirements precise identication o the

ault and rapid tripping - and are dened according to

which requirement is privileged.

For example, in the case where it is more important toprevent unwanted trips, an indirect protection system is

generally preerred, based on interlocks and data trans-

mission between dierent devices which locally measure

the electrical values, whereas speeds and limitation o

the destructive eects o the short-circuit require direct

action systems with with protection releases integrateddirectly in the devices. In low voltage systems or primary

and secondary distribution, the latter solution is normally

preerred.

With regard to the Italian Standard CEI 64-8 Electrical

user installations with rated voltage below 1000 V in alter-

nating current and 1500 V in direct current regarding lowvoltage installations, under Part 5 Selection and installa-

tion o the electrical components this states that:

Selectivity between protection devices against

overcurrents (536.1)

When several protection devices are placed in series and

when the service needs justiy it, their operating charac-teristics must be selected so as to disconnect only the

part o the installation where the ault is.

Moreover, in the comments, the ollowing is added:

The operating situations which require selectivity are

dened by the customer or by the designer o the in-

stallation.

The Standard thereore states that the operating charac-

teristics must be selected so as to have selectivity, when

the service needs justiy this.

In general, designing a selective installation not only

means realising a state-o-the-art project, but also

designing a good installation which does, in act, respondto the customers requirements, not simply to the aspects

o the Standards.


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3Low voltage selectivity with ABB circuit-breakers

Atheoreticaloutlineof

selectivity

Main denitions

SelectivityThe denition o selectivity is given by the IEC 60947-1

Standard Low voltage equipment - Part 1: General rules

or low voltage equipmentTrip selectivity (or overcurrent) (441-17-15)

Coordination between the operating characteristics o

two or more overcurrent protection devices, so that when

an overcurrent within established limits occurs, the device

destined to operate within those limits trips whereas the

others do not trip

where by overcurrent a current o a higher value than therated current is intended, due to any cause (overload,

short-circuit, etc.).

There is thereore selectivity between two circuit-break-

ers in series when, or an overcurrent which passes

through both, the load-side circuit-breaker opens thereby

protecting the circuit, whereas the supply-side one re-mains closed guaranteeing power supply to the rest o

the installation.

The denitions o total selectivity and partial selectiv-

ity are, on the other hand, given in Part 2 o the same

Standard IEC 60947-2 Low voltage Equipment - Part2: Circuit-breakers

Total selectivity (2.17.2)Overcurrent selectivity where, in the presence o two

protection devices against overcurrent in series, the load-

side protection device carries out the protection without

making the other device trip.Partial selectivity (2.17.3)

Overcurrent selectivity where, in the presence o two

protection devices against overcurrent in series, theload-side protection device carries out the protection

up to a given level o overcurrent, without making the

other device trip.

One can speak o total selectivity when there is selectiv-

ity or any overcurrent value possible in the installation.

Between a pair o circuit-breakers, one speaks o totalselectivity when there is selectivity up to the lesser o the

Icu values o the two circuit-breakers, since the maximum

prospective short-circuit current o the installation will inany case be less or equal to the smallest o the Icu values

o the two circuit-breakers.

One talks about partial selectivity when there is onlyselectivity up to a certain Is current value (ultimate

selectivity value). I the current exceeds this value, se-

lectivity between the two circuit-breakers will no longer

be guaranteed.

Between a pair o circuit-breakers, one speaks about

partial selectivity when there is selectivity up to a certain

Is value below the Icu values o the two circuit-break-

ers. I the maximum prospective short-circuit current othe installation is lower than or equal to the Is selectivity

value, one can still speak o total selectivity.

ExampleThe ollowing two circuit-breakers are considered:

On the supply side T4N250 PR221 In250 (Icu=36kA)

On the load side S294 C 100 (Icu=15kA)

From the Coordination Tables publication it can be seen that there

is total selectivity (T) between the two circuit-breakers.

This means that there is selectivity up to 15kA, i.e. the

lower o the two Icu values.

Obviously, the maximum possible short-circuit current at the pointo installation o the S294 C 100 circuit-breaker will be less than

or equal to 15kA.

Now the ollowing two circuit-breakers are considered:

On the supply side T4N250 PR221 In160 (Icu=36kA)

On the load side S294 C 100 (Icu=15kA)

ELTM, M

Supplyside

Version

Release

Iu [A]

In [A]

80

100

125

80100

5

5*

5

250

160 200 250 320

320 250 320

160 250 320

11

8

8*

118

T

T

12

T

T

T

T

TT

T

12

T12

T

T

T

TT

T

T

T

TT

T

N,S H,L,V

T4

Icu [kA]

15

Charact.

C-K

C

D

Load-side

S290

* Value valid with magnetic only circuit-breaker on the suppy side

T4N 250 PR221DS-LS/I

S 294 C 100

Tmax T4 - S290 @ 400/415 V

From the Coordination Tables publication it can be seen that the

selectivity value is Is=12kA between the two circuit-breakers.

This means that, i the maximum prospective short-circuit currenton the load-side o the S294 C 100 circuit-breaker is less than 12kA,

there will be total selectivity, whereas i the short-circuit current has

a higher value, there will be partial selectivity, i.e. only or the aults

with a current below 12kA, whereas or aults between 12 and 15 kAnon-tripping o the supply-side circuit-breaker is not guaranteed.


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selectivity

Overload zone Short-circuit zone By short-circuit zone one means the ranges o currentvalues, and thereore the relative part o the trip curveso the circuit-breaker, which are 8-10 times higher than

the rated current o the circuit-breaker.

This is the zone in which the magnetic protection or

thermomagnetic releases or protections S, D and I or

electronic releases are normally called on to intervene.

These current values usually correspond to a ault on the

supply circuit. This event is most unlikely than a simpleoverload.

For the purposes o the selectivity analysis made in this

publication, the concepts o overload zone and short-

circuit zone are introduced.

By overload zone one means the ranges o current

values, and thereore the relative part o the circuit-

breaker trip curves coming between the rated current o

the circuit-breaker itsel and 8-10 times this value.

This is the zone in which the thermal protection or

thermomagnetic releases and protection L or electronic

releases are normally called on to intervene.

These currents usually correspond to a circuit where a

load results to be overloaded. This event is likely to occur

more requently than a real ault.

0.1kA 1kA 10kA

104s

103s

102s

10s

1s

10-1s

10-2s

0.1kA 1kA 10kA

104s

103s

102s

10s

1s

10-1s

10-2s

Overload Zone = In 8-10In Short-circuit Zone => 8-10In

Main denitions


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tA

tB

IA IB

IB IA

tA

tB

IA=IB

tA

tB

IA=IB+Iloads

IA=(IB+Iloads)/n

IA=IB

A

B

A

B

A

B


selectivity

Real currents circulating in the circuit-breakers

When the time-current curves o two circuit-breakers are

compared, one is oten led to assess the trip times o

the two devices as i they were passed through by the

same current.This consideration is only true when, between the two

circuit-breakers placed in series, there are no other shun-

ts, i.e. there is a single incoming and a single outgoing

eeder which insist on the same node.

When, on the other hand, there are several supply-side

circuit-breakers which insist on the same busbar or

several outgoing eeders on the load side, the currents

which pass through the apparatus can be even consi-derably dierent.

With regard to the real currents circulating in the circuit-breakers, the three main cases which can be consideredare as ollows:- a single circuit-breaker on the supply side o a single

circuit-breaker on the load side (passed through by thesame current)

- a single circuit-breaker on the supply side o severalcircuit-breakers on the load side (supply-side circuit-breaker passed through by a current higher than thato the load-side circuit-breaker)

- two or more circuit-breakers on the supply side and

several circuit-breakers on the load side.

Where:IB

is the overcurrent which passes through circuit-breaker B

IA

is the overcurrent which passes through circuit-breaker A

Iloads

is the sum o the currents which, during normal operation, is consumed by the loads (excluding B) supplied by the supply-side

circuit-breaker A. This sum can, i necessary, be corrected with suitable contemporaneity and use actorsn is the number o circuit-breakers placed in parallel on the power supply side.

* These ormulas do not take into account the dierent phase displacement o the currents or any asymmetry o the circuit; the rst two ormulas are

however conservative and the third one is acceptable when the two supply circuits are equal.


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Time-current selectivityIn general, the protections against overload have a

denite time characteristic, whether they are made by

means o a thermal release or by means o unction L o

an electronic release.

A denite time characteristic is intended as a trip cha-

racteristic where, as the current increases, the trip time

o the circuit-breaker decreases.When there are protections with characteristics o this

type, the selectivity technique used is time-current se-lectivity.Time-current selectivity makes trip selectivity by adjusting

the protections so that the load-side protection, or all

possible overcurrent values, trips more rapidly than the

supply-side circuit-breaker.

When the trip times o the two circuit-breakers are analy-

sed, it is necessary to consider:

- the tolerances over the thresholds and trip times- the real currents circulating in the circuit-breakers.

Operatively speakingWith regard to the tolerances, ABB SACE makes the trip curves o their releases available in the technical catalogues and in the DOCWin

sotware. In particular, in the curve module o the DOCWin sotware, the curves o both the electronic and thermomagnetic releases include

the tolerances. A release trip is thereore shown by two curves, one which indicates the highest trip times (top curve), and the other whichindicates the most rapid trip times (bottom curve).For a correct analysis o selectivity, the worst conditions must be considered, i.e.:

- the supply-side circuit-breaker trips according to its own bottom curve

- the load-side circuit-breaker trips according to its own top curveWith regard to the real currents circulating in the circuit-breakers:

- i the two circuit-breakers are passed through by the same current, it is sucient or there to be no overlapping between the curve o

the supply-side circuit-breaker and the curve o the load-side circuit-breaker;

- i the two circuit-breakers are passed through by dierent currents, it is necessary to select a series o signicant points on the timecurrent curves and check that the trip times o the supply-side protection are always higher than the corresponding times o the load

side protection.

1.05 x I1 o the supply-side circuit-breaker

Assuming IA

=1.05xI1,with reerence to what has been said aboutthe realcurrents which circulatein the circuit-breakers, the I

Bcurrent

is obtained on the load side.

The trip times o the two devices are obtained rom the time-current

curves.

1.20XI3 (or I2)

o the load-side circuit-breaker

Assuming IB

= 1.20XI3 (or I2), the IA

current is obtained in the same

way on the supply side and, rom the time-current curves, the trip

times o the two devices are obtained.

I the ollowing is true or both the points considered:

tA>t

B

then selectivity in the overload zone is guaranteed.

1 1.05 is the value or minimum defnite non-intervention dictated by the Standard (IEC60947-2). For some types o circuit-breakers this value could vary

(see the technical catalogue or urther inormation).

2 1.2 is the value or maximum defnite intervention or protection against short-circuit dictated by the Standard (IEC60947-2). For some types o circuit-

breakers this value could be lower (see the technical catalogue or urther inormation).

A

B

In particular, in the case o circuit-breakers equipped with electronic releases, since the trend o the curves is at I2t=const, to carry out

the check correctly, it is sucient to examine two current values:1.05 x I11 o the supply-side circuit-breaker (value below which the supply-side protection never intervenes)

1.20XI3 (or I2)2 o the load-side circuit-breaker (value above which the load-side protection certainly trips with the protections against

short-circuit)Time-current Selectivity

0.1kA 1kA 10kA 100kA

A

B

103s

102s

10s

1s

10-1s


0.1s

1s

10s

100s

1E3sA

B

Time-current Selectivity


selectivity

In the gure at the side an absorption o current rom other loads has been

assumed


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Time selectivity

This type o selectivity is an evolution o the previous one.In this type o coordination, apart rom the trip thresholdin terms o current, a trip time is also dened: a certaincurrent value will make the protections trip ater a denedtime delay, suitable or allowing any protections placedcloser to the ault to trip, excluding the area which is theseat o the ault.The setting strategy is thereore to progressively increasethe current thresholds and the trip delays as one getscloser to the power supply sources (level o setting di-rectly correlated to the hierarchical level).The delayed trip thresholds must take into account the

tolerances o the two protection devices and the eectivecurrents which circulate in them.The dierence between the delays set or the protectionsin series must take into account the ault detection andelimination times o the device on the load side and othe inertia time (overshoot) o the device on the supplyside (time interval during which the protection can trip

even when the phenomenon is over).As in the case o current selectivity, the study is made bycomparing the time-current trip curves o the protectiondevices.Generally this type o coordination:

- is easy to study and realise;- is not very costly with regard to the protection sy-

stem;- allows even high selectivity limit values to be obtai-

ned (i Icw is high);- allows redundancy o the protection unctions.

However:- the trip times and energy levels let through by the

protections, especially by those close to the sources,are high.

It is a type o selectivity which can also be made

between circuit-breakers o the same size, equippedwith electronic releases with delayed protection againstshort-circuit.

Operatively speaking

The protections against short-circuit o the two circuit-breakers will be set:

- with the I2 trip thresholds against delayed short-circuit adjusted so as not to create trip overlapping,

taking into consideration the tolerances and the real currents circulating in the circuit-breakers.

- with t2 trip times adjusted so that the load-side circuit-breaker B extinguishes the ault whereas thesupply-side circuit-breakerA, still in the timing phase, manages to see the extinction o the current

and thereore remains closed.

The ultimate selectivity limit which is obtained is equal:

to the instantaneous trip threshold o the supply-side protection,

i this unction is enabled, less any tolerance:

Is = I3minA

to the value o Icw or supply-side air circuit-breakers when the

instantaneous protection unction is set to OFF.

Note

These selectivity limits are exceeded in all the cases where energy type

selectivity is realised.

I the settings indicated or energy selectivity are respected or the com-

binations o circuit-breakers with an energy selectivity value given in the

coordination tables published by ABB, the selectivity limit to be taken into

consideration is the one given in the tables and not the one which can be

obtained rom the considerations made in this paragraph. 0.1kA 1kA 10kA 100kA

Time Selectivity

A

B

Is103s

102s

10s

1s

10-1s

10-2s

104s

A

B


selectivity


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Energy selectivityCoordination o energy type is a particular type o selec-tivity which exploits the current-limiting characteristicso moulded-case circuit-breakers. It is pointed out that acurrent-limiting circuit-breaker is a circuit-breaker witha suciently short trip time to prevent the short-circuitcurrent rom reaching the peak value which would othe-rwise be reached (IEC 60947-2).In practice, all the ABB SACE moulded-case circuit-breakers o the Tmax series, the modular circuit-breakersand the E2L E3L air current-limiting circuit-breakers havemore or less marked current-limiting characteristics.Under short-circuit conditions, these circuit-breakers

are extremely ast (trip times in the region o a ew milli-seconds) and open when there is a strong asymmetricalcomponent. It is thereore not possible to use the time-

current trip curves o the circuit-breakers, obtained withsymmetrical sinusoidal types o wave orms, or thecoordination study.The phenomena are mainly dynamic (thereore propor-tional to the square o the instantaneous current value)and are heavily dependent on the interaction betweenthe two pieces o apparatus in series. Thereore theenergy selectivity values cannot be determined by theend user.The manuacturers make tables, slide-rules and calcu-lation programmes available where the ultimate currentselectivity values o Is under short-circuit between di-erent combinations o circuit-breakers are given. Thesevalues are dened by theoretically integrating the results

o tests carried out in compliance with what is indicatedin Annex A o the IEC 60947-2 Standard.

Operatively speaking

The Is ultimate selectivity limit obtained is the one given in the tables which ABB SACE makes available to the customer.

The protections against short-circuit o the two circuit-breakers must respect the conditions given below.

- Supply-side release o thermomagnetic type

the magnetic trip thresholds must be such so as not to create trip overlapping, taking into consideration the tolerances

and the real currents circulating in the circuit-breakers;the magnetic threshold o the supply-side circuit-breaker must be equal to or higher than10xIn or set to the maximum

value when it is adjustable.

- Supply-side release o electronic type

any protections against delayed short-circuit S must be adjusted ollowing the same indications as time selectivity;the instantaneous protection unction I o the supply-side circuit-breakers must be set to o

I3=OFF

B

Supplyside

T5

N,S,H,L,W

Release

In [A] 400 630 400 630

TM LL

Version

Load side

T3

N

S

TM 160

In [A]

63

80

100

125160

200

250

63

80

100

125

160

200

250

25

25

25

20

25

25

25

20

25

25

25

20

25

25

25

20

25

25

25

2020

25

25

25

20

20

25

25

25

2020

20

20

25

25

25

20

20

20

20

25

25

25

2020

20

20

25

25

25

20

20

20

25

25

25

2020

20

20

25

25

25

20

20

20

20

25

25

25

2020

20

20

25

25

25

20

20

20

20

A

Energy Selectivity

0.1kA 1kA 10kA

A

B

Is

103s

102s

10s

1s

10-1s

10-2s

A

B


selectivity

Selectivity techniques


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Zone selectivity

This type o coordination is an evolution o time coor-

dination.

In general, zone selectivity is made by means o dialogue

between the current measuring devices which, once

the setting threshold has been detected as having been

exceeded, allows just the ault zone to be identied cor-

rectly and the power supply to it to be cut o.It can be realised in two ways:

the measuring devices send the inormation linked

to the current setting threshold having been exceeded

to a supervision system and the latter identies which

protection has to intervene; when there are current values higher than their setting,

each protection sends a lock signal by means o a direct

connection or a bus to the hierarchically higher level pro-tection (on the supply side in relation to the power fow

direction) and, beore intervening, checks that a similar

lock signal has not arrived rom the load-side protection.

In this way only the protection immediately to the supply

side o the ault intervenes.

The second case allows denitely shorter trip times.

Compared with coordination o the time type, the needto increase the intentional delay as one moves towards

the power supply source is no longer necessary. The

delay can be reduced to the time needed to excludethe presence o a possible lock signal coming rom the

load-side protection.

This is a type o selectivity suitable or radial networks

and, when associated with the directional protection,

also suitable or meshed networks.Compared with coordination o time type, zone selec-

tivity allows:

- reduction o the trip times (these can be lower than

hundred milliseconds);

- reduction both o the damage caused by the ault and

o intererences to the power supply system;

- reduction o the thermal and dynamic stresses on the

components o the installation;- a very high number o selectivity levels to be obtai-

ned.

However:

- it is more burdensome both in terms o cost and o

complexity o the installation

- it requires an auxiliary supply.

This solution is thereore mainly used in systems with

high rated current and short-circuit current values, with

saety and service continuity requirements which are both

binding: in particular, there are oten examples o logical

A remains closed

B opens

A opens

B remains closed

A

B

Fault current

Lock signal

A

B

Fault current

Lock signal

Operatively speakingThis is a type o selectivity which can be realised:

- between Emax air circuit-breakers equipped with PR122 and PR123 releases.The ultimate selectivity limit which can be obtained is equal to the Icw Is = Icw

- between Tmax T4L,T5L and T6L moulded-case circuit-breakers equipped with PR223 EF releases.

The ultimate selectivity limit which can be obtained is 100kA Is = 100kA

Then, by means o the S51/P1 contact module, it is possible to make a chain o zone selectivity between Tmax and Emax. It is also

possible to realise a selectivity chain including ABB MV protections.

The operating principle o zone selectivity betweenABB circuit-breakers is as ollows:

When there are current values higher than their setting, each protection sends a lock signal by means o a direct connection or a bus to

the hierarchically higher level protection (on the supply side in relation to the power fow direction) and, beore intervening, checks that

a similar lock signal has not arrived rom the load-side protection. In this way only the protection immediately to the supply side o the

ault intervenes.


selectivity


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How to obtain selectivity with ABB circuit-breakers

MCB

Miniature Circuit-Breakers

These are the System Pro-M series o circuit-breakers.

They are equipped with thermomagnetic releases whose

trip characteristics conorm to the IEC60898 Standard

and to the DIN VDE 0660 Standard.

These circuit-breakers have the breaking capacity (Icu)

complying with the Standard IEC 60947-2 and the energy

selectivity limits reer to this Standard.

ACB

Air Circuit-Breakers

These are the Emax series o circuit-breakers.

They can be equipped with electronic releases.

The most advanced electronic releases o the Emax

series are the PR122/P, which allows zone selectivity to

be realised, and the PR123/P which, apart rom zone

selectivity, also allows directional zone selectivity to berealised.

MCCB

Moulded-Case Circuit-Breakers

These are the Tmax series o circuit-breakers.They can be equipped with thermomagnetic or electronic

releases.

The most advanced electronic release o the Tmax series

is the PR223EF which allows zone selectivity to be reali-

sed between moulded-case circuit-breakers.

Types o ABB circuit-breakers

How to obtain selectivity with the dierent types o ABBcircuit-breakers will be analysed in details in the next

chapters.

Each chapter is dedicated to a particular combination

o circuit-breakers and to the methods to realise selec-

tivity between them.This pubblication gives indicationsor rapid selection o the circuit-breaker adjustments in

order to obtain selectivity.

These indications about adjustments o the releases

are generally valid and are used or rapid selection o

the settings.

For specic combinations o circuit-breakers and orspecic installation conditions, ABB SACE may provideindications which do not respect the rules given in this

document.

Here is a short description o the dierent types o ABB

circuit-breakers taken into consideration in this publi-

cation.


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Supply-side S200 / Load-side S200Only current type selectivity can be looked or between two circuit-breakers o the S200 series.

In particular, the ollowing prescriptions are valid:

- In the overload zone, the load-side circuit-breaker must trip more rapidly than the supply-side circuit-breaker, taking into considerationthe tolerances and the eective currents circulating in the circuit-breakers.

In the short-circuit zone given that the ollowing are:

I3minA

the lowest magnetic threshold o the supply-side circuit-breakerA

I3MaxB

the highest magnetic threshold o the load-side circuit-breaker BIk

Bthe maximum prospective short-circuit current on the load side o B

These are circuit-breakers with a thermomagnetic relea-se and thereore neither time selectivity let alone zone

selectivity is possible.

The two selectivity techniques which can be used are

This is assuming that the magnetic trip thre-

sholds o the supply-side circuit-breaker and othe load-side circuit-breaker do not create trip

overlapping, taking into consideration the realcurrents circulating in the circuit-breakers.

I the ollowing relationships are veried:

I3minA

> IkB

I3MaxB

< IkB

one can talk about total selectivity.

Otherwise there will be partial selectivity and

the ultimate selectivity limit will be:

Is = I3minA

Supply-side S290D-S800D / Load-side S200Between the S800 curve D or S290 curve D circuit-breakers on thesupply side and the circuit-breakers o the S200 series on the load

side, ABB SACE provides selectivity tables which give the values

o energy selectivity.In particular, or the values o the tables to be considered valid, the

ollowing prescriptions are valid:

- in the overload zone, the load-side circuit-breaker must tripmore rapidly than the supply-side circuit-breaker, taking into

consideration the tolerances and the real currents circulating in

the circuit-breakers.

- in the short-circuit zone, the lower magnetic trip threshold

o the supply-side circuit-breaker and the upper magnetic trip

threshold o the load-side circuit-breaker must be such so as

not to create trip overlapping, taking into consideration the realcurrents circulating in the circuit-breakers.

current selectivity and energy selectivity. Depending onthe type o MCB on the supply side, either one or the

other can be realised.

A

B

Cable

IkB

Energy selectivity between S200 D40 and S200 C10

0.1kA 1kA 10kA0.1kA

Is

A

B

103s

102s

10s

1s

10-1s

10-2s

Energy selectivity between S290 D100 and S200L C25

0.1kA 1kA 10kA0.1kA

Is

B

A

103s

102s

10s

1s

10-1s

10-2s

S800N-S

D

32

S200L C 5

In [A]

6-8

10

1316

20

25

32

40

Icu [kA]

D

40 50 63

36-5015

80 100

S290

T

5

4.54.5

3.5

3.5

T

T

TT

5

5

4.5

0.6

0.6

0.60.6

0.8

0.8

0.80.8

0.8

0.8

1.1

1.1

1.11.1

1.1

1.1

0.9

1.4

1.4

1.41.4

1.3

1.3

1.1

1.1

B

A

Supplyside

Characteristic

Load side

MCB-MCB Selectivity

A

B

HowtoobtainselectivitywithABBcircuit-breakers

The Is ultimate selectivity limit which is obtained is the one given inthe tables which ABB SACE makes available to the customer


16/56



B

Supply side

Release

Iu [A]

Version

Load side In [A]Icu [kA]Charact.

TM,M

N,S,H,L

T2

EL

160

C

B-C

S200P

25

15

12.5 16 20 25 32 40 50 63 80 100 125 160 10 25 63 100 160

2

3

4

6

8

10

13

16

20

25

32

40

50

63

T

15

15

5.5*

T

15

15

5.5

T

15

15

5.5

5.5

3*

3*

T

15

15

5.5

5.5

3

T

15

15

5.5

5.5

3

3

3*

3*

T

15

15

5.5

5.5

3

3

3

T

15

15

5.5

5.5

4.5

4.5

4.5

3

3*

3*

T

15

15

10.5

10.5

7.5

7.5

5

5

5

T

15

15

15

15

8.5

7.5

7.5

6

6

6

5.5*

3*

T

17

17

17

17

17

12

12

10

10

7.5

7.5

5*

5*

T

T

T

T

T

T

20

20

15

15

12

12

7.5

T

T

T

T

T

T

T

T

T

T

T

T

10.5

10.5

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

10.5

T

T

T

T

T

T

T

T

T

T

T

T

10.5

10.5

A

Supply-side T1-T2-T3-T4 / Load-side MCBIn the Coordination Tables publication, there are tables with circuit-breakers o the Tmax T1, T2, T3and T4 series on the supply side o the modular circuit-breakers o the S200, S290 and S800 series.

The energy selectivity values given are valid once the conditions described below are veried.

The case where selectivity is looked or between a moul-ded-case circuit-breaker on the supply side and a modu-

lar circuit-breaker on the load side is now analysed.

The Is ultimate selectivity limit which is obtained is the one given in the Coordination Tables publication

Overload zone

In the overload zone,the load-side circuit-breaker must trip more

rapidly than the supply-side circuit-breaker, taking into considera-

tion the tolerances and the real currents circulating in the circuit-breakers.

Short-circuit zoneSupply-side circuit-breaker o thermomagnetic type

The magnetic trip threshold must be:

- higher than or equal to 10xIn when the magnetic threshold is

xed (TMD)- set to the maximum value when the magnetic threshold is

adjustable (TMA)

- such so as not to create trip overlapping with the load-side

circuit-breaker, taking into consideration the tolerances andthe real currents circulating in the circuit-breakers.

Supply-side circuit-breaker o electronic type

The instantaneous protection unction I must be set to OFF

I3=OFF

The I2 current threshold o unction S, less any tolerance, must be

adjusted so as not to create trip overlapping with the upper ma-gnetic threshold o the load-side circuit-breaker I3

MaxB, taking into

consideration the real currents circulating in the circuit-breakers.

With regard to the t2 trip time o unction S:

t2A 100ms both with I2t=const as well with t=const


Selectivity between T2160 PR221 In100 and S280 C50

0.1kA 1kA 10kA

103s

102s

10s

1s

10-1s

10-2s

104s

Is

B

A

MCCB-MCB Selectivity

In this case, thanks to the dierent size o the twocircuit-breakers, it is always possible to obtain energy

selectivity.

A

B


17/56


Supply-side T5-T6-T7 / Load-side MCBWith the Tmax T5, T6 and T7 moulded-case circuit-breakers and the modular circuit-breakers on the loadside, there is always total selectivity i the conditions described below are veried.


Selectivity between T5N400 PR221In320 and S284 D63

0.1kA 1kA 10kA

B

A

103s

102s

10s

1s

10-1s

10-2s

104s

Is

Overload zone

In the overload zone, the load-side circuit-breaker must trip morerapidly than the supply-side circuit-breaker, taking into considera-

tion the tolerances and the real currents circulating in the circuit-

breakers.

Short-circuit zone

Supply-side circuit-breaker o thermomagnetic type

The magnetic trip threshold must be:- higher than or equal to 10xIn when the magnetic threshold is

xed (TMD)

- set to the maximum value when the magnetic threshold is

adjustable (TMA)- such so as not to create trip overlapping with the load-side

circuit-breaker, taking into consideration the tolerances and

the real currents circulating in the circuit-breakers.

Supply-side circuit-breaker o electronic type

The instantaneous protection unction I must be set to OFF

I3=OFF

The Is ultimate selectivity limit is the lesser between the breaking capacity o the supply-side circuit-breaker and the breaking capacityo the load-side circuit-breaker.

With reerence to the example given in the gure above

S284D63 Icu = 15kA

T5N400 Icu = 36kA

there is thereore Is = 15kA

The I2 current threshold o unction S, less any tolerance, must be

adjusted so as not to create trip overlapping with the upper ma-gnetic threshold o the load-side circuit-breaker I3

MaxB, taking into

consideration the real currents circulating in the circuit-breakers.

With regard to trip time t2 o unction S:

t2A 100ms both with I2t=const as well with t=const

A

B


18/56



Current selectivityLooking or current selectivity between moulded-case circuit-breakers may be necessary when there are circuit-breakers o the same

size which do not have energy selectivity values in the tables.

In any case, only low selectivity values in the order o a maximum o 10 times the In rated current o the release on the supply side can

be obtained.To obtain the current type o selectivity, the ollowing prescriptions must be respected:

In the overload zone, the load-side circuit-breaker must trip more rapidly than the supply-side circuit-breaker, taking into considerationthe tolerances and the eective currents circulating in the circuit-breakers.

The case where selectivity is looked or between twomoulded-case circuit-breakers is now analysed. In this

case, dierent techniques can be used to obtain selec-tivity between the circuit-breakers:

current selectivity

or combinations o circuit-breakers which do not have

an energy selectivity value when an element with high

impedance is placed between the two

time selectivity

or combinations o circuit-breakers which do not have

an energy selectivity value and the supply-side circuit-breaker is equipped with an electronic release

energy selectivity

or the combinations given in the Coordination Tables

publication

zone selectivity

or Tmax circuit-breakers equipped with PR223EF re-

leases

I the ollowing relationships are true:

I3minA

> IkB

I3MaxB

< IkB

one can speak o total selectivity.

Otherwise there will be partial selectivity and the

ultimate selectivity limit will be:Is = I3

minA

This is assuming that the magnetic trip thresholds o

the supply-side circuit-breaker and o the load-sidecircuit-breaker do not create trip overlapping, taking

into consideration the real currents circulating in the

circuit-breakers.

In the short-circuit zone given that the ollowing are:I3

minAthe lower magnetic threshold of the supply-side circuit-breakerA

I3MaxB

the upper magnetic threshold of the load-side circuit-breaker B

IkB

the maximum prospective short-circuit current on the load side of B

A

B

Cable

IkB

A

Current selectivity between T4N250 TMA250 and T4N250 TMA80

0.1kA 1kA 10kA

B

103s

102s

10s

1s

10-1s

10-2s

104s

Is

MCCB-MCCB Selectivity



19/56


Time selectivityLooking or current selectivity between moulded-case circuit-breakers may be necessary when there are

circuit-breakers o the same size which do not have energy selectivity values in the tables and the supply-

side circuit-breaker is equipped with an electronic release with unction S (T2-T4-T5-T6-T7).In any case, only low selectivity values in the order o a maximum o 10-12 times the rated uninterrupted

current Iu o the supply-side circuit-breaker can be obtained.

To obtain the time type o selectivity, the ollowing prescriptions must be respected:

In the overload zone, the load-side circuit-breaker must trip more rapidly than the supply-side cir-

cuit-breaker, taking into consideration the tolerances and the real currents circulating in the circuit-breakers.

t2 times set

MCCB on the supply side t2A=250 t2

A=250 t2

A=500

MCCB on the load side t2B=50 t2B=100 t2B =250

Note

The indications about the adjustments o the releases are valid in general and useul or a rapid choice o setting guaranteing selectivity. For specifc

combinations o circuit-breakers and or specifc installation conditions, ABB SACE may provide indications which do not respect the rules given in

this document, but however able to ensure selectivity.

The ultimate selectivity limit is equal to the istantaneus trip threshold I3 o the upstream circuit-breaker minus the tollerance

Is = I3minA

In the short-circuit zone

- the I2A

current threshold o unction S o the supply-side

circuit-breaker must be adjusted so as not to create trip over-lapping with the current threshold o the protection against

short-circuit (I3 or I2) o the load-side circuit-breaker, takinginto consideration the tolerances and the real currents circu-

lating in the circuit-breakers

- with regard to trip time t2 o unction S, the settings o theMCCBs on the supply side are indicated below according to

the setting/type o MCCB on the load side:

when the I2A

threshold o the supply-side circuit-breaker ishigher than an instantaneous protection o the load-side cir-

cuit-breaker (magnetic, I3=ON or sel-protection) the ollowing

is valid:

t2A 150ms i I2t =const

t2A 100ms i t =const

when the I2A

threshold o the supply-side circuit-breaker is only

higher than the I2B

threshold o the load-side circuit-breaker,

by using curves with the same characteristics, the ollowing

is valid:

t2A

- tolerance t2B+ tolerance + 50ms

A

Time selectivity between two T4

0.1kA 1kA 10kA

B

Is103s

102s

10s

1s

10-1s

10-2s

104s

This relationship must be respected when, through the dialogue or the PR010T unit, electronic settings are used. In the more requent

case - use o the available settings through dip-switches - the values given in the ollowing tables must be complied with:

A

B



20/56



Energy selectivityABB SACE makes selectivity tables available to the customer which providethe energy selectivity valuesat 415V between the possible combinations o moulded-case circuit-breakers.Since the moulded-case circuit-breakers can be equipped with thermomagnetic and electronic releaseswhich are both adjustable, it is necessary or the user to carry out some checks in order to obtain selec-tivity up to the short-circuit current value given in the tables.In the overload zone, the load-side circuit-breaker must trip more rapidly than the supply-side circuit-breaker, taking into consideration the tolerances and the real currents circulating in the circuit-breakers.


Note: The indications about the adjustments o the releases are valid in general and useul or a rapid choice o setting guaranteing selectivity. For

specifc combinations o circuit-breakers and or specifc installation conditions, ABB SACE may provide indications which do not respect the rules

given in this document, but however able to ensure sectivity.

The Is ultimate selectivity limit obtained is the one given in the

Coordination Tables publication.

Iu [A]

N,S,H,L

T6

MCCB - Tmax T5 @ 400/415 V

T7

S,H,L,V(1)

TM, M EL EL

630 1600

400630

400

630

TM

EL

N,S,H,L,V

T5

In [A]

320400500320400630

30

3030

630 800(2) 1000(2) 1250 1600

TTTTTT

TTTTTT

TTTTTT

TTTTTT

800

3030

3030

800

630

30

3030

630

800

3030303030

800

1000

303030303030

1000

800 1000 1250

Supply side

Versions

Release

Load side

t2 times set

MCCB on the supply side t2A=250 t2

A=250 t2

A=500

MCCB on the load side t2B=50 t2

B=100 t2

B=250

This relationships must be respected when, through the dialogue or the PR010T unit, electronic settings are used. In the more re-quent case - use o the available settings through dip-switches - the values given in the ollowing tables must be complied with:

Supply-side circuit-breaker o thermomagnetic type(T1-T2-T3-T4-T5-T6)The magnetic trip threshold must be:- higher than or equal to 10xIn when the magnetic threshold is

xed (TMD)- set to the maximum value when the magnetic threshold is

adjustable (TMA).- such so as not to create trip overlapping with the load-side

circuit-breaker, taking into consideration the tolerances and

the eective currents circulating in the circuit-breakers.

Supply-side circuit-breaker o electronic type(T2-T4-T5-T6-T7)- the instantaneous protection unction I must be set to OFF

I3=OFF

- trip threshold I2A

o the supply-side circuit-breaker must beadjusted so as not to create trip overlapping with the tripthreshold o the protection against short-circuit (I3 or I2) o theload-side circuit-breaker, taking into consideration the toleran-ces and the real currents circulating in the circuit-breakers

- with regard to trip time t2 o unction S, the settings o theMCCBs on the supply side are indicated below according tothe setting/type o MCCB on the load side:when the I2

Athreshold o the supply-side circuit-breaker is

higher than an instantaneous protection o the load-side cir-cuit-breaker (magnetic, I3=ON or sel-protection) the ollowing

is valid:

t2A 150ms i I2t =const

t2A 100ms i t =const

when the I2A

threshold o the supply-side circuit-breaker isonly higher than threshold I2

Bo the load-side circuit-breaker,

by using curves with the same characteristics, the ollowing

is valid:

t2A


Energy selectivity between thermomagnetic MCCB

A

0.1kA 1kA 10kA

B

Is

103s

102s

10s

1s

10-1s

10-2s

A

Energy selectivity between electronic MCCB

0.1kA 1kA 10kA

B

Is

103s

102s

10s

1s

10-1s

10-2s

A

B



(1) Available only with Iu 1250 A(2) Value valid only or PR232/P,

PR331/P and PR332/P trip units


21/56


Zone selectivity (T4L-T5L-T6L)By means o the new PR223EF electronic release, it is possible to

realise zone selectivity between moulded-case circuit-breakers o

the Tmax T4L, T5L and T6L series.

The PR223EF implements the new EF protection unction, ca-pable o detecting the short-circuit at its onset. This is thanks to

predicting the ault, based on analysis o the trend o the current

derivative in relation to the time, di(t)/dt vs i(t).

I the EF protection is enabled, it intervenes or aults o considera-ble size, replacing the I protection unction against instantaneous

short-circuit when there is an auxiliary power supply.

Between PR223EF releases, zone selectivity is implemented simul-taneously on unctions S, G and EF. It is carried out by means o an

interlocking protocol (Interlocking, IL), guaranteed by a coupleo

shielded twisted pair cables or modbus RS485 which connect the

circuit-breakers equipped with the PR223EF (ask ABB or urtherinormation about cable type).

In the case o a short-circuit, the circuit-breaker immediately to the

supply side sends a lock signal to the hierarchically higher level

protection by means o the bus and, beore trippping, checks thata similar lock signal has not come rom the load-side protection.

System integrity is controlled by a monitoring unction: in the case

o a short-circuit, i a ault is ound in the interlocking system, the

EF protection unction trips (with trip times in the order o tens oms), but zone selectivity is not guaranteed.

Furthermore, i the load-side circuit-breaker does not manage to

trip, it asks the supply-side circuit-breaker or help and the latter

opens even i it does not detect the ault (SOS unction).A 24Vdc auxiliary power supply is required or operation o the EF

protection and zone selectivity.

The ultimate selectivity limit which can be obtained is 100kA

Is=100kA

All the protection unctions can be programmed remotely, exploi-ting the dialogue unction on the release, or locally by means o

the PR010/T, which can be connected to a serial port on the ront

o the PR223EF.One o the main advantages in using zone selectivity between

MCCBs is the reduction in size o the circuit-breakers it makes

possible.

In act, in looking or selectivity between moulded-case circuit-

breakers with the classic techniques, it is oten necessary to increa-se the size o the supply-side circuit-breakers to obtain selectivity

limits congruous with the short-circuit current o the installation.

By means o suitably cabled PR223EF releases, it is possible toobtain 100kA o selectivity even between two circuit-breakers o

the same size.

An example is given below (see pages 22 and 23) o how, by means

o zone selectivity between moulded-case circuit-breakers, a re-duction in sizes and a considerable reduction in the peak current

and specic energy let through by the circuit-breakers is possible,

whilst still maintaining total selectivity.

Interlock confgurationEach release is characterised by:

- an input destined or connection with the release on the supplyside Uplink

- an output destined or connection with the release on the load

side Downlink

Each o the two can be congured in two ways: PP (point-point)

or MP (multi-point) according to the installation condition the

releases are in.

The main congurations are given below:

Uplink: PP/MP

Downlink: PP/MP

PR223EF

MP PP

MPMPMP

PR223EFPR223EFPR223EF

PR223EFMP

MPMPMP


PR223EFPP

PP

PR223EF

PR223EF



22/56



The main parameters, characteristic of the release, are:

Trip delayed Enabling this parameter introduces a trip delay in the case when, on the load side o a release, smaller sized

Tmax or modular circuit-breakers are installed. The aim o this parameter is to obtain selectivity with the

other devices on the load side not equipped with PR223EF.

This parameter is only enabled in the circuit-breakers which have the device outside the zone selectivity

chain on the load side.

EF enable/disable Enabling/disabling protection EF.I protection EF is enabled:

the presence o Vaux leads to automatic exclusion o unction I and enabling o protection EF,

the lack o Vaux leads to exclusion o protection EF and to the return o unction I (i enabled).

100 kA Ultimate selectivity limit which can be obtained with the PR223EF suitably cabled and supplied with power.

16 Maximum number o releases which can be connected to the BUS o a level.

1000 meters Maximum overall length o the connection cable. Cabling the dierent releases is carried out as in the classicBus topology (see fgure).

UPUPUP


PR223EF

Down

= max 1000 mCable RS485




23/56


Zone selectivity between Tmax

0.1kA 1kA 10kA

B AC

103s

102s

10s

1s

10-1s

10-2s

104s

A

B

C

Trip delayed ON

PR221DS

PR223EF

PR223EF

Indications about the settingsTo obtain total selectivity, both in the case o overload and short-circuit, using the PR223EF releases suitably cabled and supplied withpower, making the ollowing selections and the ollowing settings between the various circuit-breakers is recommended:

- Trip delayed

By enabling this parameter on the releases which have a circuit-

breaker directly on the load side not equipped with PR223EF,

selectivity is obtained with the Tmax o a smaller size or theMCBs placed on the load side.

Overload

- Check there is no trip overlapping o protection unctions L(against overload), taking into consideration the tolerances and


Short-circuit

- No trip overlapping o the I2 current thresholds o unction S,

taking into consideration the tolerances and the real currents

circulating in the circuit-breakers.

- Trip time t2

Adjusted so as to realise time selectivity with any load-sidecircuit-breaker placed outside the zone selectivity chain.Between the circuit-breakers equipped with PR223EF and inter-

locked with each other, i A is the supply-side circuit-breaker and

B the load-side circuit-breaker, the ollowing must be valid:

t2A t2B.

When possible, it is advisable to look or time type selectivity as

well between the interlocked circuit-breakers so as to guarantee

partial selectivity in case the auxiliary power supply is lost.

- Instantaneous protection unction I

This protection unction is automatically disabled when unction

EF is enabled and there is an auxiliary power supply. Its settings

are thereore only o importance in the case o losing Vaux.



24/56



V = 400 VIk = 95 kAU

L

LLL

Switchboard A

Switchboard B

QF1E3H800 PR122/P-LSI In800

WC16x(1x400)+2x(1x240)+1G400Ib = 740 AIz = 1050 A

L = 17mPVC

QF1E3S/ S1000

QF2T6L630 PR222DS-LSI In630

QS2T6D630

IkA=74 kA

QF3T4L250 PR222DS-LSI In250

L1In = 200 A

QF4T4H250 PR222DS-LSI In250



L2In = 200 A

L3In = 170 A

L4In = 170 A

IkA=54.5 kA

WC26x(1x300)+2x(1x150)+1G300Ib = 540 AIz

= 682 AL = 25 mPVC

WC33x(1x150)+1x(1x95)+1G95Ib = 200 AIz = 275 AL = 10mPVC

WC43x(1x95)+1x(1x50)+1G50Ib = 200 AIz = 207 A

L = 40mPVC

WC53x(1x95)+1x(1x50)+1G50Ib = 170 AIz = 207 A

L = 60mPVC

WC63x(1x95)+1x(1x50)+1G50Ib = 170 AIz = 207 A

L = 30mPVC

Example o applicationIn the ollowing example a comparison between an installation where selectivity is implemented with traditional techniques and the sameinstallation with selectivity ensured by EFDP system is given.

Traditional installation

The choice o the protection devices shall be carried out above all making reerence to the rated currents o the loads and to the short-circuit current o the busbars. Besides, this choice is infuenced by the search or selectivity realized through traditional techniques, whosevalues can be ound in the Coordination Tables publication.The short-circuit current at the busbars o switchboard B (Ik

B=54.5kA) infuences the choice o the protection devices and imposes the

use T4H 250 circuit-breakers on the outgoing eeders.In order to guarantee selectivity, the circuit-breaker (QF2) on the supply side o switchboard B and installed in switchboard A must beT6L 630 type.The busbar o switchboard A is characterized by a short-circuit current value Ik

A=74kA: this aects deeply the choice o the upstream

protection device which, independent o the rated current, shall be an Emax circuit-breaker and precisely an Emax E3H, thereore able

to guarantee selectivity towards the apparatus on the load side.Each switchboard has got as main device a switch-disconnector, which shall be protected against short-circuit and overload by thecircuit-breaker on the supply side. Generally speaking, in order to guarantee protection, it is necessary to use a switch-disconnector inthe version derived rom the circuit-breaker on the supply side.Thereore it is evident that the selectivity requirements condition deeply the choice o the protection devices and direct it towards die-rentiated sizes according to the location o the circuit-breakers in the installation.




25/56


Installation with PR223EF

Since the rated current and the short-circuit values o the network under consideration remain unchanged, the use o the new protectionrelease PR223EF allows selectivity to be obtained without increasing the size o the apparatus to be used.

In particular, a T5L630 equipped with PR223EF can be used as circuit-breaker on the supply side o switchboard B (QF2). As a conse-

quence, the switch-disconnector on the incoming eeder o switchboard B can be reduced in size.

The most evident reduction in size which can be obtained regards the main device o the installation: thanks to the use o PR223EFrelease, a moulded-case circuit-breaker can be chosen instead o an air circuit-breaker. In this specic case, a T6L800 circuit-breaker

with a downstream switch-disconnector o the same size can be used.

V = 400 VIk = 95 kAU

L

LLL

Switchboard A

Switchboard B

QF1T6L800 PR223EF In800

WC16x(1x400)+2x(1x240)+1G400Ib = 740 AIz = 1050 A

L = 17mPVC

QF1T6D800


WC26x(1x300)+2x(1x150)+1G300Ib = 540 AIz

= 682 AL = 25 mPVC

QS2T5D630

IkA=74 kA


WC33x(1x150)+1x(1x95)+1G95Ib = 200 AIz = 275 AL = 10mPVC

L1In = 200 A




WC43x(1x95)+1x(1x50)+1G50Ib = 200 AIz = 207 A

L = 40mPVC

L2In = 200 A

L3In = 170 A

L4In = 170 A

WC53x(1x95)+1x(1x50)+1G50Ib = 170 AIz = 207 A

L = 60mPVC

WC63x(1x95)+1x(1x50)+1G50Ib = 170 AIz = 207 A

L = 30mPVC

IkA=54.5 kA



26/56





The ollowing table summarizes the advantages deriving rom the use o the new electronic release.In details, it has been possible:

toreplacealarge-sizedmoulded-casecircuit-breakerwithasmalleroneT5L630PR223EFinsteadofT6L630PR221-LS; toreplacealarge-sizedaircircuit-breakerwithamuchsmallermoulded-caseoneT6L800PR223EFinsteadofE3H800PR122/P-

LSIG;

toreplacealarge-sizedswitch-disconnectorwithasmaller-sizedoneT5D630insteadofT6D630; toreplaceanairswitch-disconnectorwithaswitch-disconnectorderivedfromamuchsmaller-sizedmoulded-casecircuit-breaker

T6D 800 instead o E3S/MS1000.

Besides a remarkable reduction in the applicable sizes, with the consequent advantages rom a dimensional and economical point oview, the installation equipped with PR223EF releases is subject to more limited electrodynamical and thermal stresses than those o the

traditional solution. Hereunder the let-through energy and peak curves relevant to the considered circuit-breakers are shown.

From the curves above, it should be noticed that at a short-circuit current value corresponding to 55kA, the specic let-through energyallowed by T6H630 is equal to 13 MA2s, whereas that o T5L630 is 3.5 MA2s. Also the peak values decrease drastically rom 54kA o T6Hto about 35kA o T5L630.Similarly, at 74kA short-circuit current, the specic let-through energy and the peak current limited by T6L800 circuit-breaker reduce verymuch the thermal and dynamical stresses i compared with E3H circuit-breaker.In particular, in this case, it is possible to use the current limiting capacities o the moulded-case circuit-breaker to optimize the dimen-sioning o the busbar system o switchboard A. In act, with an air circuit-breaker on the supply side, it is necessary to adopt a busbarsystem dimensioned or a rated short-time withstand current (Icw) equal to 75kA and consequently with a current carrying capacity muchmore higher than the total current required by the installation. On the contrary, by using a T6L800 circuit-breaker on the supply side othe switchboard, it is possible to adopt a busbar system with Icw equal to 35kA, which results more consistent rom a dimensional pointo view with 800A current, which is the current carrying capacity required to this busbar system.In details, the ollowing values correspond to 35kA rated short-time withstand current o the busbar system:- peak current Ip = (35x2.1) = 73.5kA, which results to be higher than the peak o 66kA allowed by T6L800 circuit-breaker at 75kA short-

circuit current;- let-through energy I2t = 352 x 1 =1225 MA2s, which results to be higher than the let-through energy equal to 20MA2s o T6L800 circuit-

breaker with a short-circuit value corresponding to 75kA.

10 kA

1 MA2s

103 kA

Irms [kA]

10 MA2s

102 MA2s

I2[MA2s]

E3H 800

T5L 630

T6L 800T6H 630

102 kA

103 MA2s

10 kA 103 kA

Irms [kA]

Ip[kA]

E3H 800

T5L 630

T6L 800T6H 630

102 kA

10 kA

103 kA

102 kA

Let-through energy curve Peak curve

Traditional solution Solution with EFDP

Busbars o

switchboard AIcw = 75kA Icw = 35kA

Traditional solution Solution with EFDP

E3H800 PR122/P

E3S/MS1000

T6L630 PR221DS

T6D630

T6L800 PR223EF

T6D800

T5L630 PR223EF

T5D630

QF1

QS1

QF2

QS2


27/56


ACB-MCCB Selectivity

The case where selectivity is looked or between an aircircuit-breaker on the supply side and a moulded-case

circuit-breaker on the load side is now analysed.

In this case, two paths can be ollowed:

- traditional solution with time/energy selectivity;

- zone selectivity, when the load-side circuit-breakeris a Tmax equipped with a PR223EF release and theEmax on the supply side is equipped with a PR122/P

or PR123/P release.

Traditional solutionIn this case, ABB SACE makes a table available in which the selectivity values between air circuit-breakers on the supply side and moul-ded-case circuit-breakers on the load side are given.The need to set the releases appropriately to obtain the selectivity value given in the table is obvious.The ollowing must be true:In the overload zone, the load-side circuit-breaker must trip more rapidly than the supply-side circuit-breaker, taking into considerationthe tolerances and the real currents circulating in the circuit-breakers.


- instantaneous protection unction I must be set to OFFI3=OFF

- the I2A

trip threshold o the supply-side circuit-breaker mustbe adjusted so as not to create trip overlapping with the tripthreshold o the protection against short-circuit (I3 or I2) othe load-side circuit-breaker, taking into consideration thetolerances and the eective currents circulating in the circuit-breakers

- with regard to the t2 trip time o unction S, the settings o theEmax on the supply side are indicated hereunder, accordingto the setting/type o MCCB on the load side:

when the I2Athreshold o the supply-side circuit-breaker is

higher than an instantaneous protection o the load-side cir-cuit-breaker (magnetic, I3=ON or sel-protection) the ollowing

is valid: t2

A100ms both i I2t =cost as well as i t =cost

when the I2A

threshold o the supply-side circuit-breaker is only higher than the I2B

threshold o the load-side circuit-breaker, by

using curves with the same characteristics, the ollowing is valid:

t2A


The Is ultimate selectivity limit obtained is the one given in the Coordination Tables publication.

Note

The indications about the adjustments o the releases are valid in general and useul or a rapid choice o settings guaranteeing selectivity. For speci-

fc combinations o circuit-breakers and or specifc installation conditions, ABB SACE may provide indications which do not respect the rules given

in this document, but however able to ensure selectivity.

B A

Emax-MCCB selectivity

0.1kA 1kA 10kA

103s

102s

10s

1s

10-1s

10-2s

104

s

Version

Release

Iu [A]Load side

ACB - MCCB @ 400/415 V

Supplyside

T1

T2

B

C

N

N

S

H

TM

TM,EL

E1 E2 E3

B N B N S L* N S H V L* S

EL EL EL

800100012501600

800100012501600

16002000

1000125016002000

8001000125016002000

12501600

25003200

100012501600200025003200

800100012501600200025003200

800100012501600200025003200

20002500

4000

160

160

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

55

T

T

T

T

T

65

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T


t2 times set

ACB on the supply side t2A=200 t2

A=200 t2

A=400 t2

A=700

MCCB on the load side t2B=50 t2

B=100 t2

B=250 t2

A=500

This relationship must be respected when, through the dialogue or the PR010T unit, electronic settings are used. In the more requent

case - use o the available settings through dip-switches - the values given in the ollowing tables must be complied with:


28/56



The S51/P1 contact is a clean and normally open contact, requiring

an auxiliary power supply at 24V to supply the locking signal to the

supply side relays in the selectivity chain.The contact is located inside the release and is made available

by means of connector X3. By programming it appropriately, it is

possible to send the locking signal to the SZin input of the supplyside release. Contact programming can be carried out by means ofSDTestBus2, PR010/T and all the programming instruments which

can communicate via ModBus.

S51/P1


PR122EFSZin

= max 1000 mCable RS485

S51/P1 S51/P1

Zone selectivity between Emax and TmaxBy means of the programmable contact S51/P1 on the Tmax circuit-breakers, it is possible to extend zone selectivity from the PR223EF

releases to the PR122/P, PR332/P, PR123/P or PR333/P releases on the supply side.

In practice, the contact makes interfacing between IL protocol of PR223EF and ZS zone selectivity of the releases for Emax and Tmaxpossible.

By making this selectivity chain between Emax and Tmax the limit selectivity value shall be the lesser value between:

- the short-time withstand current of the supply-side circuit-breaker (Icw of the Emax)

- the breaking capacity of the circuit-breaker on the load side (Icu of the Tmax in version L 100kA)

ACB-MCCB Selectivity



29/56


30/56




103s

102s

10s

1s

10-1s

10-2s

104s

ACB-ACB Selectivity

The case where selectivity is looked or between two air circuit-breakers is now analysed. In this case variousmethods can be used to obtain selectivity between the circuit-breakers:

time selectivity or combinations o Emax with any type o release

zone selectivity or combinations o Emax with PR122 and PR123 releases

directional time selectivity or combinations o Emax with PR123 releasesdirectional zone selectivity or combinations o Emax with PR123 releases.

Time selectivityTo obtain the maximum level o selectivity compatible with the chosen strategy, both in the case o overload and short-circuit, the ollowing

selections and the ollowing settings between the various circuit-breakers are recommended:

Minimum dierence between the t2 times o two Emax circuit-breakers equipped with PR121, PR122, and PR123

t=const t2A > t2B+ 100ms* *70ms i in aux supply or in sel-supply under steady conditions

I2t=const t2A > t2B+ 100ms t2A < 400ms

I2t=const t2A > t2B + 200ms t2A 400ms

Note

The indications about the adjustments o the releases are valid in general and useul or a rapid choice o settings guaranteeing selectivity. For specifc

combinations o circuit-breakers and or specifc installation conditions, ABB SACE may provide indications which do not respect the rules given in this

document, but however able to ensure selectivity.

With regard to the ultimate selectivity limit

- I instantaneous unction I is set to ON (I3=ON), the ultimate selectivity limit will be the value o the I3 instantaneous trip threshold othe supply-side circuit-breaker less its tolerance:

Is = I3minA

- I instantaneous unction I is set to OFF (I3=OFF), the ultimate selectivity limit is equal to the Icw value o the supply-side circuit-breaker:

Is = Icw.

Overload

- Check that there is no trip overlapping o protection unctions L

(against overload), taking into consideration the tolerances andthe real currents circulating in the circuit-breakers.

Short-circuit

- The instantaneous protection unction I o the supply-side circuit-

breaker must be set to OFF

I3A=OFF

- the I2A

trip threshold o the supply-side circuit-breaker must be

adjusted so as not to create trip overlapping with the trip threshold

o the protection against short-circuit (I3 or I2) o the load-side

circuit-breaker, taking into consideration the tolerances and thereal currents circulating in the circuit-breakers

- with regard to the t2 trip times o unction S, no overlapping o

the curves and the ollowing relationships must be respected:



31/56


Fault current

Connection with lock signal

Connection without lock signal

A

B

CPR122/P

PR122/P

PR122/P

PR122/P

PR122/P

PR122/PPR122/P

PR122/P PR122/P

PR122/PPR122/P

PR122/P

t2A

t2B

t2A

does nottrip

selectivity

timeA

selectivitytimeB

selectivitytimeC

does nottrip

does nottrip

Zone selectivity between EmaxBy means o zone selectivity, it is possible to obtain selectivity between Emax circuit-breakers, notably reducing the trip times by obtaininglower curves which can acilitate the search or selectivity towards the medium voltage circuit-breakers.

By reducing the trip times, the thermal stresses on all the components o the installation during the ault are also reduced.

Zone selectivity between Emax circuit-breakers, applicable to protection unctions S and G, can be enabled in the case where:

- the xed time curve is selected or these protections;- there is a 24V auxiliary power supply source;

- the Emax circuit-breakers are equipped with PR122 or PR123 releases.

The ultimate selectivity limit obtained is equal to the Icw o the supply-side circuit-breaker i the I3 is set to OFF

The operating principle o zone selectivity between Emax is described below.

By zone the part o the installation included between two circuit-breakers in series is intended. The ault zone is the one immediately to

the load side o the circuit-breaker which detects the ault. By means o a simple connection wire, each circuit-breaker which detects a

ault communicates this to the one on the supply side.The circuit-breaker which does not receive any communication rom those on the load side will launch the opening command in the

selectivity time set, adjustable rom 40 to 200ms.

The aim o the selectivity time is to realise time selectivity towards pieces o apparatus connected on the load side which are outsidethe zone selectivity chain (apparatus not cabled).On the other hand, the circuit-breakers which receive a lock signal rom another release, will trip according to the t2 time seto protection S.

As can be seen, i the settings indicated below have been respected, in the case o a short-circuit no circuit-breaker trips in the t2 time,

but all o them trip within the selectivity time set.

A

B

Lock signal

Fault current

A

B

Lock signal

Fault current

A t2A

B selectivity timeA selectivity timeB closed



32/56




Zone selectivity between Emax

t2A

time o selectivityA

103s

102s

10s

1s

10-1s

10-2s

104sOverload

- Check that there is no trip overlapping o protection unctions L

(against overload), taking into consideration the tolerances and


Short-circuit

- No trip overlapping o the I2 current thresholds o unction S,taking into consideration the tolerances and the real currents

circulating in the circuit-breakers.

- Trip times t2 and selectivity time adjusted in the ollowing

way:

selectivity time adjusted so as to realise time-current selecti-vity with any device connected directly on the load side placed

outside the zone selectivity chain

t2 (time o unction S) adjusted so as to guarantee no trip o theprotection which receives the lock signal, i.e. according to the

relationship:

t2A

> selectivity timeB

+70ms*

*t minumum between the trip times o two CBs in series, with auxiliary

power supply, and with constant time curves, to guarantee no trip o the

CB on the supply side.

Indications about the settingsTo obtain total selectivity, both in the case o overload, short-circuit and earth ault, using the zone selectivity unction, making theollowing selections and the ollowing settings between the various circuit-breakers is recommended:

A

B

With regard to the ultimate selectivity limit

- I the instantaneous unction I is set to ON (I3=ON), the ultimate selectivity limit will be the value o the I3 instantaneous trip thresholdo the supply-side circuit-breaker less its tolerance, i this unction is enabled:

Is = I3minA

- I the instantaneous unction I is set to OFF (I3=OFF), the ultimate selectivity limit is equal to the Icw value o the supply-side circuit-

breaker:

Is = Icw.

ACB-ACB Selectivity



33/56


Indications about cablingTo carry out the cabling, a two-wire shielded corded cable can be used (Vn50V; AWG 22; nominal conductor DC resistance@20C 15Ohm/1000t; nominal outer shield DC resistance@20C 3 Ohm/1000 t). The shield must only be connected to earth on the release o

the supply-side circuit-breaker.The maximum cabling length or zone selectivity between two units is 300 metres. This limit can be increased with special mechani-

sms.

The maximum number o circuit-breakers which can be connected to the outputs (Z out) o a release is 20.

Thelock signal o the release is a +24V signal.

Repetition o the signal

As shown in the table, in the case where one release receives the lock signal on the load side, even i it has not entered the threshold o

unction S, it will repeat the lock signal on the supply side.

This to avoid any setting errors, i.e. a release on the load side not having entered the threshold, but a release on the supply side having

entered the threshold, leading to lack o selectivity:

Zone Selectivity I > I2 ZSI signal ZSO signal T trip time

Excluded NO 0 0 no trip

Excluded NO 1 0 no trip

Excluded YES 0 0 t2 programmed

Excluded YES 1 0 t2 programmed

Inserted NO 0 0 no trip

Inserted NO 1 1 no trip

Inserted YES 0 1 selectivity time

Inserted YES 1 1 t2 programmed

ZSA MODULE

In the case where several load-side circuit-breakers have to lock several supply-side circuit-breakers, but in a dierent way, it is necessary

to use the ZSA module supplied byABB.

A B

C D

A B

C D

ZSA


With reerence to the gures at the side, let us suppose, or exam-

ple, that:

C must lockA and B

D must only lock B.

With the cabling made as in the gure at the side, it would not be

possible to obtain the desired solution.

In act, the lock signal coming rom D would also be transmitted to

A by means o the electrical continuity which is created between

the dierent B-C and C-A interlocking connections.

By means o suitable cabling o the ZSA module, the lock signal

is made one-way so that a signal coming rom D towards B is not

transmitted toA as well.The gure at the side shows use o the ZSA module.


34/56



Directional time selectivityBy means o the directional protection D present on the Emax circuit-breakers equipped with PR123 releases, it is possible to realise

time selectivity o directional type.

This type o selectivity has all the advantages and limits o time selectivity realised by means o unction S,but is also able to trip within

dierent times according to the direction o the ault.

Using this type o selectivity is particularly recommended in all those cases where there is more than one power supply source.

In act, in the case o a ault near a source, service continuity o the remaining power supply can be guaranteed by means o

directional protection.

Directional protectionDirectional protection is based on the possibility o correlating the circuit-breaker behaviour with the direction o the ault current whichpasses through it in relation to the reerence direction which can be set on the release.According to the direction o the current, it is possible to set two dierent trip times on the PR123 release:a time (t7Fw) in a direction concordant (Fw) with the reerence direction set;

a time (t7Bw) in a dire

Documents

Low Voltage Selectivity QT1_EN