03-01-10-12-SN-E001 REV 0A SPEC 4 33-11KV SWITCHGEAR

Iraq Project and Contracting Office Iraq Infrastructure Reconstruction Program

SECTION - 4

SPECIFICATION FOR 33 KV & 11 KV SWITCHGEAR

03-01/10/12-SN-E001-0A Document No.

Specification for 33/11KV Substations Document Title

Sec.4, Page 1 of 33 Revision: 0A

Iraq Project and Contracting Office Iraq Infrastructure Reconstruction Program

SPECIFICATION FOR 33KV & 11KV SWITCHGEARS CONTENTS

DESCRIPTION

PAGE NO.

1.0

INTENT OF SPECIFICATION .................................................................................... 3

2.0

CODES AND STADARDS .......................................................................................... 3

3.0

EQUIPMENT AND SERVICES TO BE FURNISHED UNDER THIS SPECIFICATION 3

4.0

SITE CONDITIONS .................................................................................................... 3

5.0

DESIGN CRITERIA .................................................................................................... 4

6.0

SPECIFIC REQUIREMENTS ..................................................................................... 5

7.0

TESTS

8.0

DRAWINGS, DATA & MANUALS ............................................................................. 11

9.0

SPARES

.................................................................................................... 10

..................................................................................................... 12

10.0 ANNEXURE-A: RATINGS AND REQUIREMENT ..................................................... 13 11.0 ANNEXURE-B: BILL OF MATERIALS...................................................................... 15 12.0 ANNEXURE-C: TECHNICAL PARTICULARS .......................................................... 18

03-01/10/12-SN-E001-0A Document No.

Specification for 33/11KV Substations Document Title

Sec.4, Page 2 of 33 Revision: 0A

Iraq Project and Contracting Office Iraq Infrastructure Reconstruction Program

SPECIFICATION FOR 33KV & 11KV SWITCHGEARS 1.0

INTENT OF SPECIFICATION This specification is intended to cover the design, manufacture, assembly, testing at manufacturer's works, supply & delivery, properly packed for transport of 33kV Switchgear & 11kV Switchgear complete with all accessories and auxiliary equipment for efficient and trouble-free operation.

2.0

CODES AND STADARDS The equipment to be furnished under this specification shall, unless otherwise stated, be designed, constructed and tested in accordance with the applicable sections of the latest revision of relevant International Electrotechnical Commission (IEC) publication.

3.0

EQUIPMENT AND SERVICES TO BE FURNISHED UNDER THIS SPECIFICATION

3.1

Two(2) sets of 33 kV Switchgear Line-up as per Single Line Diagram.

3.2

One (1) set of 11 kV Switchgear Line-up as per Single Line Diagram.

3.3

One(1) set of earthing truck for 11 kV bus side earthing.

3.4

Spare parts.

3.5

All relevant drawings, data and instruction manuals.

4.0

SITE CONDITIONS For the purpose of equipment design, the following data shall be taken into consideration: Site elevation above mean sea level

:

≤ 1000m

Ambient air temperature §

Highest max (in shade) for about 6 hours a day

:

55°C

§

Lowest minimum

:

(-)10°C

§

Max yearly average

:

(+)30°C

§

Max daily average

:

(+)40°C

§

Maximum relative humidity

:

92% at 40°C

§

Seismic zone

:

(data not available)

03-01/10/12-SN-E001-0A Document No.

Specification for 33/11KV Substations Document Title

Sec.4, Page 3 of 33 Revision: 0A

Iraq Project and Contracting Office Iraq Infrastructure Reconstruction Program §

Sand storm storm

:

Subjected to strong and frequent sand

5.0

DESIGN CRITERIA

5.1

The 33kV & 11kV switchgears will be used to supply power to various distribution circuits, as well as nearby localities through 33kV & 11kV line feeders & transformer feeders.

5.2

The switchgears will be located indoors in a clean but hot, humid and tropical atmosphere.

5.3

For continuous operation at specified ratings, temperature rise of the various switchgear components shall be limited to the permissible values stipulated in the relevant standards and/or this specification.

5.4

The switchgears and their components thereof shall be capable of withstanding the mechanical forces and thermal stresses of the short circuit current of the system without any damage or deterioration of material.

5.5

Each substation will have two (2) 33kV Incomer circuit breakers. Before each circuit breaker, one set of 3-phase off-load Isolator will be provided for isolation and ease of maintenance. These Isolators will be mounted inside panels and mechanically interlocked with corresponding Circuit Breakers so that isolators could not be operated when the breaker is in Service. Breakers will have built-in earthing arrangement. As soon as the breakers are withdrawn, corresponding cable terminals will be earthed. Rating of the isolators will be same as the breaker. These two breakers will directly feed power to HV sides of two 33/11.5kV transformers. The 11kV switchgears shall have two incoming and one bus-coupler circuit breaker feeders. Each incoming feeder shall be rated to feed entire load of the switchgear. Under normal condition, two incoming feeders of the switchgear shall operate independently with bus coupler open. There shall be provision for manual/auto changeover of the supply from one incomer to the other through trip selector switch and under voltage relays. In addition provision shall be made to run both the source in parallel at 11 kV.

5.6

The ratings of all equipment including bus bars of the switchgears shall be as shown in the attached single line diagrams. Each incoming feeder shall be rated to carry continuously 110 percent of rated secondary current of the transformer feeding the switchgear. The rating of the bus coupler feeder shall be equal to the rating of the incoming feeder.

5.7

11kV outgoing breakers shall be suitable for switching oil filled type L.T. transformers both under loaded and unloaded conditions as well as feed power through long lines (partially cables & OHL conductors). When switching inductive and capacitive currents, the over voltages produced on any switching duty shall be less than 2.5 p.u. Where the switching over voltages exceed 2.5 p.u., the manufacturer shall provide appropriate metal oxide surge arresters on both cable and bus bar sides of the circuit breaker, on each circuit to protect the system at no extra cost to the customer. These surge arresters shall be mounted inside the panel.

5.8

Equipments, accessories and devices covered in this specification shall meet the requirements of the referenced IEC or other international standards.

5.9

Provisions shall be made for padlocking the circuit breakers in the test and disconnect positions.

03-01/10/12-SN-E001-0A Document No.

Specification for 33/11KV Substations Document Title

Sec.4, Page 4 of 33 Revision: 0A

Iraq Project and Contracting Office Iraq Infrastructure Reconstruction Program 5.10

The low voltage section shall be arranged with a barrier so that it can be entered with the contactor energized without exposing personnel to high voltage.

5.11

33 kV & 11 kV switchgears shall be suitable for withstanding internal arc faults in line with IEC 60298, Clause 5.101.4.

5.12

The switchgear shall be designed for a service life of at least 30 years in the environment for the duty specified on the data sheets.

6.0

SPECIFIC REQUIREMENTS

6.1

Construction

6.1.1

The switchgear panels shall be indoor, metal-clad, floor mounted, drawout type. Design and construction shall be such as to allow extension at either end.

6.1.2

The switchgear enclosure shall conform to the following degree of protection as per IEC 60529: For covers

:

IP33

For bus bar, cable and breaker

:

IP 54

For instruments

:

IP50

The minimum thickness of sheet steel used shall be 2 mm. 6.1.3

The switchgear assembly shall comprise of a continuous, dead-front, line-up of free standing, vertical cubicles. Each cubicle shall have a front-hinged door with latches and a removable bolted back cover. All covers and doors shall be provided with neoprene gaskets. Each cubicle shall have suitable lifting device.

6.1.4

Switchgear cubicle shall be so sized as to permit closing of the front access door when the breaker is pulled out to TEST position. The working zone at the front of cubicle shall be restricted within 750 mm to 1800 mm from floor level.

6.1.5

Circuit breakers, instrument transformers, bus-bars, cable compartment etc., shall be housed in separate compartments within the cubicle. The design shall be such that failure of one equipment shall not affect the adjacent units.

6.1.6

All relays, meters, switches and lamps shall be flush mounted on the control cabinet built on the front of the cubicle.

6.1.7

For easy maintenance, the width of the panel shall not be less than 800mm.

6.2

Bus and Bus Taps

6.2.1

The main buses and connections shall be of copper, sized for specified current ratings with maximum temperature limited to 90°C (including ambient of 40OC).

6.2.2

Busbars and connection shall be fully insulated for working voltage with adequate phase/ground clearances. Insulating sleeves for busbars and cast-resin shrouds for all joints and tap-offs shall be provided. Bus support insulator shall be flame-retardant, track resistant type with high creepage surface.

03-01/10/12-SN-E001-0A Document No.

Specification for 33/11KV Substations Document Title

Sec.4, Page 5 of 33 Revision: 0A

Iraq Project and Contracting Office Iraq Infrastructure Reconstruction Program

6.2.3

All buses and connections shall be supported and braced to withstand stresses due to maximum short circuit current and also to take care of any thermal expansion.

6.2.4

Busbars shall be colour coded for easy identification and so located that the sequence R-Y-B shall be from left to right, top to bottom or front to rear, when viewed from front of the switchgear assembly.

6. 2.5

The busbar chamber shall be provided with interpanel barrier with epoxy cast seal-off bushings through which the buses will pass through so as to prevent propagation of fire from one panel to another.

6.3

Circuit Breaker

6.3.1

Circuit breakers shall be triple pole, single throw, Vacuum type.

6.3.2

Circuit breakers shall be drawout type, having SERVICE, ISOLATED and EARTHED positions with positive indication for each position.

6.3.3

All 33 kV and 11 kV circuit breakers shall have motor wound spring charged trip free mechanism with antipumping feature, with provision for high speed auto-reclosing and shunt trip. In addition, facility for manual charging of spring at any breaker position shall be provided.

6.3.4

For motor wound mechanism, spring charging shall take place automatically after each breaker closing operation. One open-close-open operation of the circuit breaker shall be possible after failure of power supply to the motor. A visual mechanical indicating device will also be provided to show the position of the spring.

6.3.5

Interlock arrangements shall be as stated in clause 5.11 of IEC 62271 – 200. Mandatory interlocks shall be mechanical Mechanical safety interlock shall be provided to prevent : a)

The circuit breaker from being racked in or out of the service position when the breaker is closed.

b)

Racking in the circuit breaker unless the control plug is fully engaged.

6.3.6

Automatic safety shutters shall be provided to fully cover the female primary disconnects when the breaker is withdrawn.

6.3.7

Each breaker shall be provided with an emergency manual trip, mechanical ON-OFF indication, an operation counter and mechanism charge/discharge indicator.

6.3.8

Control voltage shall be 110V DC.

6.3.9

Breakers shall be suitable for high speed auto reclosing capbility

6.4

33kV Isolator

6.4.1

Isolators shall be panel mounted, triple pole, single throw, air insulated, load-break type.

6.4.2

All other details of the panels will be identical to that circuit breaker panels.

03-01/10/12-SN-E001-0A Document No.

Specification for 33/11KV Substations Document Title

Sec.4, Page 6 of 33 Revision: 0A

Iraq Project and Contracting Office Iraq Infrastructure Reconstruction Program 6.4.3

Isolators shall be mechanically & electrically (wherever possible) interlocked with circuit breakers in order to avoid operation of Isolators when the CB is closed.

6.4.4

Each breaker will be provided with suitable cable side earthing truck or built-in earthing arrangement.

6.5

Control & Indication The circuit breaker shall be wired up for local & remote operation through SCADA system. Each breaker cubicle shall be equipped with following :

6.5.1

One control cabinet, mounted on top of breaker cabinet, provided with suitable anti-vibration facilities. One (1) TEST-NORMAL and LOCAL-REMOTE stayput type selector switch with pistol grip handle and key interlock.

6.5.2

Two (2) heavy duty oil tight, push buttons for TRIP & CLOSE. TRIP Push button shall be shrouded type to prevent accidental operation.

6.5.3

Nine (9) indicating lights on front of compartments : GREEN RED AMBER WHITE BLUE RED & GREEN YELLOW & BLUE

: : : : : : :

Breaker Open Breaker Closed Auto Trip Spring charged Trip Circuit Healthy Earth Switch Closed & Open Breaker Test & Service Position

6.5.4

Lamps shall be low watt LED Cluster type. Lamp and lens shall be replaceable from the front.

6.5.5

A common audible alarm for each switchgear line-up shall be provided to alert the operator that circuit breaker has tripped. Means shall be provided for silencing the audible alarm whilst leaving it free to sound when any other alarm is initiated but the associated alarm indications shall continue until cancelled.

6.6

Current Transformer

6.6.1

Current transformers shall be cast resin type. All secondary connections shall be brought out to terminal blocks where wye or delta connection will be made. The CT secondary shall be rated for 1A (for relays) and 5A (for metering).

6.6.2

Accuracy class of the Current Transformers shall be :

a)

Class PX for differential relaying.

b)

Class 5P20 for other relaying

c)

Class 1.0 and ISF