7.ELECTRIC POWER SUPPLY

7.00.00  ELECTRIC POWER SUPPLY

 

 

7.01.00  The  requirements  of Electric Power Supply  system  are

 

         specified  herein on system basis. The contractor  shall

 

         be   fully responsible for engineering and furnishing  a

 

         complete and operational system fully meeting the intent

 

         and   requirements  of  this  specification  and   owner

 

         approved   drawings.  All  equipment   and   accessories

 

         requires  for  completeness  of  this  system  shall  be 

 

         furnished   by   the  contractor   whether   these   are

 

         specifically   mentioned   herein  or   not.   All   the 

 

         equipments and sub-systems offered shall be from reputed 

 

         experienced    manufacturer.   All   system    cabinets,

 

         enclosures & distribution boards shall be  manufactured,

 

         assembled, wired and fully tested as a complete assembly

 

         as  per the  requirements of this specification  at  the

 

         manufacturer’s works.

 

7.02.00  The  power supply system shall be designed to  meet  the

 

         electric  power  requirements  of  various  C&I  systems

 

         including  DDCMIS and shall be configured  as  described

 

         below:-

 

      a) For MMIPIS  portion  of  DDCMIS  including peripherals

 

         like CRT’s. printers, disks  etc.and other systems such 

 

         as  SWAS,  panel  instruments, requiring stabilized AC 

 

         power,  the  bidder  shall  furnish a  redundant UPS

 

         system.

 

      b) The  power supply to each DDCMIS system cabinets is  fed

 

         through dual 240 V AC Feeder from UPS.

     

7.03.00  The UPS system in the above   mentioned  configurations 

 

         employed  float cum boost chargers, battery banks, static

 

         inverters, static switches.  AC/DC distribution boards etc.

 

         shall meet the following specification requirements as a

 

         minimum.

 

 

7.04.00  Uninterruptible Power Supply(UPS) System

 

         The  UPS  system shall have  2×100%  parallel  redundant

 

         chargers and inverters, 2×100% battery bank, bypass line

 

         transformers  and  voltage  stabilizer,  static  switch,

 

         manual  bypass switch, AC/DC distribution boards,  other

 

         necessary protective  devices and accessories and  shall

 

         meet the following requirements as a minimum.

 

     (1) The  KVA rating of UPS shall be as required by  expected

 

         loads  and include 10% spare capacity guaranteed  at  50

 

         Deg.C  Amb.   However, for bidding  purpose,  a  minimum

 

         capacity  of  125 KVA shall be considered.   If  UPS  KVA

 

         rating is applicable at a lower ambient temperature than

 

         specified 50 Deg.C, the bidder shall consider  Derating

 

         factor  of  at least  1.5%  Deg.C  for  arriving  at  the 

 

         specified  UPS  capacity at 50 Deg.C ambient.   The  UPS

 

         shall have an over load capacity of 125% rated  capacity

 

         for 10 minutes and 150% rated capacity for 10 secs.  The

 

         inverter shall have  sufficient I2t capability to  clear

 

         fault in the maximum  rated branch circuit.  The  sizing

 

         of UPS shall be  based on the  power factor of the loads

 

         being fed subject to a maximum of 0.8.

 

     (2) Each  of the redundant chargers & batteries  shall  meet

 

         the  specification  requirements as per  clause  7.05.00

 

         above.

 

     (3) The UPS system shall be capable of operating without  DC

 

         battery in circuit under all conditions of load and  the 

 

         performance of various components of UPS like  inverter,

 

         charger  static switch etc. shall be guaranteed  without

 

         the battery in circuit.

 

     (4) The  UPS  system  design shall ensure that  in  case  of

 

         failure  of  mains  input power supply  to  one  of  the 

 

         chargers,  the  other charger whose  mains  input  power

 

         supply  is  healthy,  shall  feed to  one  or  both  the

 

         inverters  as  the  case may be  as  per  manufacturer’s

 

         standard practice & continue to charge the DC battery at

 

         all  load conditions.  The bidder should note that  this

 

         situation should not in any way load to the discharge of

 

         the DC battery.

 

     (5) Static Inverters

 

     (i) The  static  inverter shall be solid  state  type  using

 

         proven   pulse   width  modulation(PWM)   quasi   square

 

         wave/step wave technique.  The inverter equipment  shall

 

         include  all necessary circuitry and devices to  conform

 

         to   requirements  like  voltage   regulation,   current

 

         limiting,  wave shaping, transient  recovery,  automatic 

 

         synchronization etc. The steady state voltage regulation

 

         shall  be  +/- 1% and  transient  voltage  regulation(on

 

         application/ removal of 100% load)shall be +/-2%.   Time

 

         to  recover from transient to normal voltage  shall  not

 

         be   more  than 50 m sec. Frequency regulation  for  all

 

         conditions  of  input supplies,  loads  and  temperature 

 

         occurring  simultaneously or in any combination shall  be 

 

         better than +/-0.5%(automatically controlled). The total

 

         harmonic content shall be 5% maximum and content of  any

 

         single  harmonic  shall  be 2.5 %  maximum.  The  inverter

 

         efficiency shall be at least 85% on full load and 80%  on

 

         50% load.  The synchronization limit for maintenance  of

 

         synchronization  between  the inverter and stand  by  AC

 

         source shall be  48-52 Hz, field adjustable in steps  of

 

         0.5 Hz. DC input window of each inverter shall be  either       

         315 – 434 or 320-450 V DC.

 

    (ii) Over load, short circuit and load loss

 

         The  inverter shall be provided with suitable HRC  fuses

 

         at  the  input  and  output  which  will  permit  proper

 

         coordination  with other protective devices and  at  the 

 

         same  time  protect the inverter against damage  due  to

 

         internal  faults.   However,  if  the   Bidder’s  system

 

         design  does  not use fuses then the fuse  free  circuit

 

         breaker  may  also be permitted provided  it  meets  the

 

         specification  requirements.   All  necessary  equipment

 

         shall  be provided to protect the inverter against  over

 

         load, short circuit and 100% loss of load.  The inverter

 

         shall  be  self protecting against damage  if  energized

 

         with full load connected.

 

    (iii)Inverter   equipment  shall  include  all  solid   state

 

         circuitry and devices including stable oscillator etc. to

 

         enable  inverters to operate satisfactorily in  parallel

 

         sharing  mode  each  inverter taking   50%  load  during

 

         normal   operation.   In  case  of  failure  of   either

 

         inverter,  100% load shall automatically be  transferred

 

         to healthy inverter without any break and degradation in

 

         the  quality of UPS output and disconnecting the  faulty

 

         inverter automatically.

 

     (iv)The  inverter failure shall be alarmed and the   healthy

 

         inverter shall get synchronizing signal from the standby

 

         AC  source  and  remain  synchronized  within   the  set

 

         limits.   The  limits for  the  synchronization  between

 

         healthy  inverter and standby AC source shall  be  field

 

         adjustable.

 

     (v) On  failure  of  both  inverters,  the  loads  shall  be

 

         transferred  to  standby  AC power without  a  break  if

 

         within synchronization limits.  Provision of synchronous

 

         transfer with a break in case of inverter being out of  

 

         synchronization limits shall also be there with  standby

 

         source.

 

(6)       Static Switch and Manual Bypass Switch

 

 

         The  static  switch  shall be provided  to  perform  the

 

         function of transferring UPS loads automatically without

 

         any break from (i) faulty inverter to standby AC  source

 

         in  case of failure of both the inverters  and  (ii)from

 

         faulty inverter to standby AC source in case of  failure

 

         of both the inverters.

 

         Manual bypass switch shall be employed for isolating the

 

         UPS during maintenance.

 

(7)       Step Down Transformer and Voltage Stabilizer

 

 

         The  transformer shall be of low impedance type and  the 

 

         rating shall be such that extremely fast fault clearance

 

         is achieved, even in the largest rated branch circuit.

         The winding shall be electrolyte grade copper with F class   

         insulation with temp rise limited to class B .

 

         The  over load capacity of the  transformer/  stabilizer

 

         shall not be  less than 300% for 200 ms.  The stabilizer

 

         shall  employ  silicon  solid state  circuitry  and  the

 

         output   voltage  regulation  shall  be  +/-  2%.    The

 

         efficiency of the stabilizer shall be 95% or better.

 

 

7.05.00 (1) Float cum boost chargers:

 

 

         Bidder shall provide 2×100% redundant chargers. The charge 

 

         Shall  sized  to  meet the 100% load  requirements  of  the

 

         control  system  plus  recharge  the  fully   discharged

 

         battery within 8 hours.

 

         The  chargers  shall be  self  regulating,  solid  state

 

         silicon  controlled, full-wave rectifier  type  designed

 

         for single and parallel operation with battery and shall

 

         have  automatic voltage regulators for a  close  voltage

 

         stability  even  when  AC supply  voltage  and  DC  load

 

         fluctuates,  effective  current  limiting  features  and

 

         filters on both input and output to minimize harmonics.

 

         The  charger output regulation shall be  +/- 1% from  no

 

         load  to full load with an input power supply  variation

 

         of   +/-  10% in voltage and +/- 5%  in  frequency.   In

 

         addition  to  alarms on charger  panel,  potential  free

 

         contacts  for alarms like charger O/P voltage high  etc.

 

         shall  also  be  provided for use  in  DDCMIS.   Further

 

         isolated 4-20 mA signals shall be provided for important

 

         parameters like charger voltage etc.

 

     (2) Batteries

 

 

         The batteries shall be heavy duty Lead Acid PLANTE  type

 

         and shall be sized for one hours of full load operation. 

 

         The   PLANTE  Lead  Acid  batteries  shall  conform   to

 

         IS:1652.  For all sizing calculation, an aging factor of

 

         0.8  and a temperature correction factor of  0.935(based

 

         on temperature characteristics curve to be submitted  by

 

         the  contractor  and  at  a  temperature  of  1  Deg.C).

 

         Capacity factor and end cell voltage 1.85 V after one

 

         hour  shall be taken into consideration, if applicable

 

         and ambient  temperature shall be considered as the

 

         electrolytic temperature.  The  battery  sizing

 

         calculations shall be as per IEEE-485.

 

7.06.00  AUXILIARY EQUIPMENTS

 

 

         All required auxiliary equipment/materials as  finalised

 

         during  detailed  engineering shall be   furnished  with

 

         each charger/inverter/ battery bank and shall include as

 

         a  minimum  various meters(AC/DC voltage  /current,  KVA

 

         power  factor, frequency meters etc., circuit  breakers,

 

         selector  switches,  push  buttons  indicating   lights,

 

         ground  detector system, battery accessories  like inter

 

         cell  connectors, inter step connectors,  battery  racks

 

         etc.)further,  isolated  4-20 mA signals  for  important

 

         parameters  and  potential free contacts  for  important

 

         alarms shall be provided  for use in DDCMIS.

 

7.07.00  Bidder  shall  furnish  the  power  supply  distribution

 

         scheme,  single line diagram, all calculations  such  as

 

         charger/inverter  rating  calculations,  battery  sizing

 

         calculation   etc.,  during  detailed  engineering   for

 

         MPPGCL’s review and approval.  

 

7.08.00  The winding of transformer shall be electrolyte grade copper

 

         with F class insulation with temp rise limited to class B.

 

7.09.00  Bidder  shall  provide following minimum accessories per Battery set for maintenance   of  battery  and  safety   equipment for maintenance personals.

 

         a)  Hydrometer                           -   5 Nos. 

         b)  Thermometer                          -   5 Nos.    

         c)  Cell Tester(Voltmeter)               -   5 Nos.     

d)       Alkali Mixing Jar                    -   5 Nos.    

e)       Rubber Apron                         -   5  Nos.    

f)       Rubber Gloves                        -   5 Pair    

g)       Set of Spanners                      -   5 Pair    

h)       Spare acid in Container              -  25% of Total acid    

i)       Other accessories as per

Recommendation of Battery manufacturer

 

    j)  Specific gravity correction chart    -   2 Nos.

 

 

 

7.10.01       U P S (Factory Acceptance Test)

  

      a) Power Efficiency (IEC 146-2, IEC 146)at 100%load,50%load

      b) Load Test(Approved  Procedure)- Load regulation Test

      c) Audible Noise Test (IEC 146-2)

      d) Fuse Clearing Capability (Approved Procedure)

      e) Relative Harmonic content (IEC-146.2)

      f) Synchronous transfer and Synchronization Test (IEC 146-4)

      g) Temp. rise test without redundant fans(IEC-146.2)

      h) Input voltage  Variation Test (Approved Procedure)

      i) Over load test on inverter & charger(Approved Procedure)

      j) Insulation Test  (IEC 146)

      k) Restart Test (IEC 146-2)

      l) Short Circuit current capability (IEC 146-4- Clause 5.10)

      m) Output voltage & frequency tolerance (IEC 146-2)

      n) Voltage Current Division (IEC 146-2)

      o) Relative Harmonic content (IEC 146-2)

      p) Parallel Redundancy Test (* Simulation of parallel redundant

         fault (IEC-146.4)

      q) Over load Test (Final acceptance Test)

      r) Any other required as per  National/International standard

         or QAP.

 

7.10.02  Battery Charger

 

      a) Short Circuit current capability (IEC 146-2)

      b) Temp. rise test without redundant fans(Approved Procedure)

      c) S W C Test (Approved Procedure)

      d) Efficiency / PF (IEC 146-2, IEC 146)

      e) Audible Noise Test (IEC 146-2)

      f) Fuse Clearing Capability (Approved Procedure)

      g) Relative Harmonic content (Approved Procedure)

      h) Temp. rise test without redundant fans(IEC 146-2)

      i) Over load test on charger (Approved Procedure)

      j) Restart Test (IEC 146-2)

      k) Output voltage tolerance (Approved Procedure)

      l) Output  Voltage  Harmonic content (Approved Procedure)

 

       The above test Clause No.7.10.01 & 7.10.02 shall be  witness

 

       By owner / owner’s representative.

 

7.10.03 Testing at site

 

       Full load test shall be demonstrated after commissioning of  

 

       UPS and charger with batteries at site for 72 Hrs.

 

          7.10.04 Type  Test 

 

         Bidder shall submit  following Type Test Report along with

  

         final acceptance report.

 

a)    Battery as per  IS – 1652

 

b)    UPS/ Charger

 

i) IP degree

 

ii)Surge with stand capability (SWC)

iii)Dry heat Test (IEC – 68.2.2)

 

iv) Dump heat Test(IEC – 68.2.3)

 

 v) Vibration Test (IEC- 68.2.8)

 

vi) EMC Test (IEC- 61000.4.2)

 

 

The above all Type Test shall be conducted at National/

 

International Laboratories only.

 

7.11.05          Bidder shall submit following documents along with factory

 

          acceptance test (FAT) Report –

 

a)    Internal  Test Report along with heat run test report.

 

b)    Calibration certificate of  measuring instruments.

 

 

 

7.11.06          The contractor shall submit all above test results for

       

          Review and approval.