Electrical Design

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lngenieurgesellschaft mbH M. Lebenyi M. Lebenyi M. Lebenvi APPROVED 0204 07 AREA CODE 4700 W. Horn W. Horn W.Horn CHECKED PTT CONTRACT No PTTIGAS131113145 PTS PROJECT No Rev C N. Hengen 0. Lorey H. Fiedler PREPARED PO-o20?0 C S 13\'\\#7 1-4-0104 0 7-4700-002 Final For Approval Issued for Comment

REVISION C B A REV. NO. 24-Jan-2003 06-Jan-2003 16-Dec-2002 DATE


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'This specification covers the general requirements, design, supply, installation and commissioning of complete electrical facilities of the compressor station


For specific requirements not described in this specification, reference should be made to the Regulations, Codes and Specifications listed in section 2 of this specification and all construction drawings,,

The electrical system will include the following items: Electrical power distribution

Lighting systems Grounding systems

D C System for Cathodic Protection and switchgear TripIClose actuation



The electrical materials and instruments shall conform to the latest edition of following regulations, standards and codes:

Recommendation for rotating electrical

machinery, motors and generators IEC 43 1

Recommended practice for electrical installations at the gas compressor station

Recommended practice for classification of location for electrical installation at gas facilities ANSllNEC C 1

Safety rules for installation and maintenance of

electric supply and communication lines NEClANSIC2.2 Standard for cross linked polyethylene

insulated wire and cables IPCEAS-66524

Lighting intensities IEC




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0 National electric code I EC

Switchgear IEEE


Transformer IEC

Institute of electrical & electronic engineers IEEE

Electrical equipment and materials shall comply preferably with relevant international standards Electrical equipment and materials may comply with other national

standards provided they are approved by recognised national certifying authorities of the country of origin and approved by the Company.



The scope of work of the supplier of the equipment includes the following as a minimum:

Design, engineering of the system and project management

0 Manufacturing

Factory acceptance test Shipping

Supervision during installation of the system


Start-up, pre-commissioning and commissioning

Supply of commission spare parts Documentation




All equipment shall be suitable for operation


a hot, dusty and humid environment, subject to monsoonal rains

For basic design date refer to Specification

E4 0204





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Physical protection

Electrical equipment will be installed indoors or outdoors, above or below ground, with or without additional protection as further detailed in relevant specifications for various types of equipment,,



Area classification shall be developed for installation based upon the requirements of "Recommended Practice for Classification of Locations for Electrical Equipment at gas compressors facilities", 199 xs or later edition Drawings shall be prepared indicating the classification and extent of each area and shall include reference to major structures and equipment contained therein All equipment which is considered a source of flammable liquid, gas or vapour shall be shown on the drawings Source shall be identified by equipment number, flammable materials handled, and


atmosphere group as per NEC

All equipment installed in hazardous areas shall be certified for use in the appropriate area classification and shall bear permanent indication from either BASEEFA, CENELEC or an approved testing laboratory in the country of manufacture. In general the equipment shall be protected by one of the following methods:


Ex i Intrinsically Safe


E x d Explosion Proof


Ex p Pressurized / purged Enclosure

.. Ex m Encapsulation


E x e Increased safety

Equipment meeting these standards may be installed in classified areas as indicated in the following table:

Equipment protection methods

Standard industrial equipment having enclosures suitable for indoor or outdoor locations as appropriate may be applied in unclassified (safe) areas

Ex e


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Whenever feasible electrical equipment should be installed in safe areas

Equipment for installation in classified areas shall be suitably certified by one of the following authorities:

American Equipment U L (Underwriter Laboratories)

German Equipment PTB ( Physikalische Technische Bundesanstalt )

British Equipment BASEEFA (British Approvals Service for

Electrical Equipment in Flammable Atmospheres)

French Equipment Le Ministre Du Developement Industriel et


Equipment of other Countries Such equipment may be accepted provided it has been tested and certified by any one above listed authorities



Single line diagrams shall cover all power and excitation circuits including metering and protective relaying One line diagrams shall be a separate set of drawings and may not be based on other types of drawings

The one line diagrams shall include: Major Equipment Ratings

Generators V, kW, PF, Xd, Xd"

Power Transformers

Circuit breakers



Phase, tap range, impedance BIL, (if arrestors), vector group,

Connections, grounding

Continuous A, interrupting MVA or

kA, momentary kA ( if different ) Continuous A, momentary kA,

(Spec symmetrical or asymmetrical)

Arrestors kV opening

Neutral grounding devices A (limit)


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Cable supplying power transformers Size and substation buses

Protective Relays Device number and number of


Loads Size, service, number

The principal voltage levels shall be as follows: Power Utilization

22 kV, 3 phase, 50 Hz, 3 wire Solidly Grounded Neutral 380 V, 3 phase, 50 Hz, 3 wire Solidly Grounded Neutral 220 V, 3 phase, 50 Hz, 4 wire Solidly Grounded Neutral 110 VDC

48 VDC, Ungrounded 24 VDC, Ungrounded

The electrical system shall be capable of handling the maximum expected plant loads continuously These expected plant loads shall be detailed in load summary schedules During starting of a motor, the voltage at its terminal shall not fall below


80% of motor rated voltage

Power cables shall be sized as per NEC requirements limiting the maximum voltage drop in the cable to 17% on motor starting, or 3% when running, whichever requires the larger cross section



i Electrical power for the facilities to be constructed may be derived from the existing

22 kV open air line via an additional transformer The dimension of this transformer rating shall be approx 80 % of the summary compressor station The whole equipment for connection to the existing 22 kV line shall be provided

Facilities unable to meet the requirements of Section 6 shall be provided with a new primary sub-station, power transformer and distribution switchgear The electrical sub-station shall be located in an area of the control building as close as possible to the plant area with which it is associated and shall comprise of the following :

Dead End Structure, Line Fuses and Protection 22 kVl380 V Distribution 'Transformer

380 V Distribution SwitchboardIMCC

220 V Lighting & Small Power Distribution Board 110 V Uninterruptible Power Supply





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All equipment should be suitable for continuous operation in a tropical environment, housed in a prefabricated, skid mounted, fully isolated, sheet metal enclosure

(except transformers) complete with all necessary standard and emergency lighting, power outlets, air-conditioning and fire detectionlprotection equipment The enclosure will be designed to prevent the ingress of sand and insects and to provide a clean cool working environment



Distribution transformers shall comply with Specification N o E3-020407-4700-112

Distribution transformers will be of indoor type for installation on concrete foundations (rolling tracks) in a suitable transformer room and inherent suitable personal protection

A separate oil pit shall be provided for each transformer Oil pits shall be filled with gravel and shall be of sufficient size to retain the quantity of oil in its associated transformer

Bus ducts shall not be used for secondary connection of transformers to motor control centres Such connections shall be by cables or in concrete trenches and entering the switchboard from below

Transformer sizing shall normally be 120% of the total motor operating load plus the lighting and electric heating loads, and shall also permit starting of largest motor with remaining normal connected load operating without secondary bus voltage drop exceeding 15% of normal

Transformers shall be provided with taps at: +I- 2,5% and +/- 5,0%



Switchboard I MCC shall be of the metal enclosed cubicle with multi-tier starter units for 380 V motors and shall be housed as indicated in the relevant section of this specification,,



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Electrical Design Manual


Motors shall comply with specification No. E3-020407-4700-119-Rev0 Motor windings shall be designed for the following voltages:

0,5 kW to 200 kW 380 V / 3 Phase , 5 0 Hz

below 0,5 kW may be single phase motor

All motors shall have "lock-off' type emergency stop buttons located adjacent to the motor


All power, control, lighting and instrument cables shall be manufactured in accordance with specification No -E3-0204 07-4700-120 and shall comply with the latest issue of the applicable IEEE or IEC specifications with respect to ratings and isolation All building or control wire must be constructed with 98% conductivity

( copper

Aluminium conductors shall only be used for overhead power installations Acceptable classes of conductor isolation are as follows:

Moisture resistant thermoplastic for wiring 600 Volts and below, Moisture resistant cross linked polyethylene for wiring 600 Volts and below, and PVC jacketed cross linked polyethylene for wiring above 600 Volts

Mineral isolation, 600 Volt rated, if copper sheathed and PVC jacketed Minimum acceptable isolation thickness between conductors and between conductors on sheath shall be 1,5 mm (0 06 in)

Isolation shall be fully resistant against petroleum products, weak acids and all alkalis, intense sunlight, moisture and abrasion from wind driven sand Isolation shall be rated for handling at -5 "C and for operation at +90 "C or better

Cable armour shall be either galvanised steel or corrosion resistant aluminium containing less than 0,4 % copper Armoured cable installed outdoor or underground shall have an outer thermosetting or thermoplastic jacket

Cable jackets shall be colour coded, with tracers as necessary, for ease of identification Colour code shall be as follows :

Power, Lighting and Miscellaneous Cables black or grey

Fire and Gas


Explosion Proof red

Fire and Gas


Intrinsically Safe red / blue trace


Flame Detection Heat Detection Smoke Detection

C 0 2 Dump System Controls Deluge Release Control Manual Fire Alarms Fire Pump Controls

light blue 1 orange light blue I green light blue 1 yellow red 1 orange red 1 brown red


yellow red 1 white

Use of coloured bands adjacent to the cable numbering, may be used as an alternative to coded jacketing

Wire and cable passing close to high temperature equipment and piping shall use isolation and jacket materials suitable for higher ambient temperatures expected The maximum permissible voltage drop in cables for normal operation shall be as follows :

Feeders to area sub-station 1 %

Motor branch circuits 3 % (continuous)

17 % (starting inrush)

Lighting branch circuits 2 % (from panel to furthest outlet)


Single Core Power cables shall have nonmagnetic armouring, which shall be bonded to the grounding system and shall be installed in trefoil formation with clamps suitably rated to withstand the applicable short circuit bursting force

All cables shall be rated adequately, with suitable derating factors applied for :

Ambient air temperature

Grouping arrangement of cables on a tray or cable rack Buried directly in the ground or ducts

Cable sizes for control and signal cables shall be as follows


Control cables 14 AWG ( 2,5 mm2 )

- Signal cables 1 6 ~ ~ ~ ( 1 , 5 m m ~ )

Thermal short circuit rating shall also be taken into account, consideration being given to maximum applicable fault clearance time possible


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Cables mounted above the ground

The installation of cables above the ground requires the utmost attention to neatness to improve the aesthetic qualities of the final installation, and consequently much thought should be given to cable positioning to minimise the number of crossovers. Where cables are run above grade they shall be securely fixed to suitably supported robust perforated galvanised steel cable trays

Cable shall be grouped according to voltage, and in minor cable runs specific trays shall be used for each group

Power I Lighting control cables shall not be mounted on same cable trays or racks as temperature compensating cable or air supply lines

Cable racks and trays shall be attached to steel supporting structures of building,


platforms or pipelines They shall not be supported from process piping

Cables shall be fixed in positions where they shall not be exposed to oil, direct sunlight or heat from other hot objects unless the cables and their accessories are specially designed to withstand the effect of exposure to oil and heat,

All cable racks and trays installed in open locations shall be fitted with sunshades to prevent overheating by direct sunlight

A minimum distance of 10" shall be maintained from all hot vessels, pipelines or other hot objects for all cable rack or tray,,

Cables shall be installed in such a manner as to minimise the effects in vibration of any equipment

Cables to individual consumers shall be installed on light duty cable tray, adequately supported between the main cable route and the consumer terminal box

Under no circumstances shall any cable be bent to a radius less than the minimum specified by the manufacturer, Straining of cables at cable glands shall not be permitted and cables shall run straight out of the gland for a minimum of 4" before beginning to bend,,

Each cable shall be individual as designated on the cable schedu!e, by means of unique identification markers Each cable shall be so identified at its point of origin and termination, at both sides of any penetration and at 30'0" intervals along its length


Cable trays should be assembled type, hot-dipped galvanised steel construction


either robust perforated galvanised steel cable trays or ladder type PTT PUBLIC


Cable tray fill shall not exceed 40 % of its cross-sectional area

Cables installed on top of horizontal tray shall be secured to it by means of nylon straps or equivalent material at intervals not exceeding 20 feet

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Bidding Documents Electrical Design Manual

Where vertical trays penetrate the floor or ground they shall be provided with covers for at least 6 feet above the floor or ground elevation, unless waived on Contractor's I

Client's drawings





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The cable tray system shall be grounded

Cable tray systems shall be electrically continuous and grounded at intervals not exceeding 75 feet


Cable Termination

All conductor terminations shall be by means of compression type solderless cable lugs, except control circuits and other small wiring which shall be wired to readily accessible clamp type terminal blocks

All cables shall be supported so as to ensure that no weight has to be borne by the terminations

Grounding conductors included within cables and metallic sheathing and armouring of cables shall be connected to the grounding system

Each terminal and connected wire or cable core shall be marked and identified with suitable plastic type ferrules, in accordance with relevant wiring diagrams

Terminal studs in transformer cable terminating boxes shall be wrapped with "Scotch" tape.

When the cables to motors are too large for the terminal box, they shall be terminated in a suitable junction box and a smaller cable used between the junction box and the motor as detailed in relevant cable schedules

Outdoor cable glands shall be provided with a seal to prevent the ingress of dust Glands in classified hazardous areas shall be of approved flameproof type


Particular attention shall be paid to the phase sequencing of power cable termination since subsequent alternation is difficult and time consuming




Two separate lighting systems shall be provided; a main system and an emergency backup system

Main L~ghfing

i Supply 230 VAC, 1 Phase, 2 wire, 50 Hz

ii Control



General area flood lighting shall be controlled by a single photo-electric cell


controlled multi-pole lighting relay The flood lighting can also be controlled manually

iii Control -. indoors

All indoor lighting shall be manually controlled with switches at convenient positions next to entrances of doors


Lighting shall provide the following minimum illumination levels in service as measured on the horizontal phase :


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Emergency Lighting

The emergency lighting shall be by fitting with self-contained battery units which shall automatically operate in case of mains failure and shall remain illuminated for a minimum of 60 minutes The number of fittings required shall be approx 25 % of the total fittings requirement for each of the respective areas and shall be located at manned control panels, exits, and areas which will cause personnel safety hazard on loss of main power

The laws and standards of the country must be strictly adhered to Electrical Design Manual

5 1 75 100 75 20 1.13. 1.14. 1.16. 1.16.1. 1.16.2. 1.16.3. 1.16.4.

Lighting Distribution boards

" "

Separators General Areas

Unit and Central Control House ( or rooms )

Console desk area Panel front

Panel interior

Generally, lighting distribution boards shall be suitable for 230 V, 3 phase, 4 wire 50

Hz operation, Branch ( outgoing ) circuits shall be of the single pole, phase protected by fuses or miniature type circuit breakers rated at 15 amps One spare branch circuit shall be provided for every five circuits used Each circuit shall be loaded only up to approx 10 Amps to leave at least 25% spare capacity

Normally, lighting distribution boards shall be installed in control rooms

Where it is necessary to locate lighting distribution boards out door they shall be installed in safe areas They shall be of the weatherproof type and be under a sun canopy


Lighting Fixtures

Fixtures shall be of the type specified below :

General Area Lighting ( Outdoors )

On-plot high pressure sodium floodlighting must be supplemented by fluorescent lights where necessary

General Lighting ( Indoors ) Fluorescent fittings must be ceiling mounted

All fittings installed outdoors shall be of a weatherproof type and suitable for use in the respective hazardous areas

Fittings shall be spaced to provide uniform illumination as far as possible

Illumination shall be provided for all non-self-illuminating gauges and instruments Lamps that are adversely affected by transient voltage disturbances shall be kept to


a m~nimum If used for main lighting, they shall be adequately interspersed with

lamps that are not affected They shall not be used for emergency lighting

Discharge type lamps in operating areas which incorporate rotating equipment shall be supplied from more than one phase to minimise stroboscopic effects


Fittings shall be so connected and located that the maintenance and the replacement of lamps can be achieved safely and conveniently by one man

A common grounding system is necessary All connections and links shall be of connector type,,

The neutral of all power systems shall be solidly grounded at the transformer secondary For further details please refer to "Cabinet Grounding Diagram", J-3- 0204 07-4700-007,

Equipment Grounding

All non-current carrying metallic parts of the facility shall be directly grounded by connection to the grounding system



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Consultancv Services for

neutral grounding electrodes



All structures, vessels, tanks, etc shall be connected to the main grounding system

The resistance of grounding system to the general mass of earth shall be as low as feasible, but shall never exceed 2 ohm at any point on the grounding system,,


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Electrical Design Manual

Main plant grounding system shall be least one ring system of 210


AWG (70 mm2) minimum PVC sheathed stranded copper grounding

conductor connected to the existing grounding equipment Branch connections to motors or small equipment shall be 4


AWG (16 mm2) min green PVC sheathed stranded copper conductor,





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Ground rods shall be % " diameter copper clad steel ground rod of suitable length to achieve the desired resistance to earth

Lighting and static earthing


the recommendations of ANSI C 51, API and NEC Grounding and bonding for lighting and static protection shall be in accordance with

Main ground system may be utilized for grounding and bonding required for lighting and static grounding

Installation of grounding system

The grounding system shall be designed on the ring principle with interconnection of conductors to equipment as necessary The ring shall be connected to the main ground system via earth bars and shall be green PVC insulated stranded copper min,

210 AWG ( 7 0 rnm2 ), branch conductors to equipment shall be a minimum of 4-AWG ( 16 m m 2 ) ,

In general, grounding conductors shall be run on main cable routes

All underground cable connections to the ground ring shall be of the thermo weld type or similar, and each joint shall be taped

Vessels shall be provided with lugs for ground connection Ground cables shall be bolted to lugs with solderless connectors Vessels having cathodic protection at the bottom shall not be connected to the main ground system to avoid affecting the efficiency of the cathodic protection system

Electrical equipment grounding shall be by means of bolted connections Equipment holding down bolts shall not be used at the grounding points

Cable armour shall not be used as the only means for the return of ground fault currents and shall nevertheless be grounded through the gland connection to the grounded equipment



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Connections between main grounding systems and electrodes shall be arranged so that easy inspection, maintenance and testing of individual electrodes will be possible

Cable armour of single-core power cables shall be grounded at both ends and at any splice



Sub-station Alarms

Bus tie alarms shall be provided as follows:

For each secondary-selective substation, to give abnormal indication whenever the breaker is closed or not in the operating position

For each spot network substation, to give abnormal indication whenever the bus sectionalizing device is open or not in the operating position,, For the two incoming circuit breakers or each spot network substation, a single alarm shall be provided, giving abnormal indication whenever either breaker is open or not in operating position Transformers rated 500 kVA and larger shall be provided with an alarm as follows:

The alarm shall be actuated by contacts in the liquid temperatule thermometer and shall give abnormal indication whenever the transformer reaches its maximum self cooled operating temperature as indicated by the thermometer

An alarm for each transformer with 2 float Buchholz relays is to be actuated by slow gas accumulation

Transformer alarms shall also be provided for differential relaying Switchgear control alarms shall be provided as follows:

Control battery charger alarms as listed below for each sub-station control battery

o Loss of an AC battery charger The detecting device shall be connected to the load side of the protective device or switch closest to the charger in the supply circuit

o Low battery charger DC output voltage o High battery charger DC output voltage

o Low battery voltage



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ground detector

One alarm relay shall be provided to monitor the trip circuit for each DC

controlled circuit breaker not controlling a motor All alarms shall conform to the following:

Plaster units and relays used in annunciator cabinets shall be of plug-in type,

Alarm systems shall be fail-safe type and utilizing normally closed alarm contacts

Annunciators may be of solid state type and of modular construction Acknowledge and lamp test switches shall be provided for each annunciator cabinet

Motor alarms

Motor alarms shall be provided as shown below, Alarms shall be located in the control room unless specified otherwise,



Alarm function I Alarm r e w i r e d for motor I Alarm actuated by


having Bearing high temperature

Winding high temperature Winding high temperature

Winding high temperature ~ -

Air ( or Gas ) low pressure

Motor winding high temperature alarms shall be set to operate when the normal or anticipated motor load is exceeded and before the overload relay setting is reached

Bearing temperature relays or detectors

Resistance temperature detectors

Winding temperature detectors (thermistor)

Alarm thermal relay in motor




Operating sequence of "motor off' alarm shall be:

Bearing temperature relay contacts ( A single alarm can be provided to actuate if either or both relays operate )

Contacts in winding temperature indicating controller

Winding temperature detector contacts Alarm thermal relay contacts


Pressurized motor enclosure, or pressurized commutator or slip rina enclosure

Motor running


light off and horn silent

Motor shutdown


light on steady and horn silent

Motor shutdown by other means


light on or flashing and horn sounding

Pressure sensing device located on high pressure side if air ( or gas ) supply line ( as

close to the ~ressure reducina device as


When specified


practical )

Auxiliary contact of motor contiol ( A second

contact of motor stop button shall prevent operation of alarm when the motor is shut own at its control station )


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Alarm for emergency valve motor actuators

An alarm shall be provided for each remote bus supplying motor actuators for block valves used in emergency isolation or shutdown and liquid pull down or vapour blow down service The alarm shall supervise bus voltage and shall be actuated by contacts of a normally energised supervisory relay at the valve bus and shall operate on loss of voltage The alarms shall be located in the control room



The fire fighting system shall come into play when the fire alarm system has been activated The fire alarm system and the fire fighting system installed by the Contractor shall work effectively and in conjunction with each other,


Receptacles or convenience outlets in process buildings shall be provided, enabling a 10 m extension cable to provide coverage in all areas as approved by the owner Receptacles on convenience outlets shall be provided adjacent to all outdoor coolers Receptacles or convenience outlets in non-processing buildings shall be provided to give adequate coverage in all areas as approved by the owner

Receptacles or convenience outlets above the counter in a kitchen area shall be split receptacles fed from a dedicated double pole lighting panel circuit

Mounting Heights

The mounting height of equipment and I or components shall be from finished floor level to the centre of the equipment and 1 or components

Light and control switches for building or room auxiliary devices shall be located on the latch side of the door



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All CONTRACTOR correspondence, documents, certificates and drawings shall be in the English language Fur further details refer to "General Specification for Electrical, SCADA, Instrumentation and Telecommunication", Chapter 10







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