Electrical Instrument Interface Philosophy

8/16/2019 Electrical Instrument Interface Philosophy

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INSTRUMENTATION SPECIFICATIONSECTION-IV

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SECTION-IV

ELECTRICAL INSTRUMENT

INTERFACE PHILOSOPHY


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INDEX

SR.NO. TOPIC PAGE

1 INTRODUCTION 32 ABBREVIATIONS 3

3 POWER INTERFACES 4

3.1 INSTRUMENT POWER SUPPLIES 4

3.2 LIGHTING SUPPLY/ANALYSER HOUSE SUPPLY 4

3.3 PACKAGE UNIT SUPPLY 5

3.4 ELECTRICAL HEAT TRACING & LO HEATERS CONTROL 5

4 CONTROL & MONITORING INTERFACE 5

5 MANAGEMENT SYSTEMS 6

6 E&I PLANT DESIGN INTERFACES 8

7 EARTHING 8

8 AREA CLASSIFICATION 10

9 I/O INTERFACES CONTROL DOCUMENT 10

10 MOTOR OPERATED VALVES (MOV’S) 10

ATTACHMENT

ANNEXURE-I, INSTRUMENT/ELECTRICAL INTERFACEDATABASE


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1.0 INTRODUCTION

This Electrical and Instrument interface specification defines the basic division ofresponsibilities between the two disciplines and involves both specialists engineering as

well as design functions.

In addition, this specification indicates how to organize the different interfaces.Thedefinition of the split of work and division of responsibilities as outlined shall be followedunless specific circumstances dictate otherwise. These deviations shall be properlyrecorded and routed as job instructions within the discipline’s task forces for each projectwith approval of OWNER. It is the responsibility of both the E&I lead engineers ofBIDDER that the procedures as described in this specification are followed.

Interface control documents shall be prepared by the agreed responsible discipline ofBIDDER for each interface activity (power supplies, process I/O’s, etc) at the start of theproject. These interface control documents shall be maintained, updated and

communicated by the agreed responsible discipline in pre-planned intervals during thedevelopment of the project. This shall be approved by OWNER before finalization.

2.0 ABBREVIATIONS:

The following abbreviations are used in this specification:

AC = Alternating CurrentDC = Direct CurrentDCS = Distributed Control SystemE = ElectricalEMC = Electro Magnetic CompatibilityDCS = Emergency Shutdown System or Programmable Logic ControllerFO = Fiber OpticHV = High VoltageI&CS = Instruments & Control SystemsIFC = Interface Cabinet AnalogILD = Instrument Loop DiagramIMCS = Integrated Motor Control SystemI/O = Input / OutputIRC = Interposing Relay Cabinet (Digital I/O interface)LV = Low VoltageMC = Marshalling CabinetMCC = Motor Control CentreMOV = Motor Operated ValvePA = Public Address SystemP&ID = Piping & Instrumentation DiagramPMS = Power Management SystemSCADA = Supervisory Control And Data AcquisitionUPS = Uninterruptible Power SupplyVSD = Variable Speed Drive System


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3.0 POWER INTERFACES

3.1 INSTRUMENT POWER SUPPLIES3.1.1 In general the instrumentation systems and external powered instruments

requiring a supply > 50 V AC, BIDDER’s Electrical group shall provide thepower supply system dedicated for BIDDER’s I&CS group, includingemergency or standby equipment such as generators and UPS systems,power distribution boards and safety switches. However, in this case thisshall be tapped off from the main TDI plant control room building UPS

ACDB, which is located at @ 1 km away from the proposed locations.3.1.2 The various feeders of 110 V AC UPS supply from UPS ACDB located at

main TDI plant control room located 1 km away from the proposed siteshall be available in required qty with required amperage. The detailengineering of cable size, cable tray lay out and routing, procurement ofcable/cable trays and laying, etc. shall be by BIDDER.

3.1.3 Power supply distribution panels at central cabinet room for both

system/non-system power shall be the responsibility of BIDDER I & C3.1.4 In case sizing of power supply cable > 2.5 mm2, engineering, design andsupply shall be by BIDDER Electrical. The information and requirementsfor all BIDDER I&CS users for which BIDDER Electrical shall provide theelectrical power, shall be communicated by BIDDER I&CS to BIDDERElectrical by means of the “I&CS power supply interfaces list”.

3.1.5 Bidder shall ensure 110 V AC -1% & +2% at 50 Hz -3/+1 Hz qualitypower supply at Central Cabinet room from OWNER’s main TDI projectcontrol room UPS/ACDB. Further distribution for DCS shall be by sub-vendors. However, while designing instrumentation load in instrumentsystem PDBs from the UPS ACDB feeders, care shall be taken to ensurethat the max. capacity of each of the mains incomer feeder from UPS toInstrumentation shall be with max current rating of 10% of the UPScapacity in total amperage, at 110 V AC. Also all instrumentation loadsshall be catered via two diff. redundant feeders from two different busesof UPS ACDB.

3.1.6 For field instrumentation requiring 110 V AC, this shall be 110 V AC -2%& +1% at 50 Hz -3/+1 Hz at field devices (wired from centrally locatednon-system UPS PDB from central cabinet room only), including all cabledrops. The same UPS ACDB bus redundancy philosophy shall befollowed for all field instrumentation loads also. However, the completeinstrumentation system, including DCS/DCS , Field instrumentation andvarious package unit systems, shall be designed to run from 90 V AC to120 V AC at 50 Hz – 3/+1 Hz.

3.1.7 UPS power supply (110 V AC, 50 Hz) for whole instrumentation systemshall be equipped with half an hour battery back-up source as a minimum,for safe shutdown of plant, in case of total power failure.

3.2 LIGHTING FOR INSTRUMENTS /PANELS/ANALYSER HOUSES:

3.2.1 230 V A.C. Lighting for Level Gauges and various local panel as wellcomplete lighting of central cabinet room, central control room and centralengineering room shall be included in the “E / I&CS power supply


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interfaces list” with a reference to the level gauge tag number for whichthe lighting fixture is required. This shall be by BIDDER Electrical.

3.2.2 For level gauge, supporting bracket (part of level gauge assembly) andfixture specification is the responsibility of BIDDER Electrical.

3.2.3 Engineering, design and supply by BIDDER Electrical3.2.4 Distribution boards, if applicable, shall be located on the outside of theanalyzer house and shall be suitable for hazardous area classification ofthe plant. However for each analyser, the individual 110 V AC UPSsupply cables (in required sizes) will be laid from central cabinet roomlocated non-system UPS PDB by BIDDER I&C. Instead of laying 3 corepower cable from central control room located non-system UPS PDB toeach analyser, there shall be 2 core cable for each analyser. The finalsafety earth cable in redundant loop format from each analyser shall bebrought to a common safety earth pit located near control room forinstrumentation safety earth purpose. These earthing cables from eachanalyser houses, local panels, etc. to control room safety earth pits shall

be redundant.3.2.5 No UPS supply shall be provided to analyzer house, local panel for any ofthe instruments by BIDDER Electrical, directly from MCC. These shall belaid from the various UPS non-system PDB panels, located at centralcabinet room by BIDDER I &C, as per requirement.

3.2.6 For Electric motor operated valves, position switches shall be connectedto DCS via Electrical / Instrument interface panel (IRC) via interposingrelays only. Hence from MOV all the signals including torque switches,limit switches, etc. shall be wired to MCC and from MCC, the required on-off indication limit switches signals shall be wired to instrumentationsystem for indication/control/logic purpose to I&C. Hence it is theresponsibility of BIDDER Electrical including supply of cables, glands,terminations, etc. from field MOV to MCC and MCC toelectrical/instrument interface cabinets.

3.2.7 Power supply to these MOV’s is also the responsibility of BIDDERElectrical.

3.3 Power supply to PACKAGE UNITS

3.3.1 This shall be provided by BIDDER I &C from the central cabinet roomlocated non-system UPS PDB panel located at only one location to eachof the package units in the field. Further sub distribution shall be carriedout inside the package unit by package unit vendor.

3.3.2 230 V A.C. power supply required for non-instrument purpose shall beprovided by BIDDER Electrical to all package units, directly from MCC inpanel shed lighting, shelter illumination, etc. However, local instrumentpanel inside illumination shall be by BIDDER I&C, which will be wiredform central cabinet room located 230 V AC utility PDBs by BIDDER I&C.

3.4 ELECTRIC HEAT TRACING & LO HEATERs

3.4.1 Electrical heat tracing power supply shall be provided by BIDDERelectrical from MCC. This refers to process pipe line/equipment heat


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tracing, etc. For analyser sample tube heat tracing, etc., it is BIDDER I&Cresponsibility to provide 110 V AC UPS supply for sample heat tracingline from centrally located non-system UPS PDB.

3.4.2 Various Lube oil heater circuits, in general, shall be controlled by DCS by

BIDDER I&C. For the purpose, there shall be separate and dedicatedLube oil level and temperature transmitters installed on the LO tank.3.4.3 LO heater shall automatically start and stop from DCS interlock/Logic on

Low LO temperature and High LO temperature/ Low LO level,respectively, via two separate DCS DO for auto start and process trip, viainterposing relays in IRC driven by DCS Logic.

3.4.4 Additionally, there shall be manual start and stop facilities from DCSgraphic as a soft target. This soft target will actuate a DCS DO, which willbe wired via IRC panel located interposing relays to MCC for start andstop of LO heater manually.

4.0 CONTROL AND MONITORING INTERFACES

4.1 The E&I interface point for process and safeguarding systemsmeasurement, monitoring, control and protection I/O’s is the IRC and/orthe IFC which shall be located in the central cabinet / marshalling roomwithin I&C premises.

4.2 The IFC will be used for analogue signals (e.g. VSDS). From this panel,all 4-20 ma signals shall be wired to relevant I&C DCS marshallingpanels.

4.3 Since there shall not be any RTD or T/C type input cards in DCS/DCS ,all Motor bearing/winding related trips shall be realized by BIDDERElectrical via their MCC SCADA. Only the redundant softwarecommunication link from MCC SCADA to DCS shall be made available toI&C for making all such RTD and T/C real time indications/alarmsavailable to DCS operator on graphics. Hence there shall not be anymotor bearing/winding trip related hard wired signal exchange betweenDCS and DCS and DCS to MCC.

4.4 Engineering, procurement and laying of cables and all termination fromMCC/Field Motors to MCC SCADA, logic realization in SCADA withsequence of event reports, etc. shall be carried out by BIDDER Electricalfor all these signals.

4.5 All potential free/dry contacts for pump / motor running indications, MOVopen/close limit switches, etc. from MCC/SWB or VSD panels fromelectrical shall be wired to IRC via interposing relays and by BIDDERElectrical, including design, procurement and installation/laying of variouscables between MCC/SWB/VSD panels to IRC. IRC panel shall be of twotypes, i.e. DI IRC, which will accept all input signals to DCS wired fromMCC via interposing relays and the DO IRC which will provide various potfree digital output contact from DCS to MCC via interposing relays. Therelays in IRC for interposing purpose shall be by BIDDER I&C. All RUNsignals shall be hard wired between MCC and DCS. The redundantsoftware communication link between SCADA and DCS shall be used tomonitor various other signals like motor trouble, motor fault, ready-to-startsignals which are not used in control or interlock/logic by I&C in DCS. If


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any of these signals is used in control, interlock / logic or decision makingpurpose at DCS, the same shall also be hard wired from MCC to DCS.

4.6 All Digital output commands from I&C DCS systems for various purposelike Motor Trip/Auto-Manual Command( if used), Emergency Stop, etc.

shall be wired from respective DSC panels to IRC via interposing relaysby BIDDER I & C.4.7 All Auto/Manual switches shall be configured in DCS as soft targets on

DCS graphic accessible to operator with dynamic status. The Auto/Manual logic shall be realized in DCS along with other processparameters and/or running pump/motor run signals. The auto startcommands generated from DCS DO shall be hardwired to MCC viainterposing relays located in IRC. Hence no field LCS by BIDDERElectrical shall be with A/M switches. The normally energized status ofrelays shall be maintained in normal condition and when relay gets de-energized, auto start command shall be sent to MCC from DCS.

4.8 All Digital output commands from interposing relays meant for Electrical

MCC/SWB/VSD panels, etc. from IRC shall be accommodated in IRC.They shall be wired from IRC panel to MCC/SWB/VSD panel by BIDDERElectrical. All cables shall be designed, procured and laid by BIDDERElectrical. The normal energized status of DO relays/Process trip willkeep the pump/unit / section in running condition. On actuation of trip, thede-energized status of relay shall trip the pump/motor.

4.9 All IRC/IFC panels shall be of standard RITTAL make panels with1200mm (W) x 800mm (D) x 2100 mm(H) size, with RAL7032 color andshall be located at central cabinet room within the premises of I & C. It isthe responsibility of BIDDER I & C

4.10 All cabling between the IRC/IFC and MCC/SWB or other electricalcontrol panels (i.e. VSDS panels), field Motors, etc. is the responsibility ofBIDDER Electrical. The multi pair cables shall be separate for DI and DOexchange between MCC and DCS.

4.11 The measurement of power factor, frequency, speed, power consumptionand other typical electrical signals to be processed / handled ininstrumentation systems is the responsibility of the BIDDER Electricaldiscipline. I&CS will be responsible for incorporation of thesemeasurements into their system(s) from the interface point (IFC) torespective DCS /DCS panel. Measurements shall preferably be presentedby BIDDER Electrical as isolated analogue signals of 4-20 mA DC, or thismay be via Electrical SCADA redundant software communication link tocentral DCS, if such information are meant only for information purpose inthe DCS.

4.12 The monitoring and alarms annunciating associated with motors,switchgear, transformers and any other electrical equipment, which are tobe, annunciated on instrument panels and/or in I&CS are theresponsibility of BIDDER Electrical. BIDDER I&CS will be responsible forincorporation of these alarms into their system(s) from the interface point(IRC) or via software communication link between MCC SCADA andDCS.

4.13 BIDDER I&CS will be responsible for the detailed control, alarm,safeguarding requirements as shown on the P&ID's and passing all


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signals required for electrical control to the interface point as detailed foreach project.

4.14 BIDDER I&CS shall include the tag number on the interface document.4.15 Instrument Loop Diagram shall show the complete loop inclusive a

reference drawing number with respect to the electrical wiring up to thepoint of interface, i.e. IRC/IFC.4.16 For all pumps/motors, emergency stop command, BIDDER I&C shall use

a Mushroom Push Button with key lock, installed on Operator console.This buttons shall operate a 24 V DC interposing relay located in IRC.The potential free contact from these relays shall be wired to relevantMCC/SWB/Motors at Electrical Substation by BIDDER Electrical forstopping those motors. The other spare contact of such relay from IRCshall be wired by BIDDER I&C as a feed back to DCS as digital inputs totheir system for registration of pressing of push buttons with alarms onDCS and DCS graphics.

4.17 This emergency push buttons shall be in addition to any Trip/Auto stop

contact generated from DCS interlock from I&C System. In this case thetwo contacts (Em. Stop and process trip) shall be wired toMCC/SWB/Motors by BIDDER Electrical in their protection circuitry inseries.

4.18 In genral, remote start from Operator Console from Central Control roomis not envisaged for any Motor/Equipments. These shall not be provided,unless process group requires such facilities for a few of very criticalequipments, which will be decided during detail engineering.

5.0 MANAGEMENT SYSTEMS

Motor management and power management system ("intelligent" or“smart” switch gear) are the responsibility of BIDDER Electrical. Sincethese systems will be integrated with Distributed and/or Other controlsystems (i.e. DCS) via redundant software communication link, closecoordination and exchange of data and protocol agreement shall beestablished between the BIDDER E&I. The SCADA being designed,procured and implemented by BIDDER Electrical shall have the followingminimum hardware / functionality for its interconnectivity with centralDCS.

a. An isolated 2 Wire RS485 Serial Communication Link as anInterface ( Modem , over RS232C or current loop interfaces are notacceptable)

b. A proper communication media like twisted pair, screened/shieldedcable laid between Electrical and Instrument cabinet room.

c. MODBUS RTU protocol with complete memory map, configurationdetails, etc.

d. The scan time shall be better than 2 to 3 seconds for transferringall parameters of SCADA to DCS.

e. Electrical System/MCC SCADA shall be integrated with centralizedDCS. This shall be integrated with centralized DCS located at


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central control room with one way information exchange purpose inDCS (from MCC to DCS). The communication link betweenSCADA and DCS shall be over redundant serial RS485 interfacewith MODBUS protocol. There shall not be daisy chain

configuration on RS485 serial link between SCADA and DCS. OneSCADA shall be connected with one dedicated RS485 dualredundant serial link with DCS. No other RS485 devices shall beclubbed on this serial link.

f. The DCS, being a master time keeper on the entire plant widenetwork for uniform time stampings, the MCC SCADA shall also besynchronized with DCS time via NTP and GPS system via suitableinterface with hardware firewall.

6.0 E&I PLANT DESIGN INTERFACES

6.1 CABLE TRAY/LADDER / TRENCH ROUTING

6.1.1 Each discipline of BIDDER is responsible to provide the required input ofthe cable tray / ladder routing. The coordination within various otherdepartment of BIDDER like Piping, Civil, Structural and Pipe-support withrespect to main tray/ladder routing (e.g. space management, roadcrossings etc.) will be done by BIDDER Electrical for both disciplines.Underground/trench cables routing is not allowed.

6.1.2 An overall tray/ladder drawing (study) shall be prepared by BIDDERElectrical, with input from I&CS and will clearly indicating the following:

a. Tray/ladder routes, including termination points of runs, space andsegregation requirements including spare capacity

b. Elevations (for trays), Road crossings where applicablec. Segregation required between I&CS and Electrical cable

tray/ladder.

In generala. All high voltage cables carrying Electrical control voltage

signal/current shall be routed in separate ducts/trayb. All low voltage instrument signals like Run indication ( carrying 24

or 5 V DC interrogation voltage from DCS), low voltage electricalsignals like VSD 4-20 ma input/outputs, etc. shall be laid in aseparate tray/duct

c. All communication cables, PA system audio cables, telephonevoice cables, Fiber optic cables shall be routed through separateduct/trays

6.1.3 All the ducts/cable trays between instrument central cabinet room andelectrical substation/MCC room shall be sized in such a way to have 50%spare capacity for future use.

6.1.4 All main cable ducts between MCC and Central cabinet room shall bemin. 5 MM thick GI MOC duct with 3 mm thick SS304 MOC closed coverand all trays shall be either ladder or perforated tray of aluminum MOC.


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6.1.5 All MCC cables from MCC to central cabinet room shall be brought insidevia separate dedicated MCT frames the MCT blocks which will beidentified as an Electrical MCT. The low voltage and high voltage MCTblock segregation shall be maintained via separate entries of MCT blocks.

7.0 EARTHING

7.1 The main earthing, involving static earthing, protective earthing, lightningprotection and instrument earthing systems are the responsibility ofBIDDER Electrical.

7.2 The provision of earthing facilities on and within instrument equipment,instruments and any specific shielding requirements are the responsibilityof BIDDER I&CS. However necessary earth pits shall be provided byBIDDER Electrical as per the requirement of BIDDER I & C. For thepurpose BIDDER I&CS will provide an instrument earthing philosophy

and relevant typical earthing block diagram to BIDDER Electrical.

8.0 AREA CLASSIFICATION

8.1 This is the responsibility of the BIDDER Electrical discipline in closecoordination with Process. Area classification schedules, layouts and ifrequired sections will be prepared, from which both BIDDER E and I&CSdisciplines shall obtain the material selection requirements to ensuresuitability in the specific areas. However, as far as instrumentation isconcerned, the overall concept of all field instrumentation execution shallbe for general purpose instrumentation without any explosion protectionbut with weather protection to IP65 as a minimum.

9.0 I/O INTERFACES CONTROL DOCUMENT

9.1 A common database will be filled with information from BIDDER I&CS,BIDDER Electrical and BIDDER Process Group, based on variousprocess requirement, facilities and interlock/control necessity. Aconsolidated format is attached herewith as Annexure-1.

10.0 Motorized Valves / MOVs:

10.1 To the extent possible, the MOV shall not be used in the plant. However,if the requirement can not be avoided, it shall be the responsibility ofBIDDER Electrical for all type of procurement, erection, commissioning,power supply provision, laying of necessary cables from Substation andfinal operation, testing and maintenance of the same shall be carried outby BIDDER Electrical. The body/bonnet and trim MOC and otherspecifications/ construction of MOV shall be as per mechanicalspecification of this ITB.

10.2 At few locations, if MOV is equipped with various position sensors, theseshall be SNAP action type micro switches. These shall be wired from fieldto MCC by BIDDER Electrical and from MCC, via Digital Input interposing


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relays located in IRC, the same shall be either given to DCS, if used ininterlock/logic. If these switches are used only for indication purpose inDCS, the same shall be brought to DCS via MCC SCADA over softwarecommunication link.

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Electrical Instrument Interface Philosophy