| AUTOMATION

GRID

MMLG 01, 02, 03, 04 Test Blocks

Technical Data

MMLG_EN_TD_A

Note: The technical manual for this device gives instructions for its installation, commissioning, and operation. However, the manual cannot cover all conceivable circumstances or include detailed information on all topics. In the event of questions or specific problems, do not take any action without proper authorization. Contact the appropriate Alstom Grid technical sales office and request the necessary information.

Any agreements, commitments, and legal relationships and any obligations on the part of Alstom Grid including settlements of warranties, result solely from the applicable purchase contract, which is not affected by the contents of the technical manual.

This device MUST NOT be modified. If any modification is made without the express permission of Alstom Grid, it will invalidate the warranty, and may render the product unsafe.

The Alstom Grid logo and any alternative version thereof are trademarks and service marks of Alstom Grid.

All trade names or trademarks mentioned herein whether registered or not, are the property of their owners.

This manual is provided for informational use only and is subject to change without notice.

© 2010, Alstom Grid. All rights reserved.

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Types MMLG 01, 02, 03, 04 Test Blocks.Types MMLB 01 Multi-finger Test Plug/MMLB 02 Single-finger Test Plug

Features

• Test block can be mounted adjacent toMidos modular relays and systems

• Test block obviates need to disturbprotective system wiring for testing

• Monitoring, isolation and secondaryinjection testing are simplified andquickly performed

Types Available• MMLG 01

Standard test block

• MMLG 02Special test block designed for use inbusbar protection schemes

• MMLG 03Horizontal version of MMLG 01

• MMLG 04Horizontal version of MMLG 02

• MMLB 01Multi-finger test plug

• MMLB 02Single-finger test plug

MMLG 01 and MMLB 01terminals 13 and 14 must not be usedfor CT connections since they maypresent a safety hazard.

ApplicationAlthough designed within the Midosrange these test blocks offer facilities formonitoring and secondary injectiontesting any power system protectionscheme, when used with the multi-fingered test plug type MMLB 01.

A single-finger test plug, type MMLB 02 isalso available for monitoring the currentflow in individual circuits which havebeen routed through the test block.

Before use, the insulation of theflying leads should be visuallychecked for damage.

The continuity of the shorting plug/wirelinks, and the state of their insulation,should be checked before insertion intothe MMLG 01 test block.

Description, Installation andUseThe Safety Statements Publication R5948should be read before installing or usingthe test block (MMLG) or test plug(MMLB).

Note. Terminals 13 and 14 haveshort contact fingers which mustnot be used for CT connections.

Refer to the Mechanical Details sectionfor a description of the test block(MMLG) and test plug (MMLB). TheMMLG cover, when in place, providesprotection from electric shock hazard.

Care should be taken to ensure thatMMLG 01 covers are correctlyorientated when replaced.

The test block carries 14 circuits, each ofwhich is brought out to separate pairs ofterminals at the rear of the case.

Each circuit comprises a pair of internalcontacts which are normally sprungtogether to complete the circuit linkthrough the block when the associatedprotective equipment is in normalservice.

Access to these internal circuits fortesting purposes, can be gained byremoving the front cover. A metallicprobe secured to the inside face of theMMLG 01 cover is automaticallywithdrawn when the cover is removed,so interrupting the circuit betweenterminals 13 and 14. By routing themain dc auxiliary supply to theprotection scheme or relay through thiscircuit, removal of the test block coverwill thereby prevent inadvertent trippingof the protection during the ensuing tests.

Figure 1

Type MMLG 01 test block

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This link is not provided on the MMLG 02 because the contacts betweenterminals 13 and 14 are normallyclosed.

Note. These two terminals on MMLG01/02 must not be used for CTconnections since this will present asafety hazard. The reason for this is thatthe associated MMLB 01 test plugcontact finger is shorter than the others.This would result in an open circuit pathon MMLG 02.

Removal of the cover also reveals anorange coloured strip on the block frontplate which gives a clear visualindication that the scheme is out ofservice.

Insertion of the test plug type MMLB 01, as shown in Figures 2 and 3,open circuits the contacts which connectterminal pairs.

The test plug carries 28 4mm sockets.Each socket is identified by a numberwhich corresponds to the numbered caseterminal to which the socket is connectedwhen the plug is inserted.

The MMLB 02 single-finger test plug canbe inserted into individual test positions inthe test block as shown in Figure 7. Seenotes (a) and (b) below.

Notes.

(a) Before using this test plug, refer to the current and voltages measurements warning.

(b) The continuity of the test plug leadsand the state of their insulationshould be checked before insertioninto the MMLG test block.

Current measurementsThis single-finger test plug allows thecurrent in any of the circuits routedthrough the test block to be monitored.When using the single-finger test plug tomonitor secondary CT current, the leadsfrom this must never be open circuited,otherwise lethal voltages may begenerated. Before the single-finger testplug is inserted into the test block, theconnected ammeter must be on thecorrect range. With this plug in the testblock, the ammeter range must not bechanged. This avoids potentially lethalvoltages being generated.

Voltage measurementsHazardous live voltages will beaccessible via the single-finger test plugleads when using this for voltagemeasurements.

Connections to other equipment, eg.,CTs, VTs and dc supplies, should bemade to odd numbered terminals on thetest block. This ensures that when the testplug MMLB is used, the sockets in thewhite half of the plug are the isolatedrelay circuits, and the sockets in theorange half are connected to thepotentially live supplies as shown inFigure 4.

Note: It is important that thesockets in the MMLB 01 test plugwhich correspond to currenttransformer secondary windingsare shorted using external linksbefore the test plug is insertedinto the MMLG test block. For atypical example, refer to Figure 2.

This ensures that current transformersecondary windings are short-circuitedbefore they are disconnected from theprotection relay or scheme, therebyavoiding dangerously high voltages. Thisis illustrated in Figures 2 and 4.

If it is desired to use the dc auxiliarysupply during testing, then it can belinked across using the sockets in the testplug. Test equipment can be connectedto the relay or scheme using the socketsin the white area of the test plug, andoperation of contacts can be monitored.

Where more than one MMLG 01 testblock is used in the connections to arelay, it may be advisable to route the dcsupply through each of them as asafeguard against inadvertent operation.

Single-finger Test PlugThis test plug consists of two contactstrips which are insulated from eachother, and each of which is connected toa lead, as shown in Figure 6.

The test plug can be inserted intoindividual test positions in the testmodule as an alternative to the multi-finger test plug, as shown in Figure 7.This single-finger test plug allows thecurrent in any of the circuits routedthrough the test module to be monitored.

Note: An ammeter on the correctrange should be connected to thetwo leads before the plug isinserted, especially if a CTsecondary circuit is beingmonitored.

Figure 2 MMLG 01 test block and multi-finger test plug MMLB 01 (not inserted) witha CT shorting link.

Figure 3 MMLG 01 test block with multi-finger test plug MMLB 01 inserted.

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Note 1.Terminals 13 and 14 are shorted togetherby the cover contacts when the coveris in place.

1 2

3 4

5 6

7 8

9 10

11 12

13 14

15 16

17 18

19 20

21 22

23 24

25 26

27 28

MMLG 01 test block(rear view

representation)

A

B

A

B

C

P1P2

S2 S1

Trip andalarm

contactsas

required

Relay scheme

aux. supply

(See Note 1)

See Note 2

E/F

Protection scheme

C

Current injection sockets

as reqd.

Fit external linksif stationaux. supplyis required toenergise scheme.(For use withMMLG 01 only).

Equipment sideinjection/monitoring sockets(white background)

Live side sockets(orange background)

MMLB 01 test plug(front view)

2

4

6

8

10

12

14

16

18

20

22

24

26

28

1

3

5

7

9

11

13

15

17

19

21

23

25

27

See Note 2

Note 2.To avoid lethal electric shockhazard external CT terminalsmust NOT be open circuited.Shorting links must be fittedBEFORE plug insertion.

Figure 4 Typical use of MMLG 01 test block and MMLB 01 test plug.

Note 1.To avoid lethal electric shock hazardexternal CT terminals must NOT beopen circuited.Shorting links must be fitted BEFOREplug insertion.

Current injection sockets

as reqd.

Equipment sideinjection/monitoring sockets(white background)

Live side sockets(orange background)

MMLB 01 test plug(front view)

2

4

6

8

10

12

14

16

18

20

22

24

26

28

1

3

5

7

9

11

13

15

17

19

21

27

Typical connections for feeder breaker module and test block MMLG 02. For specificconnections see MBCZ external connection diagrams e.g. F10 MBCZ 12 003 sheet 3.

Mainzone CT's

See Note 1

See Note 1

1 2

3 4

5 6

7 8

9 10

11 12

13 14

15 16

17 18

19 20

21 22

23 24

25 26

27 28

MMLG 02 test block(rear view

representation)

1718192021

225

7

6

8

12

10

24

2627

28

Trip B

911

A

B

C

N

A

B

C

N

Check zone CT's

Trip

Main zone CT's

Note:DC isolation is notavailable betweenterminals 13 and 14

Trip A

Feeder Breaker ModuleMBCZ 12

See Note 1

See Note 1

Figure 5 Typical use of MMLG 02 test block and MMLB 01 test plug.

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Technical Data

High voltage withstand

Insulation

IEC 60255-5: 1977

• MMLG 01/02:

5kV rms for 1 minute between all caseterminals connected together and thecase earth terminal.

2kV rms for 1 minute between anycontact pair and either adjacentcontact pair.

5kV rms for 1 minute between anyalternate contact pair, provided thatthe intermediate contact pair is notused.

• MMLG 01 only

1kV rms for 1 minute betweenterminals 13 and 14 when the cover isremoved (eg., opening the auxiliarysupply or trip circuit).

• MMLB 01

As MMLG 01 plus

2kV rms for 1 minute betweenincoming and outgoing contacts wheninserted.

• MMLB 02

1kV rms for 1 minute between fingercontacts.

Current withstand• MMLG 01/02, MMLB 01

All contact circuits rated at 20A continuously or 400A for 1s.

• MMLB 02

Rated at 10A continuously.

Maximum working voltage• MMLG, MMLB 01

300 volts ac or dc continuous rating

• MMLB 02

300 volts ac or dc short term rating(ie. non-continuous).

Atmospheric environment• Temperature

IEC 60255-6: 1988Storage and transit –25°C to +70°COperating –25°C to +55°C

IEC 60068-2-1: 1990 Cold

IEC 60068-2-2: 1974 Dry Heat

• Humidity

IEC 60068-2-3: 196956 days at 93% RH and +40°C

• Enclosure Protection

IEC 60529: 1989

MMLG with cover fitted IP50 (dust protected)

MMLG (without cover) and MMLB 01IP20

Figure 6 Type MMLB 02 single-finger test plug.

Figure 7 Type MMLG 01 test block with single-finger test plug type MMLB 02 inserted.

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Mechanical environment• Vibration

IEC 60255-21-1: 1988: Response Class 2

EMC compliance

89/336/EECThese products have been classified aselectromagnetically benign and aretherefore excluded from the European Community EMC Directive(89/336/EEC).

• Product safety

73/23/EECCompliance with the European Commission Low Voltage Directive.

EN61010-1: 1993/A2: 1995EN60950: 1992/A11: 1997Compliance is demonstrated byreference to generic safety standards.

Mechanical Details

Test block type MMLGThe MMLG test block is a size 2 unit inthe Midos system.

Relevant sizes and panel mountingdetails are given in Figure 8.

Each terminal has:

1) A 4mm screw outlet for ‘L’ shapedpre-insulated crimp terminations.

2) Two blades (4.8mm x 0.8mm cross-section) to accept snap-on connectorsas defined in BS 5057.

Any combination of two of the abovetypes of connections may be used oneach terminal position.

An earth connection should be made tothe protective earth terminal on the rearof the MMLG using 2.5mm2 minimumwire.

If ring tabs are used for connection tothe rear terminal block, these should beof the insulated crimp type to maintaindesign insulation levels.

Multi-fingered test plug typeMMLB 01The test plug locates securely into testsockets of the MMLG test block and canbe retained by two knurled screws. Eachof the 28 test sockets of the test plugaccepts a 4mm diameter plug.

Accessories provided with each MMLB01 test plug:

4 short plug-links, each link comprisingtwo 4mm plugs joined by 50mm ofinterconnecting cable.

4 long plug-links, each link comprisingtwo 4mm plugs joined by 150mm ofinterconnecting cable.

6 spare 4mm plugs that readily acceptup to 2.5mm2 flexible insulated cable fortest-lead purposes.

Single-fingered test plug TypeMMLB 02Each plug is supplied pre-wired with asuitable length of 1.0mm2 twin flexibleinsulated cable. One core is black, andthe other red, for polarity identification.

45

177

32 21225 min.

157 max.

51

48

13

244 holes Ø4.4

168 159

Panel cut-out:Flush mounting fixing details.

All dimensions in mm.

Flush mounting.

Figure 8

Case outline size 2.

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