Tanesco Tanzania - Specification S22 Pole Mounted Autoreclosers (2002)

PECS/S22

Specification S22 - Pole Mounted Reclosers

TANZANIA ELECTRIC SUPPLY COMPANY LIMITED

SPECIFICATION S22

POLE MOUNTED AUTORECLOSERS

OCTOBER, 2002.

TANZANIA ELECTRIC SUPPLY COMPANY LIMITED

Samora Avenue, P.O. Box 9024, Dar es Salaam, Tanzania.

Telephone: +255-22-2111041/4 or 2114045/6

Facsimile: +255-22-2113836 or 2110844 or 2114981 or 2110825

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TABLE OF CONTENTS

PART 1: GENERAL

1. SCOPE............................................................................................................. S22-1

2. STANDARDS ................................................................................................. S22-1

3. SERVICE CONDITIONS ............................................................................... S22-2

4. SYSTEM CONDITIONS ................................................................................ S22-3

5. INSPECTION, TESTING AND QUALITY ASSURANCE .......................... S22-4

5.1 Inspection......................................................................................................... S22-4 5.2 Testing ............................................................................................................. S22-5 5.3 Quality Assurance............................................................................................ S22-6

6. SPARE PARTS ............................................................................................... S22-6

7. PACKING AND SHIPPING ........................................................................... S22-7

7.1 Packing ............................................................................................................ S22-7 7.2 Shipping........................................................................................................... S22-8 7.3 Hazardous Substances ..................................................................................... S22-8

8. SUBMITTALS ................................................................................................ S22-9

8.1 Submittals required with the Bid ..................................................................... S22-9 8.2 Submittals required after Contract Award..................................................... S22-10

PART 2: TECHNICAL

9. GENERAL..................................................................................................... S22-11

10. CONTINUOUS CURRENT RATING.......................................................... S22-11

11. INTERRUPTION CAPACITY ..................................................................... S22-11

12. INTERRUPTING MEDIUM ........................................................................ S22-12

13. OPERATING CHARACTERISTICS ........................................................... S22-12

14. PROTECTION CHARACTERISTICS ......................................................... S22-13

15. REMOTE CONTROL FACILITIES............................................................. S22-15

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16. SELF MONITORING FACILITIES ............................................................. S22-15

17. RADIO INFLUENCE VOLTAGE................................................................ S22-16

18. CONTROL BOX ........................................................................................... S22-16

18.1 General........................................................................................................... S22-16 18.2 Operating Mechanism.................................................................................... S22-16 18.3 Auxiliary Supply............................................................................................ S22-17

19. BASIC ACCESSORIES ................................................................................ S22-17

20. BUSHINGS AND TERMINALS.................................................................. S22-18

20.1 Bushings ........................................................................................................ S22-18 20.2 Creepage Distance ......................................................................................... S22-19 20.3 Bushing Labels .............................................................................................. S22-19

21. TANK FABRICATION ................................................................................ S22-19

22. SURFACE TREATMENT ............................................................................ S22-20

23. EARTHING TERMINAL ............................................................................. S22-20

24. MOUNTING FRAME................................................................................... S22-20

25. LIFTING EYES............................................................................................. S22-21

26. MARKINGS .................................................................................................. S22-21

27. TESTS ........................................................................................................... S22-22

27.1 Routine Tests ................................................................................................. S22-22 27.2 Type Tests...................................................................................................... S22-22 27.3 Galvanising Tests .......................................................................................... S22-23

28. SCHEDULES ................................................................................................ S22-25

28.1 Technical Data Schedule ............................................................................... S22-25 28.2 Non-Compliance Schedule ............................................................................ S22-28 28.3 Test Certificates Schedule ............................................................................. S22-29

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PART 3: INSTALLATION

29. INSTALLATION .......................................................................................... S22-30

TABLES

Table 1: Minimum Trip Current Settings ............................................ S22-14 Table 2: Functions with Remote Indication or Control ....................... S22-15

Last page .................................................................................................... S22-

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PART 1: GENERAL

1. SCOPE

This specification covers the design, manufacture, testing, supply, delivery and performance requirements of pole or ground mounted multishot reclosers for use in the networks of the Tanzania Electric Supply Company Limited, under the Power VI project.

Any departure from the provisions of this specification shall be disclosed at the time of tendering in the Non compliance schedule, in part 2 of this document.

2. STANDARDS

The equipment shall comply with the latest editions of, and amendments to, the international standards listed below. Where any provision of this specification differs from those of the standards listed below, the provisions of this specification shall apply:

ANSI American National Standards Institute: IEEE Institution of Electrical and Electronic Engineers:

ANSI/IEEE C37.60: IEEE standard requirements for overhead, pad mounted, dry

vault and submersible automatic circuit reclosers and fault interrupters for ac systems.

ASTM American Society for Testing and Materials:

A123: Zinc (hot galvanised) coatings on products fabricated from rolled, pressed and

forged steel plates, shapes, bars and stripes.

BSI British Standards Institution:

BS 729: Specification for hot dip galvanized coatings on iron and steel articles.

European Union Commission:

SI 426: European Communities (dangerous substances) (classification, packaging, labelling and notification) regulation, 1992.

IEC International Electrotechnical Commission:

IEC 56: High-voltage alternating-current circuit breakers.

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IEC 137: Bushings for alternating voltages above 1000 V.

IEC 255: Electrical relays.

IEC 376: Specification and acceptance of new sulphur hexafluoride.

IEC 437: Radio interference test on high-voltage insulators.

ISO International Organization for Standardization:

ISO 1460: Metallic coatings - Hot dip galvanised coatings on ferrous materials. Gravimetric determination of the mass per unit area.

ISO 2063: Metallic coatings - Protection of iron and steel against corrosion -Metal

spraying of zinc and aluminium.

ISO 2178: Non magnetic coatings on magnetic substrates - Measurement of coating thickness - Magnetic method.

ISO 9000: Quality management and quality assurance standards - Guidelines for

selection and use.

Associated specifications:

S01: General technical requirements of 33kV, 11kV and LV networks.

S13: Crossarms and associated steelwork.

S15: Line fittings.

S35: Bolts, nuts and washers.

The bidder may propose alternative standards, provided it is demonstrated that they give a degree of quality and performance equivalent to that of the referenced standards. Acceptability of any alternative standard is at the discretion of the employer.

3. SERVICE CONDITIONS

The service conditions shall be as follows:

altitude (above sea level) 1,600m

maximum outdoor temperature 40C

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minimum outdoor temperature 10C

maximum monthly mean temperature 35C

annual mean temperature 22C

maximum relative humidity 60% to 96%

isokeraunic level tropical

maximum wind velocity 58km/h

prevailing wind direction SE and NW

type of atmosphere coastal

Environmentally, the region where the work will take place is a coastal area, subject to an overall medium relative humidity, which can give rise to condensation. Onshore winds are frequently salt laden. On occasions, the combination of salt and condensation may create pollution conditions for outdoor insulators.

Therefore, outdoor material and equipment shall be designed and protected for use in exposed, polluted, salty, corrosive and humid coastal atmosphere.

Indoor material and equipment shall be designed and protected for use in buildings, which occasionally may be wet and damp.

4. SYSTEM CONDITIONS

The equipment shall be suitable for installation in supply systems of the following characteristics:

frequency

nominal system voltages

50Hz

33kV 11kV

400/230V

maximum system voltages: 33kV 11kV

36kV 12kV

maximum LV voltage 440/253V

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minimum LV voltage

nominal short circuit levels: 33kV

374/215V

16.5kA 11kV 25kA

insulation levels:

1.2/50s impulse (positive and negative polarity): 33kV 170kV

11kV 75kV

power frequency (one minute withstand, wet): 33kV 70kV

11kV LV

28kV 3kV

neutral earthing arrangements: 33kV 11kV LV

effectively earthed effectively earthed effectively earthed

creepage distance 30mm/kV (of maximum system voltage)

5. INSPECTION, TESTING AND QUALITY ASSURANCE

5.1 Inspection

The contractor shall submit a detailed programme covering the design, manufacture and testing of the equipment within one month of receipt of the contract award.

Reports shall subsequently be submitted at intervals, as requested by the employer or project manager, outlining progress and, if necessary, explaining deviations from the programme.

The employer or project manager shall have free entry at all times, while work on the contract is being performed, to all parts of the manufacturer's works which concern the processing of the equipment ordered. The manufacturer shall afford the employer or project manager, without charge, all reasonable facilities to satisfy himself or herself that the equipment being furnished is in accordance with this specification.

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5.2 Testing

The equipment shall successfully pass all the type tests and routine tests referred to in part 2 and those listed in the most recent edition of the standards given in clause 2 of this specification.

The employer or project manager reserves the right to reject an item of equipment if the test results do not comply with the values specified or with the data given in the technical data schedule.

Type tests shall be carried out at an independent testing laboratory or be witnessed by a representative of such laboratory or some other representative acceptable to the employer. Routine tests shall be carried out at the manufacturer's works.

Type tests may be dispensed with at the employer's discretion if the contractor furnishes evidence to the project manager's satisfaction that the relevant tests have already been performed on identical equipment. In this case test certificates shall be submitted with the bid for evaluation.

The employer shall have the tests witnessed by a representative. In order to facilitate this, the contractor shall give the project manager a minimum of four weeks notice that the material is ready for testing. If the employer or project manager does not indicate his or her intention to participate in the testing, the manufacturer shall carry out the tests and the contractor shall furnish the results thereof to the project manager.

Full details of the proposed methods of testing, including connection diagrams, shall be submitted to the project manager by the contractor for approval, at least one month before testing.

All costs in connection with the testing shall be borne by the contractor who shall provide the project manager with all the test facilities which the latter may require, free of charge. The project manager shall have the right to select the samples if he or she so desires and shall also have the right to satisfy himself or herself that the testing apparatus is correct.

The contractor shall submit to the project manager five signed copies of the test certificates, giving the results of the tests as required. No materials shall be dispatched until the test certificates have been received by the project manager and the contractor has been informed that they are acceptable.

The test certificates must show the actual values obtained from the tests, in the units used in this specification, and not merely confirm that the requirements have been met.

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The employer may decide to have the equipment inspected after reception and the project manager shall have the right to select the samples if desired. The contractor shall cooperate with this inspection and shall provide the project manager, free of charge, all the facilities which the latter may require.

In the case of components for which specific type tests or routine tests are not called for in part 2 or in the quoted standards in clause 2 of this specification, the contractor shall include a list of all tests he or she proposes the manufacturer to carry out.

5.3 Quality Assurance

The contractor shall provide current certification showing the manufacturer's compliance with ISO 9000 or equivalent national standard.

6. SPARE PARTS

The bid shall include, a comprehensive list of all consumable and non consumable spare parts and accessories, necessary for five years of normal operation as specified by the manufacturer.

In addition, the bid shall include, in price schedule 6 in section VI of these Bidding documents, a price list of recommended non consumable spare parts for all major items of equipment.

The bidder shall give an assurance that spare parts will continue to be available through the life of the equipment.

The spare parts shall be clearly identified and related to the specific equipment item. Spare parts shall be delivered suitably packed and treated for long periods in storage. Each pack shall be clearly and indelibly marked with its contents, including a designation number corresponding to the spare parts list in the operation and maintenance instructions.

All spare parts shall be stored in their respective sites and they shall be inspected and handed over to the employer after project completion. These spare parts shall not be used by the contractor under any circumstances, unless the employer is notified.

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7. PACKING AND SHIPPING

7.1 Packing

All equipment, including accessories, shall be packed and securely clamped against movement in robust, wooden, non returnable packing cases to ensure safe transit from the manufacturer's works to the work sites.

The packing shall provide suitable protection against all climatic conditions prevailing during transport and on site.

Equipment or material liable to deterioration by sea water, moisture, or ingress of foreign matter shall be totally sealed in strong polythene bags.

All accessories shall be carefully packed so that they are fully protected during transport and handling operations and in storage.

Internal surfaces of loose accessories shall be sealed off by means of gaskets and blanking off plates. Equipment and surfaces liable to deterioration due to condensation shall be protected by packs of silica gel or other approved desiccant.

Each packing case shall be indelibly marked, in two adjacent sides and on the top, with the following:

individual serial number; employer's name; contract number; contractor's name; name and address of contractor's agent in Tanzania; manufacturer's name; description of contents; country of origin; case measurements; gross and net weights in kilogrammes; and all necessary slinging and stacking instructions.

Each case shall contain a fully detailed packing list in a sealed waterproof envelope.

Five copies of each packing list shall be sent to the employer prior to dispatching the equipment.

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7.2 Shipping

The contractor shall be responsible for the shipping of all plant and equipment supplied from abroad to the ports of entry and for the transport of all goods to the various work sites and for all the costs and expenses resulting from it, including customs clearance, offloading, warehousing and insurance in accordance with appendix 3: Insurance requirements, in section VI of these bidding documents.

All transport accessories, such as riding lugs, jacking pads, blanking off plates, etc. shall become the property of the employer.

All items of equipment shall be securely clamped against movement to ensure safe transit from the manufacturer's facilities to the work sites.

All accessories shall be carefully packed so that they are fully protected during transport and handling operations and while in storage.

The contractor shall advise, if requested, the storage required for any plant and equipment that may be delivered to the employer's stores. The contractor shall be required to accept responsibility for the advice given, in so far as these arrangements may have a bearing on the behaviour of the equipment in subsequent service.

7.3 Hazardous Substances

The contractor shall submit safety data sheets for all substances used with the equipment. These substances shall be classified in accordance with the European Union SI 426: European Communities (dangerous substances) (classification, packaging, labelling and notification) regulation, 1992, or any subsequent amendment.

The contractor shall give an assurance that there are no other substances classified as hazardous in the equipment supplied. The contractor shall accept responsibility for the disposal of such hazardous substances, should any be found.

Because of the use of SF6 as the arc quenching medium bidders shall guarantee to accept the return of the reclosers when they are no longer fit for use.

The contractor shall also be responsible for any injury resulting from hazardous substances.

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8. SUBMITTALS

In addition to the documentation set out in specification S01: General technical requirements of 33kV, 11kV and LV networks, some technical documentation is required as set out in clauses 8.1 and 8.2 below

8.1 Submittals Required With the Bid

The following shall be required:

completed technical data schedule;

descriptive literature giving full technical details of equipment offered, including:

- details of permissible number of short circuit interruptions for varying values of

short circuit current;

- criteria for the end of useful life in relation to permissible contact burning and erosion of arc control devices; and

- detailed description of the recloser's operation;

outline dimension drawing for each major component, general arrangement drawing

showing component layout and general schematic diagrams;

time-current curves for reclosers in the ratings offered;

general drawing showing the recloser mounting arrangement in a single pole and a double pole line or on the ground by means of a steel frame;

detailed specification for the interrupting medium;

statement setting out the anticorrosion protection method to be used on the recloser

tank. Details of special finish applied to the recloser tank, if any, and field experience;

safety data sheets for all substances used with the equipment;

type test certificates, where available, and sample routine test reports;

detailed reference list of customers already using equipment offered with particular

emphasis on units of similar design and rating;

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details of manufacturer's quality assurance standards and programme; and

deviations from this specification. Only deviations approved in writing before award of contract shall be accepted.

8.2 Submittals Required by the Project Manager After Contract Award

The following shall be required:

programme for production and testing;

detailed assembly instructions within each packing case for each major item of

equipment;

a training video illustrating installation, operation and maintenance of the plant item; and

five bound folders with records of the technical particulars relating to the equipment.

Each folder shall contain the following information:

- general description of the equipment and all components, including brochures;

- technical data schedule, with approved revisions;

- detailed dimension drawing for all components, general arrangement drawing showing detailed component layout and detailed schematic and wiring drawings for all components;

- detailed drawing of the recloser mounting arrangement in a single pole and in a

double pole line or on the ground by means of a steel frame;

- statement drawing attention to all exposed points in the equipment at which aluminium or aluminium alloy parts are in contact with or in close proximity to other metals and stating clearly what protection is employed at each point to exclude air and moisture;

- inspection and test reports carried out in the manufacturer's works;

- detailed installation and commissioning instructions; and

- operation and maintenance instructions, as well as trouble shooting charts.

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PART 2: TECHNICAL

9. GENERAL

This specification covers the design, manufacture, testing, supply, delivery and performance requirements of 50Hz, 33kV and 11kV, outdoor, three phase, pole or ground mounted, automatic, multishot reclosers

The pole or ground mounted reclosers will be connected to the overhead lines described in specification S01: General technical requirements of 33kV, 11kV and LV networks. They shall be suitable for operation in outdoor exposed locations.

The design of the tank, fittings, bushings, interrupting mechanism and electronic control circuits shall be such that it will not be necessary to keep the reclosers energised to prevent deterioration as these units may be held in reserve, outdoors, for many years.

A small number of reclosers may be installed in locations at an altitude between 1,000m and 1,600m. The bidder shall take this into account when considering the basic impulse level and the rated maximum voltage required. A derating of the continuous current rating of the reclosers due to altitude will be acceptable but the derating factor shall be given in the technical data schedule.

10. CONTINUOUS CURRENT RATING

The 33kV reclosers shall have a continuous current rating of 50A, 100A and 200A.

The 11kV reclosers shall have a continuous current rating of 100A and 200A.

11. INTERRUPTION CAPACITY

The design short circuit levels in the employer's distribution system are:

33kV16.5kA 11kV25kA

The short circuit currents at present are well below that. Therefore the bidder shall state the maximum current making and breaking capability of the reclosers in the technical data schedule, even if those values are lower than the design short circuit levels stated above.

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12. INTERRUPTING MEDIUM

The current interrupting medium shall be sulphur hexafluoride (SF6). The interrupting medium shall conform to the standards set out in IEC 376: Specification and acceptance of new sulphur hexafluoride.

13. OPERATING CHARACTERISTICS

The operating mechanism shall consist of a device mounted internally to the recloser. Contact closing energy shall be provided by a closing solenoid, which shall also store up energy in the trip mechanism. The mechanism shall operate to open and close the three phases of the device simultaneously.

Means shall be provided to permit manual tripping, closing and lockout of the recloser locally. These operations shall be done by hand or by operating rods. The automatic recloser shall lock out after manual tripping and shall reset after manual close.

If lockout has occurred, the recloser mechanism shall only be freed by manual closing.

An operations counter shall be provided. It shall be in a location external to the equipment, where it can be read with the recloser in operation, by a person standing at ground level. The operations counter shall be protected against ingress of moisture.

A contact position indicator shall be provided with "off" indication (white letters on a green background) and "on" indication (white letters on a red background) corresponding to the open and closed position of the main contacts. It shall be in a location external to the reclosers, and where it is clearly visible by a person standing at ground level.

The recloser shall be capable of performing a sequence of up to four trips prior to lockout, even when the line fault is so close to it that the voltage at the recloser bushings is essentially zero at the instant of the trip.

Means shall be provided to enable the number of trips to be set to one, two, three or four. Means shall also be provided to enable each trip to be set individually, to either instantaneous or delayed operation.

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If upon any reclosure, normal conditions are restored on the line, the recloser shall reset after an adjustable time, and be ready for a complete new sequence of operations. This reset time shall be variable with at least the following values available: 5s, 10s, 15s and 20s. The reset timer shall not start if phase current is greater than the set minimum phase trip current.

Provision shall be made to obtain an individually adjustable time interval between each opening and closing operation. The range of dead times shall include the following 0.6s, 1s, 1.25s, 2.5s, 5s, 10s, 20s, 30s and 60s.

The selection of each dead time shall be independent and capable of being set from devices located in the control box.

An autoreclosing on/off control switch shall be provided which will switch from a mode of nominal reclosing operation to a mode of one operation to lockout.

The tripping characteristics of the single operation to lockout (when the autoreclosing is off) shall be readily set by an operator, preferably without reprogramming to either instantaneous or time delay tripping.

14. PROTECTION CHARACTERISTICS

One overcurrent device shall be provided for fault detection in each phase. In principle, the overcurrent device shall have adjustable minimum phase trip current settings at the values shown in table 1. Alternative values may be offered:

Voltage Rating (kV) Current Rating (A) Trip Current Settings (A)

33 50 20 30 40 50

33 100 30 40 60 90 100

33 200 80 100 130 150 170 200

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Voltage Rating (kV) Current Rating (A) Trip Current Settings (A)

11100 50 80 100

11200 100 130 170 200

Table 1: Minimum trip current settings

For series coil reclosers the highest value of minimum trip current shall be equal to 140% of the continuous coil rating. These coils shall be protected by fuses.

As well as phase overcurrent an earth fault current trip facility shall be provided.

The earth fault tripping levels shall be 5A, 10A, 20A, 35A, 70A, 100A, 140A and 200A.

A sequence coordination facility shall be provided which, when enabled, will coordinate between the instantaneous tripping characteristics of two reclosers in series, such that only the recloser nearest to the fault will operate.

Coordination shall be achieved by the addition of a definite time delay in the instantaneous tripping characteristics of the upline recloser. The definite time delay or constant time added shall be programmable in the range 0.01 to 9.9 sec. with increments of 0.01s.

The recloser is also required to provide selectivity with downstream fuses (NEMA standard 'K' speed fuses) protecting transformers and line branches, but only during delayed tripping operations.

An instantaneous tripping operation, with the sequence coordination facility disabled, shall result in current clearing times of less than 0.10 seconds at 1.5 times minimum phase trip current, and less than 0.05 seconds at 5 times minimum phase trip current.

A delayed tripping operation shall be characterised by control unit response time with three response time options available following characteristics A, B and C, in accordance with the relevant section of IEC 255.

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Fault indicators shall be available within the recloser control box indicating the nature of the network fault (whether short circuit or earth fault) which resulted in recloser lockout.

The selection of all variables of operation (including operating sequence, times and characteristics) shall be achieved by devices located in the control box without the need for component replacement.

15. REMOTE CONTROL FACILITIES

Table 2 shows the remote control and indication facilities which shall be provided via volt free, normally open contacts:

Function Indication Control

Recloser position yes trip/close

Autoreclosing yes on/off

Earth fault trip block yes on/off

Remote control enabling switch yes

Malfunction alarm yes

Lockout alarm yes

Table 2: Functions with remote indication or control

A remote control disable switch shall be located within the recloser control box.

16. SELF MONITORING FACILITIES

The following shall be continuously monitored and an alarm (via volt free, normally open contacts) made available in the event of a malfunction:

low auxiliary battery voltage for the protection and control circuits;

malfunction of the microprocessor controller;

failure of switching operation (such as a failure to close); and

low SF6 pressure.

Local indication shall be available detailing the nature of the fault.

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17. RADIO INFLUENCE VOLTAGE

The maximum radio influence voltage shall be 250V, measured as specified by IEC 437.

18. CONTROL BOX

18.1 General

The recloser shall be fitted with a separate control box. This control box shall be suitable for fitting on the pole at a lower level than the recloser.

The preferred method of control is electronic but bids with equipment using hydraulic control will be considered. The control box shall be capable of operating in the environmental conditions specified in clause 3.

All fittings required for mounting the control box shall be supplied. All operating parameters of the recloser, such as minimum trip current, time-current trip characteristics, reclosing and reset times, operating sequences, etc. shall be controlled from the control box. All settings shall be controlled either with positive stop selector switches or with plug in components. Ratings shall be clearly marked in relevant units of measure and no multipliers or conversions shall be required.

The insulation level of the auxiliary circuits will be as follows:

1.2/50s impulse wave: 5kV; and 1 minute, 50Hz, withstand voltage: 3kV.

18.2 Operating Mechanism

The solenoid closing coil shall be powered directly from the overhead power line to which the recloser will be connected.

The solenoid closing coil shall operate satisfactorily for 80-120% variation in rated voltage at its terminals.

An automatic changeover switch shall be available in reclosers to enable the HV closing solenoid to be energised from either side of the recloser depending on the available source.

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The tripping solenoid shall be powered from an internal battery located within the recloser control box. The tripping solenoid shall operate satisfactorily for 80-120% variation in rated voltage at its terminals.

The recloser shall have a manual trip and manual close facility at the recloser unit. Access shall not be hindered by the steel framework.

18.3 Auxiliary Supply

The auxiliary supply to the recloser control and protection circuits shall be taken from a dedicated rechargeable battery, with a dedicated battery charger. The design shall allow for the battery charger to be powered either from a 240V ac direct supply or, if that is not available, through current transformers connected to the line.

The line CTs shall be capable of delivering the energy required by a 20W control box heating unit together with the energy required by the recloser controls up to a HV line current of 10A.

19. BASIC ACCESSORIES

The following accessories shall be included in the recloser:

a means of mechanical operation, locally accessible, to use while the recloser is deenergised;

contact position indicator;

operations counter;

manual lockout lever;

manual earth fault block lever or switch;

pole or ground mounted steel frame;

a bushing metering CT with class 0.5 and burden 10va. The ratios shall be

300/200/100/50/5A for the 11kV recloser and 300/200/100/5A for the 33kV recloser;

a gas pressure gauge with red and green indication and with vandal proof protection;

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gasless type high tension bushings;

SF6 gas pressure monitoring system which will alarm (via volt free, normally open contact) in the event of low SF6 gas pressure. The SF6 gas pressure monitor shall also have the facility of inhibiting recloser operation, under network fault condition, in the event of low SF6 gas pressure;

a 9m umbilical control cable from recloser switch to control box;

full SCADA remote control and monitoring facilities;

recloser protection lockout signal via volt free, normally open contact;

recloser self monitoring facilities with volt free, normally open alarm contacts;

o automatic changeover switch for energising the closing solenoid from either side of

the recloser.

20. BUSHINGS AND TERMINALS

20.1 Bushings

The terminations shall be brought out through anti fog porcelain bushings. The bushings shall be rated to carry full line current and shall have arcing horns with spark gaps adjustable over the range of 25mm to 80mm in 11kV reclosers and 100mm to 250mm in 33kV reclosers.

The bushings shall be fitted with heavily tin plated terminals and galvanised hardware to take tin plated aluminium compression lugs.

Alternatively, the bidder may offer MOV polymeric housed surge arresters (one per HV bushing at each side of the recloser), preferably without disconnector, and included in the quoted recloser price.

In this case, the recloser shall be fitted with a means of attaching a surge arrester support bracket at either side of the recloser, consisting in brackets or extensions to the cover plate. The brackets shall be located opposite each of the HV bushings and they shall be drilled with holes having a diameter not less than 13mm for fixing the arrester brackets. The final arrester position must provide a nominal 100mm clearance between bushing and arrester. The area surrounding the mounting hole shall permit good electrical contact.

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20.2 Creepage Distance

The creepage distance of the bushings shall be 1,080mm and 360mm for 3kV and 11kV, respectively.

20.3 Bushing Labels

The bushings shall be clearly and unambiguously labelled.

The means of marking shall be either:

o engraved metal plate; or o etched anodised aluminium.

Phase identification by adhesive stickers shall not be acceptable.

If labelling is to be carried out on the tank, it is preferred that one plate be used rather than individual markings for each phase, in order to prevent incorrect phase markings.

21. TANK FABRICATION

The tank shall be perfectly sealed and dielectric fluid or vacuum tight, with all fittings in place. The head casting and the tank shall be weather proof under all operating conditions.

Furthermore, the tank shall be designed so that the completed recloser can be lifted and transported without permanent deformation, leakage or loss of vacuum. The criterion of leakage shall be discoloration by oil of whitewash applied externally to the suspected parts at an oil temperature of 90C or some other method approved by the project manager.

The tank shall be made of steel with a minimum thickness of 3mm and strong enough to support dynamic short circuit forces and the vibration of the recloser.

The head casting shall be bolted to the steel tank and neoprene seals shall be used, suitable for the temperature levels stipulated in this specification. No bolt holes shall penetrate the tank wall. Surfaces at gasketed joints shall be such that an even face is presented to the gasket, thereby eliminating the necessity for the gasket to take up surface irregularities.

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22. SURFACE TREATMENT

The tank and its accessories shall be adequately protected against corrosion and the contractor shall include a statement of the method of protection proposed.

The recloser tank shall be, preferably, hot dip galvanised, to the standards set out in BS 729, to a minimum thickness of 80m, followed by painting with a special weatherproof paint to a minimum thickness of 30m. Sufficient pretreatment of the zinc surface should be carried out as necessary in order to guarantee long life adhesion. Any small welds which may be necessary after galvanising shall be made good by treatment with zinc rich paint covered by a spray, generally matching the appearance of the tank.

The inside of the tank shall be painted with an approved oil resisting varnish or paint. The outside of the tank shall be painted grey, colour RAL 7035. The RAL colour code system is that of the DNA (German Standards Board, Frankfurt, Germany).

Where galvanising is not practical, the recloser tank may be shot blasted and then immediately zinc sprayed to an average weight deposit of not less than 550g/sq m, followed by a zinc chromate based primary paint, and two coats of durable oil and weather resisting paint. The finish colour shall be grey, colour RAL 7035.

23. EARTHING TERMINAL

All units shall be provided with an earthing terminal with a 10mm hole.

24. MOUNTING FRAME

The reclosers shall be supplied with a pole mounting frame, made of galvanised steel complying with ASTM A123, strong enough to support the vibration of the recloser.

These units may be mounted on a H frame structure with poles located at 1,830mm centres or on single poles, depending on the type of line involved. The pole mounting frame for single pole lines shall allow the centre of gravity to be as close as possible to the pole, preferably less than 330mm to allow erection with a gin.

Alternatively, the recloser shall be mounted on the ground by means of a steel frame.

It will be the contractor's responsibility to design a standard mounting arrangement. A detailed drawing shall be provided for the project manager's approval.

All steel work shall comply with the standards outlined in specification S13: Crossarms and associated steelwork.

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25. LIFTING EYES

Lifting eyes shall be provided such that the recloser can be lifted with a single hook without damage.

26. MARKINGS

Each recloser shall be fitted with a nameplate of weatherproof material, showing legibly and indelibly the following details:

o type of recloser; o standard to which it is manufactured; o manufacturer's name; o recloser serial number; o year of manufacture; o rated frequency in Hz (50); o rated voltage in kV; o Number of phases (3); o rated continuous current in A; o rated minimum tripping currents (A); o rated symmetrical interrupting current (kA); o rated symmetrical making current (kA); o 1.2/50s impulse level in kV; o power frequency withstand in kV; o rated control voltage in V; o SF6 pressure in bar; o SF6 weight in kg; o total weight in kg; and o name of the employer (Tanzania Electric Supply Company Limited).

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27. TESTS

27.1 Routine Tests

Routine tests shall be carried out in accordance with ANSI C37.60. Any item not meeting the routine test requirements shall be rejected.

The following tests shall be carried out:

o one minute dry dielectric withstand test;

o mechanical operation consisting of:

* manual operation by the trip and close levers;

* twenty five consecutive operational tests;

* four automatic operation of four trips to lockout to check sequence and time devices;

* visual and dimensional inspection; and

* minimum tripping current test; and

o galvanising tests

27.2 Type Tests

Type tests shall be carried out in conformity with ANSI C37.60, except for the radio influence voltage test which shall comply with IEC 437. Any item not meeting the type test requirement shall result in rejection of all units of that type. The employer, at his discretion, may allow the supplier to carry out repeat type tests to prove the design, but any such repeat tests shall be at the contractor's expense.

The following tests shall be carried out:

o impulse withstand test;

o power frequency voltage withstand tests;

o interruption tests;

o making current tests;

o mechanical operating duty tests;

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o minimum tripping current tests;

o temperature rise tests;

o time-current characteristic tests: data from this test shall be supplied along with the bid; and

o radio influence tests.

27.3 Galvanising Tests

The following tests, measurements or inspections shall be carried out on each of the selected samples :

o visual inspection; o thickness of galvanising coat; and o uniformity of galvanising coat.

In the event of disagreement or dispute over the results of the above tests a coating mass test shall be carried out, as set out below. The result of this test shall be definite and binding.

The visual inspection shall include the following aspects:

o smoothness: there shall be no exposed spots, spikes or anything detrimental to the

stated use of the articles or to the personnel handling them;

o stains: there shall be no acid spots, flux or dross stains;

o adhesion: there shall be no blisters, peeling or flaking. Normal handling must not give rise to deterioration;

o wet storage:storage and stacking conditions shall be appropriate. Excessive white

rust will cause the consignment to be rejected; and

o threaded items: oiled nuts with uncoated female threads, cut oversize to allow for the galvanising coating on the standard bolt threads, shall have free travel.

Thickness measurements shall be determined by a magnetic instrument method as set down in ISO 2178.

The instrument used shall have the necessary degree of accuracy, range of probes and probe adapters to enable reliable readings to be obtained consistently. Otherwise, the project manager shall nominate a suitable instrument for the purpose of obtaining the measurements.

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Before taking measurements, the instrument shall be calibrated, preferably on an ungalvanised sample of the articles under test. The steel surface used for the calibration shall be cleaned, if possible, by machine process or abrasive.

Between five and ten measurements shall be taken per sample, depending on size, shape, etc. The average thickness shall be taken to be the average of all the readings for that sample. The minimum average coating thickness shall be defined as the lowest of the individual average thickness values for the number of samples under test.

The minimum individual value of the readings taken on each sample shall be used to determine the coating uniformity.

The coating mass shall be determined by a coat stripping procedure as set down in ISO 1460.

This test, when required, shall normally be carried out on two samples. The two samples chosen shall be the ones that have given the lowest readings when tested by the magnetic measurement method.

For shaped items, details of the method of calculating the surface area shall be agreed between the contractor and the project manager.

A consignment that has been rejected may be regalvanised and again offered for test, provided that it is according to specification in all other respects.

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28. SCHEDULES

28.1 Technical Data Schedule

Description Unit Bid Type

International standard it complies with

Nominal frequency

Nominal voltage

Maximum rated voltage

Voltage correction factor for altitude

Continuous current rating

Current correction factor for altitude

Interrupting medium

Minimum Interruption Capacity: Symmetrical (rms) Assymmetrical (rms)

Minimum making current (peak)

Minimum sc trip current settings

Minimum earth fault settings

Time-current curve settings

Are response times A, B and C of IEC 255 available? (y/n)

Range of time increments to facilitate protection co-ordination

Number of time increments

Variable reclosing time settings

Resetting time settings

Maximum number of reclosures per cycle

Breaking operations between inspection of arcing contacts at rated current

Hz

kV

kV

A

kA kA

kA

A

A

s

s

s

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Description Unit Bid Breaking operations between inspection of arcing contacts at rated sc

kV

current

Voltage range of closing solenoid

Burden of closing solenoid:Current A At Voltage kV For Durations s

Type of HV Bushing

Basic Impulse Level kV

One minute, 50Hz, voltage withstand, wet kV

Clearance: Phase to Phase mm Phase to Earth mm

Minimum creepage distance mm

Minimum protected creepage distance mm

Type of surge arresters

Surge arresters rating kV

Radio influence voltage uV

Spark gap setting range mm

Is separate bushing CT available? (y/n)

Type of Control Box

Auxiliary Circuits: Basic Impulse Level kV 1 min., 50Hz withstand kV

Is changeover switch provided for closing solenoid? (y/n)

Are local manual trip and close facilities available? (y/n)

Are position indicators visible from ground? (y/n)

Is operations counter readable from ground? (y/n)

Are fault indicators for SC and EF provided in control box? (y/n)

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Description Unit Bid

How are the recloser variables entered? Are remote control facilities available? (y/n)

Is there an on/off remote control switch? (y/n)

When, off, can trip be set to delayed or instantaneous without reprogramming cycle? (y/n)

Is alarm available for:

Low auxiliary battery voltage? (y/n) Microprocessor malfunctioning? (y/n) Failure of switching operation? (y/n) Low SF6 pressure? (y/n)

Type of corrosion protection:

Recloser Tank Control Box Steel Mounting Frame

Weight (excluding SF6)

Weight of SF6

kg

kg

NB: please, fill one schedule for each type of recloser

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28.2 Non Compliance Schedule

On this schedule the bidder shall provide a list of non compliances with this specification, documenting the effects that such non compliance is likely to have on the equipment's life and operating characteristics. Each non compliance shall be referred to the relevant specification clause.

Clause No. Non Compliance

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28.3 Test Certificates Schedule

On this schedule a list of the test certificates included with the bid shall be provided. This list shall include type test certificates and sample routine test reports. Each certificate listed shall be referred to the relevant specification clause.

Clause No. Type Test Certificate or Routine Test Report

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PART 3: INSTALLATION

29. INSTALLATION

General guidelines for installation work involved in this contract are given in Specification S01: General technical requirements of 33kV, 11kV and LV networks.

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Tanesco Tanzania - Specification S22 Pole Mounted Autoreclosers (2002)

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Transcript of Tanesco Tanzania - Specification S22 Pole Mounted Autoreclosers (2002)