Section 3 h.v Switchboard and Related Equipment

SECTION 3 H.V SWITCHBOARD AND RELATED EQUIPMENT

MC 3 T TRUNG TH V CC THIT B LIN QUAN

J. Roger Preston Vietnam Co., Ltd SECTION 3 H.V SWITCHBOARD AND RELATED EQUIPMENT MC 3 T TRUNG TH & CC THIT B LIN QUAN

The English language version prevails u tin s dng ting Anh khi c tranh chp SECTION 3/VISTA VERDE SPECS/ ELECT 3/1

3.1 GENERAL

This part of the Specification covers the design, fabrication, delivery, installation, testing and commissioning of high tension switchgear and switchboards to be supplied and installed by the Sub-Contractor.

The Sub-Contractor shall note that this Specification is based on sulphur hexafluoride (SF6) switchgear. The Sub-Contractor may offer vacuum switchgear as an alternative provided that the space requirements are complied with. In this case, full technical specification of the proposed switchgear shall be submitted by the Sub-Contractor to the Engineer for consideration.

The H.V. switchgear shall be rated at min. 400 amp, 24 kV indoor single busbar, air-insulated, metal-clad SF6 or Vacuum type.

Type-test certificates of the circuit breaker and switchboards shall be submitted with the Tender. The results of all type tests shall be recorded in type-test reports containing sufficient data to prove compliance with the Specification. Complete details of type tests shall be submitted for inspection when requested by the Engineer during tender assessment. Appropriate technical information and literature in English language must be submitted with the Tender. Type-test certificates shall be issued preferably by the Association of Short-Circuit Testing Authorities (ASTA). Test certificates issued by other organisations will only be accepted if the testing authority is established as being of equal standing as ASTA.

3.2 RATING

The ratings of the switchgear shall be as follows:-

Rated voltage : 24 kV 3 Phase

No. of poles : Three

3.1 TNG QUT

Phn ny cp r v thit k, nh sn xut, vn chuyn, lp t, kim tra, v thm nh cc thit b ng ct v chuyn mch cao th c cung cp v lp t bi nh thu.

Nh thu s ch rng c im k thut ny ca my chuyn mch ny da trn my ct bng hp cht sulphur hexafluoride (SF6). Nh thu c th s dng my ct chn khng thay th nhng phi m bo khng gian yu cu. Trong trng hp ny, nhng c im k thut ca my c thay th s c xem xt bi Qun l K thut.

My ct cao th s c gi tr thp nht l 400 amp, 24kV trn mt thanh ci, loi cch ly chn khng, lp kim loi SF6 hay loi chn khng.

Giy chng nhn kim nh ca CB v my ct s c trnh cng vi gi thu. Tt c cc kim tra s ghi nhn y cc thng s trong bin bn kim tra xc nhn ng cc ch tiu. Ton b nhng chi tit kim tra s c trnh ln Qun l K thut thm nh khi c yu cu trong qu trnh m thu. Thng tin k thut v ti liu bng Anh ng phi trnh cng vi gi thu. Giy chng nhn kim tra tt nht l c cp bi Hi ng kim nh Association of Short-Circuit Testing Authorities (ASTA). Giy chng nhn cp bi t chc khc ch c chp nhn nu kim tra bi c quan c thm quyn theo tiu chun tng ng ASTA.

3.2 THNG S NH MC

Nhng gi tr ca my ct s tun theo cc thng s nh sau:

in p nh mc : 24 kV 3 Phase

S cc : Three



Rated frequency : 50 Hz Rated impulse withstand voltage to earth and between poles : 125 kV

Rated one minute power frequency withstand voltage to earth and between poles : 50 kV

Rated current of circuit breaker : 400/630 A

Rated current of busbar : 630 A

Short circuit rating : 25 kA/ 3 sec.

Making capacity : 62.5 kA

Breaking capacity : 25 kA R.M.S.

Both the short-circuit rating, making capacity and breaking capacity, shall apply when the circuit-breaker is being closed in the "SERVICE" location and also with the equipment arranged for busbar earthing and for circuit earthing.

The panel shall be a dust and damp protected enclosure to IP5X (BS EN 60529: 1992 - Specification for degrees of protection provided by enclosures (IP code)).

3.3 SWITCHGEAR PANEL DESCRIPTION

The switchboard shall include the current transformers, voltage transformers, indicator lamps, ammeters, voltmeters, interlocks and protection equipment as shown on the drawings and described in the Specification.

3.4 ACCESSORIES

The Sub-Contractor shall supply and install the following items complete with any other accessories necessary for the safe and proper operation of the switchboard:-

a) One set of H.V. test plugs for injection test through the six orifices of the circuit breaker.

b) One set of H.V. test plugs for primary

Tn s : 50 Hz in p xung kch chu c gia pha vi t : 125 kV

in p tn s nh mc gia in p v ni t v gia cc cc chu ng trong 1 pht : 50 kV

Dng nh mc ca CB : 400/630 A

Dng nh mc ca thanh ci : 630 A

Dng ngn mch nh mc : 25 kA / 3 sec.

Kh nng ng (nh) : 62.5 kA

Kh nng ct ngn mch : 25 kA R.M.S.

C hai gi tr dng ngn mch, dung lng ng v ct mch s c tnh khi CB ang v tr hot ng SERVICE v s lp t cc thanh ci ni t v mch ni t cng vy.

T in phi c bo v chng bi v m t theo IP5X (BS EN 60529: 1992 - Specification for degrees of protection provided by enclosures (IP code)).

3.3 T CHUYN MCH TRUNG TH

T chuyn mch gm c bin dng , bin p, n bo pha, ng h o dng, o p, kho lin ng v cc thit b bo v nh trong bn v v c m t trong tiu chun k thut.

3.4 CC THIT B , PH TNG I KM

Nh thu s cung cp v lp t ton b nhng hng mc sau cng vi nhng thit b cn thit khc t in hot ng an ton v chnh xc.

a) Mt b kim tra in p cao cho kim tra phun thng qua su ci l ca CB.

b) Mt b kim tra cao p cho kim tra p ng



injection through the V.T. orifices.

c) One set of padlocks each with three keys for each padlocking point.

d) One key cabinet for padlocks and keys.

e) Other necessary miscellaneous items such as heaters, fuses and fuse links for tripping protection, terminal board tag blocks etc.

The Sub-Contractor shall supply and install any additional relays, contactors, wiring, fuses, M.C.Bs, wiring termination etc. in the switchboard supplied to ensure the proper and safe operation of the switchboard.

The switchboard shall be assembled to form a complete flush fronted switchboard and readily extensible at either end.

3.5 GENERAL CONSTRUCTION

The switchboard shall consist of dust and vermin-proof cubicles segregated into single tier compartments. It shall be made from sheet steel of 2mm minimum thickness. The switchboard shall be suitable for all normal and fault conditions and is to withstand repeatedly without distortion or failure, shocks caused by closing and opening of the circuit breaker.

Each switchgear unit shall comprise two main portions, a fixed portion housing the busbars, current transformers, voltage transformers, relays, indicating lamps and instruments and a moving portion comprising a carriage complete with SF6/ vacuum circuit breaker.

A relay and instrument compartment shall be located at the front of the switchgear unit and a hinged door shall be provided for access to the internal wiring and terminals. Moulded gaskets of non-aging material shall be used to provide close sealing. The height of the instrument panel above floor level shall not exceed 1800mm. All panels constituting a complete switchboard shall

s b thng qua nhng ng V.T.

c) Mt b kho mc vi mi 3 chic cho mi im kho.

d) Mt t ng v cha kho.

e) Nhng thit b khc nh in tr, cu ch, b ng ct cu ch,v.v

Nh thu s cung cp v lp t nhng rle ph, contactor, dy, cu ch, MCBs, u ni dy v.v c cung cp t in hot ng an ton v chnh xc.

T in s c lp t thnh mt dy lin pha trc v c khong trng hai u c th m rng thm.

3.5 CU TO CHUNG

T s c mt bung cch ly chng li bi v cn trng c xp lng vo nhau. N c lm t tm thp c dy ti thiu l 2mm. T phi thch hp trong tt c cc iu kin bnh thng v khi c s c v khng b bin dng, hay h hng, sc khi ng ct CB.

Mi my ct gm hai phn chnh, phn v c nh v thanh ci, bin dng, bin p, rle, n bo pha, v cc thit b khc; phn di ng bao gm b chuyn mch vi my ct chn khng SF6.

Ngn ng dng c v rle c t pha trc t v ca c lp bn l m vo ni t dy v ni dy bn trong. m ca c lm t vt liu khng lo ho. Chiu cao ca t so vi mt sn khng vt qu 1800mm. Tt c t in c chiu cao ngang bng nhau. Cht ca np trn v sau c thit k d dng thao tc trong tng t ring r m khng cn m nhng ni ang c in khc.



be equal height. Bolted-on rear and top covers shall be designed to gain access to individual circuits without exposing other circuits which may be live.

All steel metalwork must be treated to prevent rusting and shall be complete with polyester powder paint finish. The colour of the panel finish shall be manufacturers standard. Instruments and relays shall be finished in black. A continuous earth bar shall run along each board for the efficient earthing of all sections.

3.6 SWITCHBOARD LAYOUT

The Sub-Contractor shall ensure that sufficient space shall be available for both front withdrawal of circuit breakers and rear termination of power cables.

A rubber insulating mat of 1m wide in switchboard length and 3mm thick, complying with BS 921, shall be provided in front of the switchboard panels.

3.7 BUSBARS AND CONNECTION

Busbars and connections of a cubicle shall be of copper in accordance with BS 159: 1992 - Specification for high-voltage busbars and busbar connections and BS 1977: 1991 - Specification for high conductivity copper tubes for electrical purposes in respect of current rating and material analysis.

Primary busbars shall be contained in a separate compartment within the switchboard and access shall be possible only by means of bolted-on sheet steel covers which shall be clearly marked "BUSBARS". Busbars and busbar connections shall not be exposed when covers and doors are open for access to the remainder of the switchgear. Busbars shall be readily extensible.

Each phase conductor of the primary busbars, including all through joints and tapping connections shall, in addition to being spaced at

Tt c tm kim loi phi c s l chng r st v c sn bng bt polyester. Mu sn s l mu ca chnh hng. Cc thit b v rle s hon ton l mu en. Thanh ci ni t s chy dc mi t ni t an ton cho tng phn.

3.6 S SP T T CAO P

Bn thu phi m bo khng gian mt trc CB c ko ra d dng v mt sau t u ni cp.

Theo BS921, mt tm thm cao su cch in c chiu rng 1m s tri di theo mt trc t in v c b dy 3mm.

3.7 THANH CI V U NI

Thanh ci v s u ni trong mt t phi tun theo BS 159: 1992 - Specification for high-voltage busbars and busbar connections and BS 1977: 1991 - Specification for high conductivity copper tubes for electrical purposes t bit i vi gi tr dng in v cht liu u ni.

Nhng thanh ci chnh s t trong mt ngn ring bit trong t in v ch c th tip cn c qua tm thp che bt bulong v c dn cnh bo BUSBAR. Thanh ci v u ni s nhn thy c khi np che v ca m ra tip cn nhng phn cn li trong t. Thanh ci phi c th ko ra mt cch d dng.

Mi pha ca thanh ci chnh, gm tt c nhng im u ni t u n cui v b ni ly ngun s lm tng thm khong cch cho khong trng



such intervals as to give the necessary air clearance for the voltage rating, be completely insulated or epoxy encapsulated in an approved manner. Taping will not be accepted.

Primary busbars, connections and their supports shall be of an approved type and shall be capable of carrying the short-time current associated with their short-circuit ratings for a period of 3 seconds.

Where busbar supports use insulation of moulded or resin-bonded material, it shall have a durable anti-hygroscopic surface finish with high anti-tracking properties.

The connections from busbars in individual units shall have a continuous current rating of not less than that of the equipment comprising the unit.

At all points when connections or joints occur, the busbars and connecting pieces shall be tinned or silver-plated and all bolts for joints shall be of high tensile steel. The resistance of any length of conductor containing joints shall be no greater than that of an equal length without a joint.

Primary busbars and connections shall be marked clearly and shall be placed for standard phase sequence Red (R), Yellow (Y) and Blue (B) counting from front to rear, top to bottom or left to right as viewed from the switching device operating mechanism side.

3.8 CIRCUIT BREAKER

Circuit breakers shall be 24 kV, 3 phase SF6 types with making capacity, short time current rating, operating duty of the circuit breaker and the performance of all trip coils in compliance with BS 5311: 1988 - Specification for high-voltage alternating current circuit-breakers for a breaking capacity of 25 kA rms.

The moving portion of each circuit-breaker unit shall consist of a three-pole circuit-breaker with

khng gian cn thit cho in p, c cch in hon ton hay c epoxy bo v thch hp. Khng c s dng bng cch in.

Thanh ci chnh, s u ni v nhng thanh gi ca chng phi l loi c cho php s dng v c kh nng chu c dng ngn mch nh mc trong thi gian ngn mch l 3 giy.

Khi thanh gi thanh ci s dng cch in loi c hay loi nha, chng phi c lp bn chng rt m trn b mt.

Cc im ni t thanh ci trong cc b ring l s c dng nh mc lin tc khng nh hn cc thit b bao gm.

Ti nhng im chuyn tip hay im ni, thanh ci v nhng u ni s bng thic hay m bc v tt c bulong phi l thp chu lc. in tr ca dy dn c u ni khng c ln hn ci c chiu di tng ng khng c u ni.

Thanh ci chnh v u ni phi c nh du r rng v c t theo th t pha (R), Vng (Y), Xanh (B), tnh t trc ra sau, t trn xung , hay t tri qua phi khi nhn t pha thit b ng ct c kh.

3.8 CU DAO T NG (CB)

CB l loi 24kV, 3 pha vi kh nng ng (nh) loi SF6, gi tr dng in thi gian ngn, chc ning hot ng v hiu sut lm vic phi ph hp vi BS 5311: 1988 - Specification for high-voltage alternating current circuit-breakers cho dung lng ct l 25 kA rms.

Phn ng ca CB gm mt CB 3 cc c c cu hot ng bng c kh, thit b ng ct chnh v



operating mechanism, primary and secondary disconnecting devices, auxiliary switches, position indicators and the necessary control wiring all mounted on a substantial steel framework. The framework and all metal parts of the moving portion apart from current carrying parts, shall be solidly earthed via the fixed portion. The earthing of the moving portion shall be to the approval of the Engineer. Mean of registration shall be provided so that circuit breakers may be readily placed and secured in the correct position in the fixed portion.

SF6 circuit breakers shall consist of a cylindrical mild steel gas enclosure with six individual sealed epoxy resin bushings. The drive shaft to the moving contacts shall pass through a rotating gas seal. The normal pressure of the SF6 gas shall not exceed 4 bar. The leakage rate of SF6 gas shall be less than 1% per annum. The SF6 circuit breaker shall be capable of interrupting its rated normal current at atmospheric pressure. Fixed and moving contacts, complete with arcing contacts, shall be provided for each phase.

3.9 OPERATING MECHANISM

The circuit breaker shall be provided with motor charged spring, electrical closing, mechanical hand close, electrical shunt trip and mechanical hand trip facilities. A 4-digit operation counter shall be provided to register the number of operations.

The mechanism shall be trip-free type so that the circuit-breaker shall be free to open during the closing operation immediately its tripping device operates. The circuit breaker shall be capable of closing fully and latching against its rated making current. Facilities shall be provided for manual slow closing and slow opening of the circuit breaker for maintenance purposes. The circuit breaker shall be so designed that these facilities cannot be used when the circuit breaker is in the service or earthing position.

The protective circuit shall be suitable for

ph, cng tc ph, hin th v tr v dy iu khin, tt c c gn trn mt khung thp chc chn. Khung thp v tt c phn kim loi ca phn ng t nhng phn mang in s tch ri vi phn c in thng qua cc phn c nh. Ni t ca cc phn ng s c chp thun bi Qun l K thut. C ngha rng s chp thun s c cung cp cc CB c th thay th v c m bo trong v tr ng trong v tr c nh.

SF6 CB gm c mt ng kh thp nh hnh tr gn 6 ng nha tng hp ring l. Trc ko ng ct cc tip im s i qua mt m kh xoay. Ap sut bnh thng ca kh SF6 khng vot qu 4 bar. S r r ca kh SF6 s khng vt qu 1% trn 1 vng. CB SF6 c kh nng ct dng din nh mc ca n ti mt p sut kh. Mi pha s c nhng tip im ng, c nh, nhng tip im khng c h quang in.

3.9 C CU C KH

CB c m t sc dng l xo, cun dy ng, phn c kh ng bng tay, thit b ct bng in v bng tay, cc cun ct bng tay v bng in. Mt b m s ln hot ng vi 4 ch s.

Phn c kh l loi t ct CB ct ngay lp tc nu ng CB khi cun ct ang hot ng. CB phi c kh nng ng hon ton v gi li ti gi tr dng nh mc ca n. CB cn c kh nng ng, m chm bng tay thun li cho vic bo tr. CB cng s c mt s tin dng khc c thit k nhng khng s dng n khi CB a vo s dng hay b tr ni t.

Mch bo v s hot ng c t in p 30V DC



operation from a 30V D.C. battery supply.

The following coils shall operate continuously with their coils at an ambient temperature of 40oC, over a voltage range as follows:-

Spring charge motor: 85 - 110% of nominal supply voltage

Closing solenoid: 85 - 110% of nominal supply voltage

Shunt trip release coil: 70 - 100% of nominal supply voltage

Auxiliary switches shall be provided to interrupt the closing supply or the tripping supply when the operation of closing and tripping respectively has been completed.

All operating coils for use on the D.C. supply shall be connected so that failure of insulation to earth does not cause the coil to become energised.

Tripping and closing circuits shall be provided with fuse in each pole on each unit and shall be independent of each other and all other circuits.

Approved, positively driven mechanically operated indicating devices shall be provided to indicate whether a circuit breaker is in the open or closed service, isolated, test or earthed positions.

3.10 ISOLATING DEVICES AND SHUTTERS

When isolation is effected by withdrawal of the circuit breaker, provision shall be made for positively locating the circuit breaker in the service, isolated and earthing positions. Stops shall be provided to prevent over-travel and each position shall be clearly indicated. A mechanical selector mechanism shall be utilised such that when a particular position is selected it is impossible to locate the circuit-breaker in any other position.

Isolating devices shall incorporate self-aligning

cung cp t bnh ac quy.

Nhng cun dy sau s hot ng c lin tc ti nhit 40oC, cp in p hot ng nh sau:

M t sc : 85 - 110% in p nh mc

Cun dy ng : 85 - 110% in p nh mc

Cun dy ct : 70 - 100% in p nh mc

Nhng tip im ph c s dng tng v tr ring ca CB khi c ng hay m.

Tt c cun dy hot ng phi s dng ngun DC trnh cun dy hot ng khi cch in i vi t b h.

Mch ng ct phi c cu ch bo v cho mi cc v ring r vi nhau v vi nhng mch khc.

Thit b hin th v tr lm vic ca CB c trang b xc thc n ang m hay ng, kim tra, cch ly khi mch hay c ni t.

3.10 THIT B CCH IN V NHNG L CHN

Khi CB c ko cch ly ra khi mch, s c nhng hin th ch r tng trang thi v tr hot ng ca CB, v tr cch ly v ni t. S c v tr dng trnh CB khng b ko ra qu mc v mi v tr s c hin th r rng. Mt nm xoay bng c kh s c s dng khi tng v tr ca CB c chn, CB khng th t vo nhng v tr no khc c.

Thit b cch ly s lin kt vi nhng tip im t



contacts, the fixed contact of which shall be such that access can readily be obtained for maintenance purposes.

Metal shutters shall be provided to completely shroud fixed isolating contacts of the circuit-breaker busbar and feeder circuit. These shutters shall be opened and closed automatically by the movement of the circuit breaker carriage and shall prevent access to the fixed isolating contacts when the circuit breaker is withdrawn. The shutters for the fixed isolating contacts connected to busbar and cables shall have independent operating mechanisms. Shutters for the busbars shall be painted red and with white lettering BUSBAR. Those for the circuits shall be painted yellow with white lettering CIRCUIT.

To facilitate testing, a device shall be provided for fixing, but not locking, shutters in an open position. The device shall be arranged so as to be cancelled by the moving portion, to ensure that the automatic feature of the shutter is restored.

Self-aligning plug and socket isolating devices of an approved design shall be provided for all auxiliary circuits.

3.11 PADLOCKING FACILITIES

The Sub-Contractor shall supply sufficient padlocking facilities for the following functions:-

a) To lock closed, the circuit breaker compartment door.

b) To lock closed, each safety shutter in circuit breaker compartment.

c) To lock closed, the V.T. safety shutters.

d) To disable the manual "TRIP" device when the circuit breaker is in the "EARTH" position and "CLOSED".

sp xp, tip im c nh, d dng kim tra trong cng tc bo tr.

L chn kim loi c trang b che chn nhng tip im cch ly c nh vi thanh ci ca CB v ca mch. Nhng l chn ny s ng, m t ng khi di chuyn CB v ngn khng tip xc vi nhng tip im cch ly c nh khi CB c ko ra. Nhng l chn cho nhng tip im cch ly c nh c ni n thanh ci v s c c cu hot ng c lp. Nhng l chn bo v thanh ci s c sn v ch trng BUSBAR. Nhng phn khc trong mch s c sn vng vi ch trng CIRCUIT.

d dng cho cng tc kim tra, s c mt thit b gi c nh, nhng khng phi l kho, nhng l chn v tr m. Thit b s c sp xp bi b phn chuyn ng, m bo rng tnh nng t ng ca nhng l chn c khi phc.

Trong thit k s c nhng plug v cm cch ly t sp xp c lp t cho tt c cc mch ph.

3.11 NHNG B KHO

Thu ph s cung cp nhng b kho phc v cho nhng chc nng sau:

a) ng kha, ca t cha CB.

b) ng kho mi l chn an ton trong ngn cha CB.

c) ng kho, nhng l chn an ton V.T

d) cch ly thit b hot ng "TRIP" bng tay khi CB ang v tr "EARTH" v "CLOSED".



e) To lock the selector mechanism on circuit-breaker isolated and service positions.

3.12 INTERLOCKING FACILITIES

Mechanical & electrical interlocking facilities shall be provided to prevent the following operations:-

a) Withdrawal/ insertion of circuit breaker into the isolating contacts unless the circuit breaker is in its open position

b) The closing of a circuit breaker unless it is in its service, isolated, earthed or completely withdrawn position

c) Closing of a circuit breaker in service position unless the auxiliary contacts are made

d) Insertion of a circuit breaker into service position when its pole parts are not in their proper positions

e) Closing of earthing switch when the circuit breaker is in closed position or vice versa

f) Closing of a circuit breaker unless its spring is full charged

3.13 EARTHING AND EARTHING DEVICES

All metal parts other than those forming part of an electrical circuit shall be connected in an approved manner to a hard-drawn, high conductivity copper earth busbar which shall run the full length and be bolted to the main frame of the switchboard without joint. The earth busbar shall be rated to carry currents equal in magnitude and duration to that associated with the short circuit rating of the equipment. Minimum size shall be 50mm x 6.4mm.

The design and construction of the equipment shall be such that all metal parts, other than current carrying parts, or withdrawal equipment

e) kho nm vn c kh trn CB cch ly v v tr lm vic.

3.12 KHO LIN NG

Kho lin ng c v in s c trang b ngn nhng hot ng sau:

a) S ko hay ci CB vo trong nhng tip im cch ly tr khi CB vo trong ng v tr m ca n.

b) ng CB tr khi n ang v tr hot ng, cch ly, ni t hay hon ton c ko ra.

c) ng CB vo v tr hot ng tr khi nhng tip im ph c sn sng.

d) a CB vo trong v tr hot ng khi nhng cc ca n cha vo ng v tr.

e) ng tip im ni t khi CB v tr ng hay ngc li.

f) ng CB tr khi l xo sc .

3.13 NI T V NHNG THIT B NI T

Tt c nhng phn kim loi khng thuc v mch in s c ni theo mt kiu cho php ko ra, thanh ng c tnh dn in cao s chy di khng ni gia v c bt bu long vo khung chnh ca t in. Thanh ni t phi c kh nng mang ti vi dng in nh mc v trong sut thi gian c dng ngn mch xy ra trn thit b. Kch thc nh nht l 50mm x 6.4mm.

Thit k v lp ni t s gm tt c nhng phn kim loi, tr nhng phn mang in, hay nhng thit b di ng th s c ni t trc khi ng



are earthed before the primary connections are made.

Metal cases, supports and bases of all instruments, relays or other associated components mounted on the switchgear shall be connected to the earth busbar by conductors of not less than 2.5 mm2 cross sectional area.

When components are provided for mounting separately, each shall be provided with an earthing terminal not less than 35 mm2 cross sectional area.

Integral busbar earthing by means of the circuit breaker shall be provided on circuit breakers. Busbar earthing shall only be possible when all the circuit breakers which can feed the busbars are locked open. With the circuit earthed, shutters over unearthed fixed main isolating contacts shall be closed. Earthing facilities employing earth switches are not acceptable.

Earthing switch with fault making capacity for cable termination shall be provided. Earthing switch shall be designed for high speed operation independent of operator.

Earthing devices shall have a short circuit rating equal to that of their associated circuit-breaker.

Padlocking facilities shall be provided for the purpose of preventing inadvertent earthing.

Labels shall be provided to show whether the equipment is prepared for "SERVICE", "BUSBAR EARTH" or "CIRCUIT EARTH". Such indication shall be visible from the front of the equipment at all times.

3.14 TESTING FACILITIES

All circuit breaker units shall be provided with facilities to enable high tension tests to be carried out.

Provision shall also be made for temporarily

mnh.

Thng kim loi, gi , v ca nhng dng c, r le hay nhng thit b lin quan khc gn trn my ct s c ni vi thanh ci t bng dy dn khng nh hn dy c tit din 2.5mm.

Khi nhng b phn cung cp c lp ring r, mi ci s c lp bng mt u ni t khng nh hn 35mm.

Ni t thanh ci bng CB s c trang b trn CB. Chng ch c th c ni t khi tt c CB, ci m c th a thanh ci vo c m kho. Vi mch c ni t, nhng l chn bn trn nhng tip im cch ly c nh chnh khng ni t s b ng. Dng nhng cng tc ni t th khng c php.

Cng tc ni t c bo v cho u ni cp khi ng mch s c cung cp. Cng tc ni t s c thit k cho hat ng tc cao khng ph thuc vo ngi vn hnh.

Thit b ni t s c mt gi tr dng ngn mch tng ng vi CB ca n.

Kho s c trang b ngn nga s ni t ngoi mun.

Nhng nhn thng bo s c cung cp ch thit b sn sng cho "SERVICE", "BUSBAR EARTH" or "CIRCUIT EARTH". Nhng nhn thng bo s lun c nhn thy t mt trc ca thit b.

3.14 THIT B KIM TRA

Tt c CB s c nhng thit b cho php kim tra in cao p.

Nhng mch ph cng s c lp t tm thi khi



completing the auxiliary circuits when the circuit breaker is isolated and withdrawn, to enable the functioning of the circuit breaker to be tested.

When current transformers and protective relays are fitted, facilities shall be provided for primary and secondary injection tests to be carried out. These facilities shall be such that wires and connections need not be disconnected for the tests to be carried out.

3.15 MECHANICAL INDICATION

Indication shall be provided to clearly indicate whether a circuit breaker is in the open or closed, service, isolated, test or earthed position.

Positively driven mechanical indicating devices shall also be provided on all equipment to indicate the following where applicable:-

Circuit breaker "OPEN" or "CLOSED"

Circuit breaker "SPRING CHARGED" or "SPRING FREE"

3.16 AUXILIARY SWITCHES

Approved, positively driven in both directions, auxiliary switches shall be provided on all circuit-breakers and isolators for indication, control and interlocking.

Auxiliary switches shall be strong, have a positive wiping action when closing and shall be mounted in an accessible position clear of operating mechanisms.

Auxiliary switches shall be designed to make, break and shall carry, without undue heating, the current of their associated circuit. Auxiliary switches shall be rated for 10A operational current and shall be capable of breaking at least 2A at 220V D.C. with a circuit time constant not less than 20 ms.

Not less than eight spare auxiliary switches shall

CB c cch ly v ko ra, cho php kim tra nhng chc nng lm vic ca CB.

Khi bin dng v r le bo v c lp, thc hin c, nhng cng c ny s c kim tra s phu s cp v th cp. kim tra, nhng thit b h tr nh dy dn, u ni cn thit khng cn tho ra.

3.15 HIN TH C KH

S hin th phi r rng bit trng thi CB ang m, ng, hot ng, cch ly, kim tra hay ni t.

Thit b hin th phn chuyn ng c kh s c trang b trn tt c thit b ch nhng trng thi sau:

CB "OPEN" or "CLOSED"

CB "SPRING CHARGED" or "SPRING FREE"

3.16 CNG TC PH

Nhng cng tc ph, c php s dng, c kh nng thay i trng thi mt cch r rng c hai hng, s trang b trn tt c CB v hp cch in hin th, kim sot v kho ln nhau.

Nhng cng tc ph phi chc chn, dt khot khi ng v s c lp trn v tr thun tin cho s hot ng v mt c kh.

Nhng cng tc phu c thit k s dng cho ng ct dng din trong mch nhng khng gy qu nhit. Nhng cng tc ph c dng in cho php l 10A v th ct ti gi tr t nht l 2A-220V DC vi thi gian ln hn 20 ms.

Mi CB s c nhiu hn 8 cng tc ph d tr v 4



be provided with each circuit-breaker and not less than four with each isolator. Each spare contact shall be readily changeable from normally open to normally closed and vice versa. All auxiliary switches shall be wired up (via secondary disconnecting devices if no withdrawable equipment) to a terminal board on the front of the fixed portion arranged in the same sequence for each individual unit of the same type.

3.17 ANTI-CONDENSATION HEATERS

Anti-condensation heaters of an approved type shall be provided inside each cubicle. They shall be thermostatically controlled, shrouded and located so as not to cause injury to personnel or damage to equipment. The heaters shall be switched by a double-pole miniature circuit-breaker, with a "cubicle heaters on" indication lamp which shall be installed on the front panel of the switchgear. The heaters shall operate from a 240V 50 Hz single phase A.C. supply.

3.18 INSULATORS

Minimum insulator lengths for enclosed indoor-type circuit breakers shall be as follows:-

Rated voltage: 24 kV

Minimum length of insulator in air : 127mm

3.19 CURRENT TRANSFORMER

Current transformers shall comply with BS 7626: 1993 - Specification for current transformers and shall be suitable for the operation of protective gear, instruments and/ or metering equipment. The design characteristics shall be to the Engineer's approval. The current transformers for each panel shall be of the rating as indicated on the Sub-Contract Drawings.

The short time current rating of the primary

ci cho mi mt b cch ly. Mi cng tc d phng phi d dng i trng thi t thng m sang thng ng v ngc li. Tt c cng tc ph s c ni (thng qua thit b ngt th cp nu khng c thit b ko ra c) n trm ni dy trn mt trc ca phn c nh c sp xp theo cng th t cho ring tng ci cng loi.

3.17 IN TR SI

in tr si chng ngng t cng chng loi s c lp trong mi ngn t. Chng c kim sot bng thermostat. Chng c che y v t sao cho trnh gy nguy him cho ngi v h hng thit b. Chng c cp ngun bi MCB 2 cc, vi mt n hin th "cubicle heaters on" c lp ng trc t in. Ngun cp l 240V 50 Hz mt pha AC.

3.18 CCH IN

Chiu di cch in ti thiu cho loi CB trong nh nh sau:

in p nh mc: 24 kV

Khong cch cch in ti thiu : 127mm

3.19 BIN DNG

Bin dng s theo tiu chun BS 7626: 1993 - Specification for current transformers v phi ph hp bo v thit b, dng c, hay thit b o lng. Tiu chun thit k phi c Qun l K thut ng . Cc bin dng cho mi t phi c gi tr nh c ch trn bn v.

Gi tr dng in khng thng trc ca cun s



windings of the current transformers shall be not less than that of the associated circuit breaker. The secondary windings of each set of current transformers shall be capable of being open circuited for one minute with the primary winding carrying the rated current.

Current transformers shall be air-insulated and shall be mounted in the fixed portion of the switchgear with a method of securing in position such that undue mechanical pressure cannot be exerted on the transformer windings.

CT characteristics, including magnetization curves of each type of current transformer shall be submitted for approval.

All current transformers shall be installed with the P1 terminals adjacent to the busbars. The polarity of the primary and secondary windings of each current transformer shall be clearly indicated and labels shall be fitted in a readily accessible position to indicate the ratio, class and duty of each transformer.

Current transformers for indication or metering shall have their secondary windings earthed at the switchgear. The secondary windings of current transformers for protection shall be earthed at the panel which accommodates the associated relay. The relay connection shall be made via a removable link.

3.20 VOLTAGE TRANSFORMER

Voltage transformers shall be provided for the operation of the protective gear, voltage regulating equipment and instruments. Voltage transformers shall comply with BS 7625: 1993 - Specification for voltage transformers and shall be of the following rating:-

a) System Voltage: 22 kV 3 phase 50 Hz

b) Highest Equipment Voltage: 24 kV

c) Transformation Ratio: 22 kV/110 V

cp phi ln hn CB bo v n. Cun th cp s phi ct mch trong vng 1 pht khi cun s cp mang dng in nh mc.

Bin dng s cch in chn khng v c lp trn phn c nh ca b chuyn mch mt cch m bo sao cho lc c kh tc ng ln bin dng khng c qu mc.

c im ca CT, nh ng cong t ho ca mi loi bin dng phi c xem xt v ng .

Tt c bin dng phi c lp t bng u ni P1 gn vi nhng thanh ci. Cc ca cun s v th cp ca mi ci phi c hin th mt cch r rng v nhn phi t v tr sao cho d dng c oc t s, loi, cng sut ca mi ci.

Bin dng hin th hay o lng s c cun s cp ni t ti switchgear. Cun s cp ca bin dng bo v s c ni t vo ni cung cp cho nhng r le. u ni r le s c ni bng u ni c th m c.

3.20 BIN P

Bin p c cung cp cho hot ng ca thit b bo v, nhng dng c v trang thit b n p, bin p phi ph hp vi tiu chun BS 7625: 1993 - Specification for voltage transformers v s c nhng gi tr sau:

a) in p h thng : 22 kV 3 phase 50 Hz

b) in p ln nht : 24 kV

c) T s bin p : 22 kV/110 V



d) Rated Output per Phase: 200 VA

e) Accuracy: Class 0.5 for measurement

f) Voltage Factor: 1.2 continuously & 1.5 for 30 sec

g) Insulation Level: 60 kV R.M.S.

V.T.'s shall have two separate windings for primary and secondary and shall be dry type with epoxy encapsulation. They shall be housed in naturally air-cooled totally enclosed sheet steel enclosures and shall be of isolating and retractable type.

The primary winding shall be connected through renewable fuses to BS 2692 - Fuses for voltages exceeding 1000 V A.C. with current limiting features. Secondary windings shall be connected through circuit breakers labeled to indicate their function and phase colour, to the appropriate circuits.

Primary fuses shall only be removed when the V.T. is entirely withdrawn out at the isolated position.

Voltage transformers shall be capable of being connected and disconnected from the equipment whilst in service. Facilities for padlocking in the service position shall be provided. A set of safety shutters, capable of being padlocked, shall be provided to automatically cover the fixed contacts when the V.T. is isolated. Particulars of shutters shall be identical to those for circuit breakers. The shutters shall operate automatically by positive drive activated by movement of the V.T. assembly.

Class of insulation for components and windings shall be Class F.

V.T. secondary windings shall be earthed at the switchgear through a link which can be removed for insulation testing. The earthing of voltage transformers shall be approved by the Engineer.

d) in p ng ra mi pha : 200 VA

e) chnh xc : Class 0.5 cho o m

f) H s in p : 1.2 lin tc & 1.5 for 30 giy

g) Loi cch in : 60 kV R.M.S.

V.T. s c hai cun s v th cp cch ly v l loi kh c bc epoxy. Chng s ct trong khng kh t nhin, hu nh c lm bng thp l, cch in, v l loi co gin c.

Cun s cp s c ni qua cu ch c th thay c theo BS 2692 - Fuses for voltages exceeding 1000 V A.C. c t tnh gii hn dng. Cun th cp s c ni qua CB c dn nhn ch chc nng ca chng v mu pha trong mch ca chng.

Cu ch ca s cp ch c tho ra khi V.T hon ton c ko ra khi v tr c cch ly

V.T phi c kh nng ni v tho c ra khi thit b trong khi ang ch vn hnh. B kho v tr ang vn hnh s c trang b. Mt b l nhng l chn bo v c chc nng kho c, cng s c trang b t ng che nhng tip im c nh khi V.T c cch ly. Nhng l chn s c t im ging nhau so vi nhng CB ca chng. Nhng l chn s hot ng t ng bi b truyn ng c kch hot bng ng tc tho V.T.

Loi cch in cho V.T v dy l loi F.

Cun th cp ca V.T. s c ni t ti b chuyn mch bng mt u ni c th tho ri kim tra cch in. S ni t ca V.T s phi c Qun l K thut ng .



Secondary circuits of voltage transformer shall not be paralleled.

Connections to primary isolating contacts shall have a thermal current rating of 200A and a short circuit capacity of the following:-

Rated highest equipment voltage: 24 kV

Rated short circuit breaking current: 25 kA R.M.S.

Type test on temperature rise shall be certified by the manufacturer on tests undertaken in the manufacturer's works.

3.21 CABLE BOX

Cable boxes shall be suitable for terminating the cables directly into the switchgear. The dimensions and terminal arrangements shall be submitted for approval by the Engineer before manufacture is commenced.

All cable boxes shall be suitable for use with air insulated heat shrinkable elastometric PCP cable termination and shall be designed to exclude the entry of air, dust, or moisture. The internal surfaces of cable boxes shall be cleaned of all scale and rust after cleaning and priming and shall be finished with polyester powder paint.

The cable box shall be suitable for 3 core XLPE/SWA/PVC cables. Where cable boxes are provided for three-core cables, the sweating sockets on the two outer phases shall be inclined towards the central to minimise bending of the cable cores. Where there is more than one core per phase, the socket block shall be so designed as to minimise bending of the cable cores.

All cable terminals shall be of adequate size to ensure no over-heating takes place at rated current. Neon indicators fed from potential divider on each phase of the cable termination shall be provided in front of the panel to indicate either cable are "live" or "dead".

Mch nh th ca V.T khng c ni song song.

S u ni n nhng cng tc cch ly chnh s c mt gi tr dng in sinh nhit l 200A v dung lng ngn mch nh sau:

in p nh mc ln nht ca thit b : 24 kV

Dng in ct ngn mch nh mc : 25 kA R.M.S.

Loi kim tra s gia tng nhit s c chng nhn bi nh sn xut trong cng tc kim tra ca nh sn xut.

3.21 HP NI CP

Hp ni cp phi thch hp ni cp trc tip ln trn t my ct. Kch thc v s sp t trm ni phi c Qun l K thut xem xt v chp thun trc khi ch to.

Tt c hp ni cp phi ph hp p ng c khong cch khng gian, s gin n nhit, trm ni dy bng cht nha n hi PCP v c thit k chng li khng kh, bi, hi m. B mt bn trong ca hp ni dy phi sch, khng b r, bi sau khi v sinh, sn lt v sn polyester.

Hp ni phi thch hp vi cp 3 rut XLPE/SWA/PVC. Nhng ch m hp ni cp s dng cp 3 rut, cm hn thic trn 2 pha ngoi s c khuynh hng nghing vo trung tm gim thiu cong ca cp. Nhng ch c hn 1 dy mi pha, b cm s c thit k sao cho gim thiu cong ca cp.

Tt c u ni cp phi c kch c tng thch m bo khng b qu nhit khi mang ti vi dng nh mc. n hin th neon c cung cp t b chia p trn mi pha ca u ni cp s c lp pha trc ca t hin th cp ang c ngun hay mt.



The insulators and fittings shall be unaffected by atmospheric and climatic conditions, ozone, acids, alkalis, dust deposits or rapid temperature changes likely to arise when operating in the site conditions and shall be designed so as to facilitate cleaning.

3.22 PROTECTION RELAYS

The following shall be provided in a separate compartment where specified:-

a) Three single element induction disc type I.D.M.T.L. over-correct protection relays, c/w high set instantaneous elements, with current setting of 50% to 200% in 7 equal steps and time setting of 0-3s continuously adjustable at 10 times the current setting. The time-current characteristics shall be the 3/10 category in accordance with BS 142 - Electrical protection relays.

b) One single element induction disc type I.D.M.T.L. earth fault relay with current setting of 10% to 40% in 7 equal steps and time setting of 0-1.3s continuously adjustable at 10 times the current setting.

c) Incoming panel: Pilot wire Solkor RF/HOR 4 or equal.

d) Feeder panel: Temperature trip from transformers; differential current and inter-tripping to L.V. circuit breaker.

e) One single unit trip circuit supervision relay which shall supervise the trip circuit of the circuit breaker and initiate audible alarm and visual indication if the trip circuit fails. It shall be connected across the trip supply, be normally energised and delayed drop off if trip voltage falls below 40% of nominal value. It shall be suitable for use at nominal trip voltage of 30V D.C. and be hand reset.

All relays provided shall comply with BS 142 and shall be of draw out case type and flush mounted

Vt cch in v khp ni phi khng b nh hng bi iu kin khng kh, thi tit, kh ozone, axit, kim, ng bi hay s thay i nhit t ngt xy ra khi vn hnh trong iu kin v phi c thit k sao cho d dng v sinh.

3.22 R LE BO V

Nhng thit b bo v sau s c lp t trong mt hp ring r nh:

a) Ba a cm ng n loi I.D.M.T.L. nhng r le bo v iu chnh chnh xc vi cc yu t tc thi, vi dng chnh c t 50-200% trong 7 mc bng nhau v thi gian set t 0-3s v c th iu chnh c n 10 ln dng in set. c tnh thi gian- dng in s l 3/10 ph hp vi BS 142 - Electrical protection relays.

b) Mt a cm ng n loi I.D.M.T.L. r le bo v chm t vi dng set t 10-40% trong 7 mc bng nhau v thi gian set t 0-1.3s c th iu chnh n 10 ln gi tr dng in set.

c) T ngun n: dy hin th loi Solkor RF/HOR 4 hay tng ng.

d) T ngun cp: bo v qu nhit t bin th, lch dng, v inter-tripping n CB in p thp (L.V. circuit breaker).

e) Mt rle ct bo v, loi s gim st s ct mch ca CB v pht ra tn hiu chung bo v n hin th nu mch ct hng. N s kt ni tt c cc s cung cp s c, thng hot ng v lm tr trn in p ct di 40% gi tr thng. N s c in p hot ng l 30V D.C v c nt nhn reset.

Tt c rle lp t phi tun theo quy nh BS 142 v l loi hp ko ra v c lp ngay vo mt



on the front panel of the switchgear. All terminals to relays shall be suitably insulated and the circuits shall be suitably fused, using H.R.C. fuses.

The relay contacts shall be of the double break type. The relay contacts shall have adequate making and breaking capacity. Unless otherwise specified, contacts shall be capable to make and carry 7500 VA for 0.5 second with a maximum of 30A and 660V.A.C. or D.C.

A red coloured latch shall be provided at the side of each relay which shall isolate the trip circuit supply when the latch is moved from its fully locked position and before the relay is drawn out.

The Sub-Contractor shall supply and install the alarm to be initiated by the auxiliary relay for transformer temperature protection and the trip circuit supervision relay.

The pilot wire protective system shall operate in conjunction with similar equipment at the remote Power Grid end of the feeder via pilot cable. The pilot cables used by Power Grid will be either 5, 10 or 20 pair, 1.5mm2 copper conductor polyethylene insulated, copper tape screened, polyethylene oversheathed armoured type.

3.23 PILOT AND CONTROL CABLES

All feeder panels shall be provided with termination for a twin core 1.5mm2 cable for termination of pilot wires from Power Grid switchgear.

Each transformer panel shall come with sufficient number of control cable glands for alarm/ control/ tripping purposes.

The size of the cable gland for transformer and feeder panel should be suitable for the overall diameter sizes of pilot/ control cable used. The minimum size of alarm/ tripping control cable for the transformer panel is 2.5mm2 in cross-sectional area.

trc ca t. Tt c u ni n rle phi c cch in ph hp v mch c lp cu ch thch hp, s dng loi H.R.C.

Nhng tip im ca rle phi l loi i. Chng c dung lng ng v ct tng thch. Tr phi c nhng yu cu v k thut khc, nhng tip im phi chu c cng sut 7500VA trong 0.5 giy vi dng in ln nht 30A- 660V A.C hay D.C

Mt ci cht nh du mu c lp bn cnh ca mi rle ci m s c lp ngun ct mch khi cht c rt ra khi v tr kho ca n v trc khi rle c ko ra.

Nh thu s cung cp v lp t thit b bo ng thng qua role ph bo v qu nhit cho bin th v role gim st mch ct.

H thng bo v dy iu khin s vn hnh cng vi thit b tng t ti li ngun, im cui ca ng dy thng qua cp iu khin. Nhng cp iu khin c s dng bi li ngun s l 5, 10, hay 20 cp, loi dy ng bc polyethylene 1.5mm, ng c bc dy bng, bc st ph polyethylene.

3.23 CP DN V IU KHIN

Tt c t ngun cung cp s c lp trm ni dy cho loi cp i 1.5mm ni dy dn t t ng ct li ngun.

Mi t bin th phi lp s dy vi mc ch bo ng, iu khin, ct mch.

Kch thc ca ming m cp cho bin th v t ngun cung cp phi ph hp bao trm ton b cp dn/ iu khin c s dng. ng knh nh nht ca cp iu khin bo ng/ ct mch cho bin th l 2.5mm.



Each panel shall be provided with a terminal block. Adequate terminals with spares and cable glands suitable for Power Grid control cable shall be provided.

3.24 INDICATING INSTRUMENTS

All indicating instruments shall be to BS 89 - Direct acting indicating analogue electrical measuring instruments and their accessories 1st Grade moving iron spring controlled with 100mm, 240o scale dials and external zero adjustment. Integrating meter shall be to BS 5685 - Electricity meters.

Each panel shall be equipped with neon potential indicators to indicate whether each phase on the circuit side of the panel is "alive". The indicators shall be energised from condenser bushings on the panel.

Each indicator shall be wired with a normally-closed push-button switch in parallel. The operation of this switch shall light up the indicators.

The indicators shall be mounted at the front of the switch panel and shall be shielded from extraneous light. The neon lamps shall be of adequate dimensions to provide clear indication under all conditions. The terminals at neon indicators shall be adequately shielded with positive means to prevent operating personnel inadvertently coming into contact with the 'live' terminals.

Laminated plastic sheet engraved labels of ample size shall be provided for each of the units on the switchboard. A means of fixing these labels shall be provided, other than by adhesives. The use of embossing tape for labeling is not acceptable.

The Sub-Contractor shall, during the progress of manufacture of the switchboard, submit a schedule of labels for approval by the Engineer before engraving is carried out.

Mi t s c lp nhng trm ni dy. Nhng im ni dy tng thch v nhng ming m dy ph hp cho cp iu khin ca li in s c trang b.

3.24 THIT B HIN TH

Tt c nhng thit b hin th phi theo BS 89 - Direct acting indicating analogue electrical measuring instruments and their accessories mc di chuyn th nht ca l xo c iu khin bng 100mm, 240o v chnh v khng bn ngoi. B ng h s l loi BS 5685 - Electricity meters.

Mi t in s c trang b dn bo hin th tng pha trong t ang ang c in hay mt. Nhng n bo s c cp ngun t b ng t li trn t.

Mi n hin th s c ni song song vi mt cng tc nhn thng ng. n s sng mi khi nt nhn ny hot ng.

n hin th s c lp mt trc ca t v s c che khi b chi nh sng t bn ngoi. Nhng n neon phi ph hp cho s chiu sng r rng trong mi iu kin. Nhng u ni ca n neon phi c che chn thch hp trnh tip xc gin tip ca ngi ln phn c in.

Nhng tm nha plastic c khc nhn vi nhiu kch c khc nhau s c gn ln trn tng phn ca t in cao p. Mt cch gn nhng ci nhn ny s c thc hin, khc vi cch dng cht kt dnh. Khng c php s dng dy bng khc ni lm nhn.

Trong sut qu trnh lp rp t in my ct, nh thu s phi a ra danh sch ca nhn Qun l K thut xem xt trc khi chng c ng du.



Warning labels shall be affixed to the rear panels and shall be coloured red with white lettering denoting "DANGER - LIVE BUSBAR INSIDE".

In addition to automatic screening shutters and barriers, warning labels shall also be provided for all live parts such as test terminal blocks.

A brief operation instruction of the switchboard together with a detailed schematic wiring diagram listing out all the relevant switching steps and interlocks for commissioning/ decommissioning of part or whole of the 22 kV switchboard shall be provided by the Sub-Contractor in a frame adjacent to the switchboard.

All equipment shall be solidly earthed. The earthing system shall comply with Singapore Standard Code of Practice CP 5: 1988 - Wiring of electrical equipment of buildings, Singapore Standard Codes of Practice CP: 16 - Earthing and CP 17: 1991 - The maintenance of electrical switchgear for voltages up to and including 22 kV.

An earth bar shall be provided in the 22 kV switchroom.

3.26 D.C. SUPPLY

A 30V d.c. supply system shall be provided for the opening and closing of the circuit breakers operating auxiliary and protective equipment/ control devices, etc. as specified. The system shall comprise a battery section and a charger section each housed within separate compartments of a cubicle, c/w control wiring, protective devices and other accessories as required, supplied by a single proprietary manufacturer. The cubicle shall be externally finished in semi-gloss stoved enamel or cellulose to match the switchboard.

The system shall also incorporate a double wound step-down transformer of appropriate rating as well as the following components:-

Nhn cnh bo s dn ng sau t in v s c nn , ch trng: "DANGER - LIVE BUSBAR INSIDE".

Thm vo , t ng che nhng l chn v hng ro, nhng bin cnh bo cng s c gn ln nhng phn c in nh nhng trm u dy.

Mt bng thng tin v hot ng ca t in cng vi mt bn v dy dn, bng lit k cc bc lin quan n vic ng ct, kho lin ng ca t cho hoc khng cho mt phn hay ton b t cao p 22kV vo hot ng cng s c gn trong khung v c cung cp bi nh thu.

Tt c cc thit b s c ni t mt cch chc chn. H thng ni t phi tun theo tiu chun Singapore CP 5: 1988 - Wiring of electrical equipment of buildings, Singapore Standard Codes of Practice CP: 16 - Earthing and CP 17: 1991 - The maintenance of electrical switchgear for voltages up to and including 22 kV.

Mt thanh ni t s c lp trong phng my ct 22kV

3.26 NGUN D.C

Mt ngun cung cp 30 V d.c s c cung cp ng, m ph cho CB v bo v trang thit b hay thit b bo v v.v nh thit k. H thng s gm bnh c quy v b phn sc, mi b s c cha trong mt ngn ring ca t in, vi dy iu khin, thit b bo v v nhng thit b h tr khc nh yu cu, c cung cp bi mt nh sn xut c ng k. Mt ngoi s c ph lp men gm hay cellulose hp vi t cao p.

H thng cng s lin kt vi mt bin p i gim n mt gi tr thch hp cng nh lin kt vi cc thit b sau:



a) A.C. ON/ OFF switch

b) D.C. voltmeter 0-50V

c) D.C. charge ammeter of appropriate rating

d) D.C. discharge ammeter of appropriate rating

e) "Float" pilot lamp (blue), "Boost" pilot lamp (green), "Mains on" pilot lamp (red).

f) "Charge Failure" pilot lamp (amber), "Low Voltage" pilot lamp (amber), "Earth Fault" pilot lamp (amber).

g) Audible alarm

h) Rectifier fuse of appropriate rating

i) Charge failure monitor, low volt monitor, earth fault monitor

j) Boost/ Off/ Float selector switch

k) Auto/ manual charge selector switch

l) Facilities for testing the batteries and pilot lamps

m) Provisions of the remote alarm monitoring points. (Signal wiring from the panel to the field data gathering panel shall be done by B.A.S. Sub-Contractor):-

i) Battery High Voltage Alarm

ii) Battery Low Voltage Alarm

iii) Mains Power Failure Alarm

iv) Charging Failure Alarm

v) Earth Fault Alarm

n) Other components as required

a) Cng tc A.C. ON/OFF

b) Vn k D.C 0-50V

c) Ampe k sc D.C. vi gi tr thch hp.

d) Ampe k x dng D.C vi gi tr thch hp.

e) "Float" n bo(xanh dng), "Boost" n bo (xanh l), "Mains on" n bo().

f) "Charge Failure" n bo (vng), "Low Voltage" n bo (vng), "Earth Fault" n bo (vng).

g) Chung bo ng

h) Cu ch chnh lu c gi tr thch hp.

i) B kim sot li sc, in p thp, li chm t.

j) Cng tc chuyn v tr Boost/Off/Float

k) Cng tc chuyn Auto/manual charge

l) Nhng thit b kim tra bnh c qui v n bo.

m) Nhng im kim tra bo ng t xa. (dy tn hiu t t n t tp trung cc d liu s c lp t bi nh thu B.A.S):

i) Bo ng Battery High Voltage

ii) Bo ng Battery Low Voltage

ii) Mt ngun Mains Power Failure

iv) Li ngun Sc

v) Li chm t Earth Fault

n) Nhng thit b yu cu khc.



The voltage level on normal and boost charging shall be adjustable by means of clearly marked controls situated inside the cubicle.

Essential requirements of the batteries and the charger shall be as described below.

3.27 BATTERY

Batteries shall be of high performance nickel-cadmium or sealed lead-acid type and shall be capable of supplying the standby and intermittent loads specified herein without deterioration under the environmental condition specified, with a constant voltage regulator connected to it as a float charger. Cells shall be of the nickel cadmium pocket plate type with a vent cap at the top.

Cell containers shall be of moulded translucent plastic of high impact resistance and be able to withstand continuously corrosion attack by electrolyte. The battery compartment shall be designed such that work performed on a battery in service shall not require circuit interruption.

Terminals and inter-cell connectors shall be of high conductivity corrosion-free material. Interconnection of rows of cells shall be in annealed copper bars of adequate cross section, suitably insulated.

The battery shall have a nominal output of 30V. The nominal cell voltage after rated discharge shall be not less than 1.1V.

On the failure of the mains supply, the battery shall be capable of supplying the connected load for 5 hours. At the end of the 5-hour period, the battery shall be capable of providing power to close and trip all the circuit breakers 4 times. The closing and tripping shall be made in an interval of 5 seconds. During the 5-hour period and at the end of the above closing and tripping duties, the terminal voltage of the battery shall be not less than 27V.

Mc sc bnh thng hay sc nhanh c th iu chnh c bng cch chuyn b v tr c vch du c t bn trong t.

Nhng yu cu cn thit cho bnh v b sc nh sau.

3.27 BNH C QUY

Bnh c tui th cao nh nickel-cadmium hay axit- ch kh phi c kh nng cung cp d phng lin tc cho ti nh d tnh m khng h hng trong nhng iu kin mi trng nht nh, vi mt b n p ni n n nh mt b sc ni. Mi ngn s l hc nickel cadmium loi bn mng vi mt np trn.

Nhng ngn cha phi l loi nha trong m c c bn cao v c kh nng chu c s n mn bi cht in phn. Ngn cha bnh c qui c thit k sao cho khi thc hin nhng cng vic cn thit trn bnh m khng lm gin on mch in.

im ni v cc u ni bn trong phi l loi vt liu chng n mn v c tnh dn in cao. Nhng mi ni bn trong mt ngn s c ti bi nhng thanh ng vi mt tit din v cch in ph hp.

Bnh in c in p ra thng l 30V. in p mt ngn bnh thng sau khi s dng c gi tr khng t hn 1.1V.

Khi ngun chnh b mt, bnh n phi c kh nng cung cp in trong vng 5 gi. Sau 5 gi, chng phi cn kh nng cung cp ngun ng v ct cc CB 4 ln. Thi gian ng v ct s cch nhau khong 5 giy. Trong sut thi gian 5 gi cung cp ngun lin tc hot ng ng ct cc thit b, in p 2 u cc ca bnh s khng nh hn 27V.



3.28 CHARGER EQUIPMENT

The battery charger shall be of constant voltage float type, suitable for use with the associated batteries. The charger shall be operated at 400/230V A.C. and shall comprise transformer rectifiers of adequate capacity for the conversion of A.C. to constant voltage D.C. for charging at the float and boost values together with the supply of the standing load specified. It shall be self-protecting against continuous overload and shall be suitable for re-adjustment to correct for aging of rectifiers and other parts.

The charger shall be of solid-state type with protection against voltage surges. The components shall be so rated and mounted as to ensure that under all operating conditions they shall not require replacement during the life of the equipment and require no or minimum pre-commissioning adjustment. The charging circuitry shall be so arranged that the failure of any component will not cause permanent damage to the batteries by overcharging.

The charger shall be housed in a suitable floor-mounted sheet-steel cubicle with lockable double-hinged front doors, and anti-vermin ventilation louvres.

The charger shall have a maximum current rating sufficient to meet a battery charging current in amperes, equal numerically to 7% of the battery capacity at the 10 hour rate. The charger on float charge performance shall be such that with the output voltage set with rated input voltage, frequency, and with 50% load, the output voltage shall not vary by more than +2% with any combination of the input supply voltage and frequency variations stipulated in the Specification and output current variation from zero to 100%. With rated input voltage and frequency, the charger output shall not be less than its rating in watts over the complete output voltage range.

The charger shall have a taper characteristic

3.28 CC THIT B SC

B sc s l loi c hng s in p tri ni, thch hp s dng vi cc thit b h tr khc. B sc hot ng vi ngun 400/230V A.C. v bao gm mt bin th chnh lu vi dung lng thch hp bin in p A.C sang D.C vi gi tr sc t do hay sc tng in p nhanh cng nh cung cp cho ti d phng. N phi c kh nng t bo v chng li qu ti v iu chnh trnh s lo ho ca b chnh lu v nhng phn khc.

B sc l loi bn dn c bo v chng in p nhiu. Cc thit b cng s c gi tr v c lp sao cho m bo tt c iu kin hot ng, chng s khng phi b thay th trong sut tui th ca thit b v yu cu khng hoc gim thiu s cn chnh trc. Mch sc s c lp t sao cho s h hng ca tt c cc thit b s khng lm bnh c quy b h do sc qu dng.

B sc s c t trong mt ngn bng thp vi sn lp thch hp, c bn l i c th kho c lp ca trc, c khe l chn thng gi chng cn trng.

B sc phi c gi tr dng ln nht ph hp vi dng sc trn ng h ampe, tng ng 7% dung lng bnh trong 10 gi. B sc s th hin nhng bin i nh l vi in p ng ra so vi in p ng vo, tn s, v vi 50% ti, in p ng ra s khng thay i qu 2% vi bt k s thay i tn s, in p ng vo c quy nh trong c tnh k thut v s bin i dng ng ra t 0- 100%. Vi gi tr tn s, in p ng vo, ng ra ca b sc s khng t hn gi tr ca n tnh bng watt trong ton b khong in p ra.

Trn b sc s c mt ming dp vi phn ui



booster charging facility, which shall be selected automatically or manually. In the event that the batteries are subjected to a heavy discharge, automatic changeover from float to boost charge (and vice-versa) operation shall occur as necessary to restore the batteries to the fully charged condition.

The charger shall maintain the batteries at a normal fully charged state, based on the following criteria:-

a) A constant voltage float-charge on the batteries shall be arranged such that, at below gassing level, the need for boost charging of the batteries is reduced to rare intervals and maintenance requirements minimised. The float-charge rate shall give a fast recharge to approximately 75% of the batteries' capacity within six hours with minimum electrolytic loss.

b) Without heavy discharge, the float-charge rate shall also be such that battery electrolyte, at the ambient temperature specified, shall not require topping up at an interval less than once a year.

c) After a heavy discharge, the time to restore the batteries to the fully charged condition shall be no more than 8 hours. The booster-charge voltage shall be limited to a maximum value which will not reduce the life of the batteries.

d) If the batteries require occasional discharge-charge cycling to condition the electrolyte, the manufacturer shall inform and make provision for this in the charger.

H.R.C. cartridge fuses shall be provided to protect and isolate individual control modules or boards and outputs from the batteries and load. Screw-in fuse cartridges shall not be used in all L.V. and extra L.V. circuit.

A suitable surge suppressor shall be installed in

gim dn th hin c trng ca b sc, ci chn ch sc t ng hay bng tay. Nu bnh in buc phi sc nhanh, nu cn thit chng s i trng thi t sc chm sang nhanh ( v ngc li) bng mt b chuyn i t ng phc hi bnh n trng thi y hon ton.

B sc s duy tr bnh trng thi sc y da trn nhng tiu chun sau:

a) Hng s in p sc tri ca bnh c quy s c ci t di mc bay hi ca cht kh, ch sc nhanh ca bnh th uc ci t gim n mc gia v s duy tr yu cu gim n mc thp nht. Ch sc li nhanh ca bnh s c gi tr khong 75% dung lng ca bnh trong vng 6 gi vi s hao ht cht in phn l thp nht.

Khi bnh khng x nhanh, gi tr sc cng ch nh l cht in phn ca bnh. nhit mi trng xung quanh, khng cn thit sc y bnh t nht l mt ln trong khong mt nm.

c) Sau khi x nhanh, thi gian phc hi li y bnh s phi khng qu 8 gi. in p sc nhanh s c gii hn ti gi tr ln nht m khng lm gim tui th ca bnh.

d) Nu bnh in thnh thong c s dng chu k np-x, nh sn xut s c thng bo lm sn nh yu cu cho b sc.

Cu ch v loi H.R.C. s c lp bo v v cch ly board hay nhng mch iu khin v cho dng ra t bnh n ti. Cu ch loi bt vt s khng c s dng trong tt c mch L.V. v ph L.V.

Mt b kh nhiu thch hp s c lp trn c



both the input and output of the charger to prevent damage of the electronic components due to any external surge.

The charger shall also be provided with load over-voltage protection. On the output terminals to the load, the voltage shall be limited so as not to exceed 12V D.C. with any combination of standing load current and charger output voltage.

An approved charge fail relay shall be provided for the charger to detect failure of the D.C. output of the float (low rate) charger.

A relay shall also be provided to detect fall of battery volts below the low-rate value. The alarm shall be delayed by between 30 to 60 seconds and in the event of a failure in the delay circuit, an alarm shall be given instantaneously. The alarm shall have a sharp threshold (the voltage decay may be very slow, with high performance batteries on light. load) and take no more than 50 mA continuously.

Where the batteries are not earthed, means shall be provided to detect low insulation resistance of all wiring connected to the battery by means of a centre-tapped earth fault relay.

The earth fault relay shall operate when the insulation of the wiring connected to either pole of the battery drops to 50,000. When one pole of the battery is directly connected to earth then no more than 5 mA earth fault current shall flow. The continuous drain from the battery shall not exceed 10 mA. The relay shall provide three independent contacts for alarms.

The control circuit of the charger shall be of the solid-state type. Whenever it is necessary to step down the D.C. voltage for feeding electronic components, an A.C./ D.C. converter shall be utilized. If any series resistors are used instead for this purpose, they shall be adequately rated.

ng vo v ng ra ca b sc trnh gy h hng cc thit b in t do bt k s nhiu t bn ngoi no.

B sc cng s c lp b bo v qu p. Trn ng ra n ti, in p s c gii hn sau cho khng vt qu 12VD.C bng bt k s lin kt gia in p ng ra ca b sc v dng ti d phng.

Mt rle kim sot b sc thch hp s c lp t tm nhng li trn ng ra D.C ca b sc (nh l kim sot im ra c gi tr thp).

Mt rle cng s c lp t kim sot gi tr in p thp ca bnh. Tn hiu bo li s pht ra sau 30-60 giy, v khi trong mch bo li c s c th tn hiu bo ng s pht ra tc thi. Tn hiu bo ng s c mc ku nghe chi tai (in p tiu hao s rt nh, so vi bnh c thi gian s dng cao cho ti n) v tiu th lin tc khng qu 50 mA.

Ni m bnh c quy khng c ni t, th s c lp b d tm in tr cch n thp cho tt c dy dn c ni n bnh bng mt rle chm t.

Rle bo v chm t s tc ng khi cch in ca dy dn ni n cc bnh in gim xung n 50,000. Khi mt cc ca bnh tip xc trc tip vi t th dng chm t ln hn 5mA s chy qua. Dng x lin tc t bnh c quy s khng c vt qu 10 mA. Rle s cung cp n 3 tip im c lp pht ra tn hiu bo ng.

Mch iu khin ca s l loi bn dn. Nu cn thit gim in p cung cp cho cc thit b in t, mt b bin tn A.C/ D.C s c s dng. Nu s dng nhng in tr mc ni tip, chng phi c gi tr tng thch.



3.29 DEHUMIDIFIER

Dehumidifiers shall be self-contained units with laminated steel case.

They shall be equipped with automatic humidity control, dial adjustable, and shall have automatic drain trap.

The operation of the humidifier shall not cause any increase in the ambient temperature of the room.

The dehumidifier shall be capable of removing 16 litres or more of water per 24 hours from the air and shall operate from 230V 50 Hz single phase A.C. supply.

The Sub-Contractor shall be responsible for all pipeworks and pumps, if necessary, to discharge the water to the nearest floor trap or drain as directed by the Engineer.

3.29 B RT M

B rt m s l thit b t cha vi thng lm bng thp tm.

Chng s c trang b b kim sot m t ng, mt iu chnh c chia vnh, v c b x t ng.

Hot ng ca b rt m s khng lm tng nhit xung quanh ca phng.

B rt m c kh nng rt c 16 lt nc trong khng kh hay nhiu hn trong 24 gi v s dng ngun cp 230V 50 Hz mt pha.

Nh thu s chu trch nhim v nhng ng ng lm vic v bm, nu cn thit, x nc n l thot sn hay ng ng x th s c hng dn trc tip bi Qun l K thut.

Section 3 h.v Switchboard and Related Equipment

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Transcript of Section 3 h.v Switchboard and Related Equipment