3BHS125149 E50 RevB ACS 5000 MCB Specification.pdf

We reserve all rights in this document and in the information contained therein. Reproduction, use or disclosure to third parties without express authority is strictly forbidden. © ABB Switzerland Ltd

Issued Dietmar Gamp 1.12.2008 Technical Specification MCB No. of sh.

Check / rel. Thomas Bächle 1.12.2008 8

Resp. dept. ATDAD MCB Specification for ACS 5000

Document No. Lang. Rev. ind. Sheet

ABB Switzerland Ltd 3BHS125149 ZAB E50 en B 1

ACS 5000

Main Circuit Breaker

Specification

Document No. Lang. Revision Sheet


Revisions Index Page/Chapter Description Date/Name

- All First issue 20.03.2006 / Ga

A 3.1.5

3.2.5.1 Fig. 3 to 6

CTs on transformer primary side Revised description of undervoltage coil Revised drawing

10.08.2006 / Ga

B all Complete revision 01.12.2008 / Ga

Table of Contents

1 Purpose of this Document..............................................................................................3

2 Overview ..........................................................................................................................3

3 Circuit Breaker Main Technical Data .............................................................................3 3.1 Voltage and Current Ratings.............................................................................................3 3.2 Total break Time ...............................................................................................................3

4 Signal Interface between Drive and Main Circuit Breaker...........................................4 4.1 Overview of Control Signal Interface.................................................................................4 4.2 MCB Control Signals .........................................................................................................5 4.2.1 Contact Ratings of the MCB Control Signals .............................................................5 4.3 MCB Status Feedback Signals..........................................................................................6

5 MCB Control Principles ..................................................................................................6 5.1 Release Conditions for Closing.........................................................................................6 5.2 MCB in Test Position.........................................................................................................6 5.3 MCB in Service Position....................................................................................................7 5.4 MCB Opening Circuit.........................................................................................................7 5.4.1 Opening Circuit with Undervoltage Coil......................................................................7 5.4.2 Opening Circuit with Two Opening Coils ....................................................................8



1 Purpose of this Document

This document specifies the technical requirements for the Main Circuit Breaker (MCB) of an ACS 5000 variable frequency drive system.

Additional customer, application or site specific requirements may be applicable, but shall not be in contradiction to the requirements listed in present document. In case of such contradictions this specification shall prevail. Deviations from this specification require approval by ABB.

2 Overview

The MCB is located on the primary side of the converter transformer. The MCB connects and disconnects the main power to the ACS 5000 drive system and protects the system against subsequent damages originating from failures on MV supply side (e.g. overvoltage), in the converter (e.g. failed components) or in any other component of the drive system.

The MCB shall preferably be a SF6-gas insulated or a vacuum-type circuit breaker.

For safe and reliable operation, it is imperative that the MCB is exclusively closed by the ACS 5000 and that the requirements, stipulated in this specification, specifically for the break time and the signal interface of the MCB, are adhered to.

3 Circuit Breaker Main Technical Data

3.1 Voltage and Current Ratings

The rated voltage of the MCB shall be equal or higher than the nominal voltage of customer’s MV supply network.

The current ratings of the MCB must be sufficient

• to make and carry nominal load currents (incl. specified overload conditions) of the drive system,

• to clear short-circuit currents in the drive system (i.e. transformer, converter and cabling), incl. transformer primary side short-circuit current.

3.2 Total Break Time

The maximum total break time of the MCB must not exceed 60 ms.

Remark: For converter protection reasons the maximum response time for opening the MCB shall not exceed 75 ms. This requirement is fulfilled with above specified break time and a maximum signal delay time inside ACS 5000 controls of less than 15 ms.



4 Signal Interface between Drive and Main Circuit Breaker

4.1 Overview of Control Signal Interface

The following diagram shows the principal signal interface between the ACS 5000 control system and the MCB.

MCB order close

MCB order open 1

MCB order open 2 (1*)

MCB

MCB status closed

MCB status open

MCB available

MCB order trip (2*)

-Q0

Feeder Protection

Relay

-F1

-Q5

DO

DI

Motor M

ACS 5000

Transformer

MV - Switchgear

3*)

4*)

4*)

-F2

Con

verte

r co

ntro

l sys

tem

Frequency converter

Transformer Protection Relay

Figure 4-1 Signal Interface

Remarks: (1*) / (2*) Either command “MCB Order Open 2" or “MCB Order Trip“ shall be used to open the MCB by a 2nd signal.

3*) CTs on each transformer primary system are required because they allow a more selective overcurrent protection.

4*) Depending on the number of available current input circuits one, two or three protection relays are required.



4.2 MCB Control Signals

As shown in Figure 4-1, the “MCB Order Open” and “MCB Order Close” signals are active high pulse signals, i.e. the control relay contacts close to activate the command. The “MCB Order Trip” signal is active low (steady state), i.e. the relay contact opens to activate the command.

The MCB open command shall be redundant using either:

• “MCB Order Open 1” and “MCB Order Trip” or

• “MCB Order Open 1” and “MCB Order Open 2”

The MCB shall open instantaneously, as soon as one or more of the open / trip commands are received.

The requirement for two open commands is based on the following standards:

• ISO 13849-1 Safety of machinery – Safety-related parts of control systems – Part 1: General principles for design The standard states the following in section 6.2.6 Category 3: “SRP/CS (safety-related parts of control systems) of category 3 shall be designed so that a single fault in any of these parts does not lead to the loss of the safety function”.

• IEC 60204-1 Safety of machinery – Electrical equipment of machines – Part 1: General requirements The standard states the following: “By providing partial or complete redundancy, it is possible to minimize the probability that one single failure in the electrical circuit can result in a hazardous situation. Redundancy can be effective in normal operation (on-line redundancy) or designed as special circuits that take over the protective function (off-line redundancy) only where the operating function fails”.

For reliability and safety reasons it is recommended (even essential without undervoltage tripping coil) that the MCB control voltage is tapped from a save supply system (UPS).

4.2.1 Contact Ratings of the MCB Control Signals

The contact ratings of the auxiliary relays in the ACS 5000 control cabinet are as follows: Table 4-1 Contacts for MCB Open / Close / Trip Commands

Auxiliary Voltage (supplied from MCB)

Max. Breaking Current *

≤ 30 VDC 6.0 A

≤ 110 VDC 2.4 A

≤ 220 VDC 0.5 A

380 VAC 6 A

* The above listed current ratings are valid for inductive load.



4.3 MCB Status Feedback Signals

As shown in Figure 4-1, the MCB shall offer the following status feedback signals to the ACS 5000 converter controls:

• A dry contact indicating “MCB status closed”

• A dry contact indicating “MCB status open” – recommended signal, but not mandatory

• A dry contact indicating “MCB available” – recommended signal, but not mandatory This signal shall indicate that the MCB is ready for operation, i.e. not in test position, no alarm or trip present and in remote control mode.

5 MCB Control Principles

5.1 Release Conditions for Closing

Release conditions for closing the MCB are typically:

• Grounding switch of the MV switchgear, if applicable, is open.

• MCB is racked-in, i.e. in service position.

• Control voltage available.

• No disturbance / alarm present, no trip / lock-out active.

• Control voltage available.

It is recommended to combine those conditions for the summary status signal “MCB available”, as specified in the previous chapter.

5.2 MCB in Test Position

Note: When in “test” position, it is assumed that the MCB is isolated (racked-out) from the feeding MV bus system.

Control switches, selector switches and status indication shall be provided on the door of the switchgear cabinet.

The selector switch shall provide two positions, one for “local” and one for “remote”.

When the MCB is in “test” position, the MCB can be closed either from the local pushbutton or from remote depending on the position of the selector switch.

When the selector switch is in “remote” position, it shall be possible to test all interlocks. Therefore all MCB indications and interlock functions shall remain operative.

When the selector switch is in “local” position, it shall be possible to close the MCB at any time. Therefore, no interlock function shall remain active.



5.3 MCB in Service Position

Note: When in “service” position (i.e. in normal operation mode), it is assumed that the MCB is connected (racked-in) to the feeding MV bus system.

When the MCB is in “service” position and the selector switch is in “remote” position, closing of the MCB shall be possible exclusively from ACS 5000 control.

When the selector switch is in “local” position, closing the MCB shall not be possible. Note: Uncontrolled closing of the MCB, while the MCB is in service position, could cause danger to life or severe damages to the drive system.

All interlock and protection functions shall remain operative at any time.

Opening of the MCB shall be possible at any time independent of the position of the selector switch.

5.4 MCB Opening Circuit

Besides its standard opening coil (YO 1), the MCB shall additionally either be equipped with an undervoltage coil (YU) in the control circuit or with a second opening coil (YO 2). Which design shall be used, has to be agreed between buyer and supplier.

5.4.1 Opening Circuit with Undervoltage Coil

A typical set-up, using one opening coil and one undervoltage coil, is shown in following diagram.

-YO 1(OFF)

A1

A2

MCBControlSupply

ACS 5000MCB

-Q0

internal trip signals

externaltrip signals

-YU(undervoltage coil)

A1

A2


MCB order open 1 MCB order trip

U<

contact closed --> MCB "OFF" command

contact open --> MCB "Trip" command

local OFF pushbutton

OFF main contacts of MCB (-Q0)

Figure 5-1 MCB Control Circuit with Undervoltage Coil



Usually, the undervoltage trip release is a solenoid which is normally energized and then trips the MCB by a spring mechanism when the voltage drops below a specified threshold. Typically, the device should not trip the MCB when the voltage is above 60 -70% of rated voltage but should trip the MCB when the voltage is less than 40%. The MCB can be closed again when the control voltage is above 85% of its rated value.

The undervoltage trip release is a safety and protection feature and shall not be used for switching during normal operation. In the event of an undervoltage in the auxiliary supply, the undervoltage coil YU is de-energized and the spring which opens the MCB is released.

5.4.2 Opening Circuit with Two Opening Coils

A typical alternative set-up, using two opening coils, is shown in following diagram. If no undervoltage coil is used it is essential that the MCB control voltage is tapped from a safe supply system (UPS) in order to guarantee opening of the MCB under all circumstances.

As shown in the diagram below, it is additionally suggested (but not mandatory) to supply the opening coils from two different supply systems in order to minimize common dependencies. In this case the voltage ratings of the two opening coils have to be determined individually.

-YO 1(OFF)

A1

A2

MCBControl

Supply 1

ACS 5000MCB

-Q0

internaltrip signals


A1

A2



MCB order open 1 MCB order open 2

-YO 2(OFF)

ontact closes --> MCB "OFF" command

contact closes --> MCB "OFF" command

local OFF pushbutton

OFFmain contacts of MCB (-Q0)

MCBControl

Supply 2

Figure 5-2 MCB Control Circuit with Two Opening Coils

3BHS125149 E50 RevB ACS 5000 MCB Specification.pdf

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