7.8.5 ELECTRICAL SUBSTATIONS

7.8.5.1 Transformer rooms

Transformer rooms are isolated from the other electrical installations by partitioning walls so that the possibility of a fire can be reduced substantially and its spread can be confined to the bare minimum. Cable fire sealing and fire resistant coatings will be provided for all H.T / L.T. and control cables, installed in transformer rooms, D.G. rooms, battery rooms and the switchgear rooms.

7.8.5.2 D.G. rooms

The D.G. rooms are partitioned and isolated from each other and from other electrical installations for prevention & propagation of fires in the room.

Day tanks for storage of diesel fuel are provided away from the D.G. sets in line with recommendations of the Petroleum Act 1934.

7.8.5.3 Common Provisions

Since the ordinary cable joint are easily unwirable and leads to frequent troubles, thermosetting type    joints are only used in H.T. cables.

Trenches in which cable trays are laid are walk through type facilitating quick and efficient servicing of cables. Motor driven pumps are provided for removal of water form the water pits, if flooding of trenches occurs any time.

7.9  FAILURE ANALYSIS FOR POWER SUPPLY SYSTEM

7.9.1 CABLING SYSTEM

Due to precautionary design measures such as Fire barriers and fire stops and water sealing for all outdoor to indoor cable pipe inserts, cabling system will be subjected to minimum damage from fire hazard. Power, control and instrumentation cables will be laid in separate trays and distinct route for different class of supply cables will be followed to the extent possible.

7.9.2 LIGHTING SYSTEM

7.9.2.1  FAILURE OF CLASS IV SUPPLY

In the event of complete failure of class IV supply, emergency lighting (which will  be 30% of the total lighting) fed from class III supply will be operational subject to momentary interruption due to time taken by DG sets to start (about 30 sec.). Critical lighting fed from class-II supply will remain available.

7.9.2.2  FAILURE OF CLASS IV AND CLASS III SUPPLY

In the case of failure of class-IV and class-III supply, Lighting fitting fed from class-II supply will be available for safety exit and critical lighting.

7.9.2.3 FAILURE DUE TO SHORT CIRCUITS AND EARTH LEAKAGE

The lighting feeder/ sub circuits will be protected against short circuits by corresponding MCB and Fuse switch. Earth leakage circuit breakers will be provided to protect the personnel from shock hazards due to earth leakage. 

7.9.3  PROCESS OFF-GAS (P.O.G) SYSTEM

There are two nos. of motor control centre (MCC) panels i.e. MCC (group-A) and MCC (group-B), one each for running and standby POG blowers. These two MCCs are physically separate from each other. The incoming cable routings to these two MCCs are physically segregated.

Case-I   Power interruption or maul-functioning in MCC (group-A).

The POG blowers in this case shall be fed from MCC (group-B). The standby motors on MCC (group-B) can be safely started and the corresponding POG blowers would run.

Case-II  Protection against fire.

In case of fire in MCC (group-A), the standby motors on MCC (group-B) can be safely started and the corresponding POG blowers would run. The fire will not affect MCC (group-B) because this panel is physically separate from MCC (group-A). 

7.10 POWER SYSTEM INTERLOCKS FOR AUTO MAINS FAILURE (AMF)/ AUTO  

       CHANGE OVER

7.10.1 CLASS-IV SWITCHGEARS (33KV, 415V)

All the switchgears have been provided with suitable metering devices for monitoring status and performances thereof. Some other devices have been provided to protect the switchgear under abnormal conditions.

For 33 KV switchgear the incoming breakers and bus section breakers are interlocked in such a way that it will not be possible to close any incomer breaker and bus section breaker simultaneously. This is to avoid parallel operation of the incoming breakers. Under normal operating conditions the bus section breaker will be kept open and the power supply from each incoming feeder will be confined to respective bus section. In the event of failure/ outage of any incomer feeder, the entire load will be automatically transferred to the healthy section by closure of the bus section breaker contacts.

7.10.2 CLASS-III SWITCHGEAR (415 V)

DG set breakers and bus section breakers will be kept open and power supply from each incomer will be confined to the respective bus section. Provision exists for the selection of auto/ manual mode of starting the DG set.

7.10.3 AUTO SEQUENTIAL SWITCHING / EMERGENCY TRANSFER (EMTR) SCHEME FOR CLASS-III LOADS

During outages of class-IV power supply on the incoming breaker of Class III switchgear, the  corresponding DG set gets started automatically. The base loads on DG set are energized within 30 secs. at the instant of closure of DG breaker of Class III switch gear. The motor loads shall be started in a pre determined sequence by a PLC based EMTR panel. The following class-III motors shall be started in a pre determined sequence-

Sr. no.	System	Rating of  motor (kW)	No(s). of motors	Type of starting	Running motors	Standby motors	Time delay (in secs.) provided for starting of single motor	Instant of starting the motor
1.	E2 fan	90	5	VFD	3	2	5	0 sec.
2.	DOG1	11	2	VFD	1	1	5	15th.sec.
3.	DOG2	11	2	VFD	1	1	5	20th.sec.
4.	EOG	22.5	2	VFD	1	1	5	25th.sec.
5.	VOG	15	2	VFD	1	1	5	30th.sec.
6.	Negative Pressure System (NPS) Blower -for lab glove boxes	2.25	2	DOL	1	1	5	35th.sec.
7.	Blister Off-gas (BOG) Blower -for sampling block	3.75	2	DOL	1	1	5	40th.sec.
8.	Pump hot cell Blower (HCV)	1.5	2	DOL	1	1	5	45th.sec.
	Total no. of motors		21
	Spares		25%
	Grand Total no. of motors		27

7.11  ELECTRICAL EQUIPMENTS

  7.11.1 MOTORS :

Motors will be used for cranes, ventilation systems, utilities, process pumps, etc. Motors shall conform to IS - 325, 3682 and 12615. All motors shall be squirrel cage energy efficient induction motors having TEFC IP 55 enclosure with Class-F insulation and Class B temperature rise conforming to IS 325 and 12615. Technical particulars of Motors are listed in Table-XVII. Some of the major loads e.g. Supply fans, Exhaust fans and Compressor motors shall be fed from VVVF (Variable Voltage Variable Frequency) drives. The VVVF drives incorporate the features of energy efficiency and capacity control. Technical particulars of VVVF drive are listed in Table-XVIII. The typical technical specifications of motors shall be as follows :

(i) Motors shall be designed to deliver rated output at rated power factor, continuously with

a)      Terminal voltage variations from 415V by +/- 10%.

b)      Frequency difference from 50 Hz by +/-5 %.

c)      Any combination of a and b.

(ii) The temperature rise determined by resistance measuring method shall not be more than 70 ^oC restricted to class B temperature rise limit) over an ambient of 50 ^oC.

(iii) The class of insulation provided shall be class F with the enclosure type TEFC IP 55.

(iv) The tendered motors  shall  be  capable  of  starting and accelerating  the driven equipment  satisfactorily  up to 80% of the rated speed within 10 - 15 seconds at a minimum voltage of 80% of the rated voltage at the motor terminals. Any limitation in the loading pattern at this stage shall be clearly indicated in  the quotation. The motor shall be designed for full-voltage Direct-on-line starting under normal course of operation.

(v) Under cold condition at room  temperature, the motors shall  be capable of thr  successive starts coupled to its driven equipment with a time interval of one minute between each successive starting operation and a fourth start 30 minutes later. The  motor shall further be capable of three equally time-spaced starts per hour under normal service conditions and the motor shall withstand all stresses and give satisfactory performance.

(vi) Under hot condition, the motor shall be capable of  two starts coupled to its driven equipment in quick succession (the time interval  between each starting operation being less than one minute) and a  third start 20 minutes later. The motor shall further be capable of three equally time-spaced starts per hour under normal service conditions and the motor shall withstand all stresses and give satisfactory performance.

 

(vii) The  motors  shall be capable of  withstanding for 15 sec, without stalling or abrupt change in speed (under gradual  increase of torque) an excess torque of 60%  of their rated torque with the voltage and frequency being maintained at their rated values.

 (viii) The starting torque and the pullout torque of the motor at rated voltage shall be above about 250% of full-load torque.

(ix) Motors  shall  be capable of satisfactory operation  at full loads for 10 minutes without injurious heating at a motor terminal voltage of 80% of rated voltage.

(x) The safe stall time of the motor shall be above the acceleration time of the driven equipment. Accelerating time of the motor with rated load of driven equipment connected to it, shall  not  exceed  the corresponding  safe  stall time of the  motor even  if stalling occurs  when  motor  is  at  rated  operating temperature (i.e. under hot condition), at all applied voltages from 80% to 110% of rated voltage.

(xi) The motors shall be capable of withstanding without mechanical damage at least 120% of rated speed for 1 minute or as imposed by the driven equipment, whichever is higher.

(xii) Motors shall be provided with cooling fan, preferably made of ‘Cast Aluminium’.

(xiii) Terminal box shall be suitable for terminating aluminium conductor FRLS insulated   armoured cables of appropriate size.

(xiv) Motor windings shall be given power house treatment for protection against tropical weather conditions.

(xv) Motor vibration shall be limited as per IS 12065.

(xvi) The permissible noise level shall be limited as per IS 12075.

 (xvii) The motor efficiency and power factor shall be greater than 80% and 0.8 respectively.

(xviii) Motors shall have anti-friction (ball roller or spherical roller type) bearings in cartridge housings.

(xix) Routine and type test as per IS-325 and IS-4029 shall be carried out. Additionally, the following tests shall also be carried out.

a) Full load test to ascertain temperature rise at 90% or 110% of rated voltage.

b) Enclosure protection test.

c) Noise & vibration measurement test.

d) Over speed test.

e) Speed-torque characteristics.

f) Starting current Vs time characteristics, at 80% & 100% voltages.

g) Rotor temperature rise under locked-rotor condition.

h) Half-an-hour no-load run test for all the motors.

(xx) The motor winding as well as housing shall be given special epoxy-based anti-corrosive treatment for protection against chemically aggressive gases or fumes. The equipment shall  be thoroughly degreased & all rust, sharp edge and scales removed. 

(xxi) Motors of 25kW and above shall be provided with Positive Temperature Coefficient (PTC) thermisters for protection against high winding temperature.

(xxii) Motors of 25 kW and above shall be provided with space heaters.

(xxiii) Motors shall be rated for the load and duty cycle of the intended service.

(xxiv) Motors for certain applications viz. exhaust fans, off-gas blowers shall be compatible for use with VVVF drives.

7.11.2 ILLUMINATIONPlant’s lighting is envisaged with the energy efficient fluorescent lamps and/or compact FL lamps for general areas and High bay fittings in areas with high head room. 30% lighting on class-III power supply and exit lights with class-I DC power supply shall be provided. 110V DC bulkhead type exit lights will be provided on top of doors for evacuation under emergencies through all normal and emergency exits of the plant. Illumination levels for various areas, rooms have been chosen in line with IS recommendations/ BARC standards. The illumination levels for various areas of the plant are attached vide Table-XVIV.

 The salient features of lighting system are as follows:

-Separate distribution panel shall be provided for each floor.

-Lighting transformers shall be provided for high block as well as sub-station and low block.

-Separate MCB DBs shall be provided for lighting distribution of Class-IV, III, II & I loads.

-MCB distribution boards (DBs) shall be distributed in the plant areas from functional usage point 

 of view and from the point of view of building expansion joints.

-For lighting circuits, the load is restricted to a maximum of 1 KW and for plug circuits it is restricted to 3 KW. A diversity of 50% is considered on plug circuits for sizing MCB DBs.

-Separate circuits for lighting and plug points.

-Separate conduits for class-IV, class-III, class-II & class-I circuits.

-30% of the lights shall be provided with class-III power supply.

-Class-II UPS and class-III lights shall be provided in control room (50% each).

-DC bulkhead type exit lights shall be provided for emergency evacuation.

-Inverter based class-I DC lights for service corridors, access gallery areas for emergency evacuation purpose.

-High bay fittings shall be provided in areas with high head room.

-Provision of back-up fluorescent lighting for areas illuminated by high bay fixtures.

-Process cells to be equipped with ‘SON’ lights through shielding plugs (withdrawable type).

-Gold plated 230V plug receptacles shall be provided in cells for less maintenance.

-Separate neutral shall be provided in each circuit for isolation.

-10 KA SPN MCBs shall be provided for lighting and plug circuits.

-HFFR wires shall be used for building electrification. 1.5 sq.mm. Cu wires for lighting circuits  and 2.5 sq.mm. Cu wires for plug circuits. 

The following measures for energy conservation in illumination system shall be adopted-

-Use of compact fluorescent lamps (CFLs) in cabins and corridor areas.

-Use of low loss or electronic ballast.

-PID control for 50% normal lights in sampling gallery and isolating corridor.

-Access/ Sampling gallery ‘normal’ lighting fixtures controlled through occupancy based PID   sensors for energy conservation.

-LED lamps for ‘Aviation Obstruction Lighting Fixtures’.

7.12 COMMUNICATION SYSTEM/ NETWORK

The plant’s communication network is a vital safety related system. Apart from its usefulness in normal plant operations, it is indispensable during emergency situations. A dedicated PA system shall be provided for project ROP, AWTF and SFSF. Telephone exchange system shall be common for both PREFRE and ROP.

The communication system wiring shall be provided for the following sub-systems:

i) Public Telephone cum Intercom system: This system shall be provided for communication within and outside the plant complex. A dedicated 48V class-I battery bank has been used for  telephone system.

ii) Public address (PA) and emergency alarm system.

This system shall be provided for giving alarms / paging to the plant staff during normal and emergency condition. Class-II power supply is envisaged for public address system.

7.13 Electrical Control System

    Electrical control system of ROP covers “PLC control system” and “Electrical  SCADA system”. “PLC control

    system” provides remote controls, interlocks and  status monitoring of utility fans and blowers. PLC system also

    provides auto sequential starting of class-III equipments at a pre-defined time intervals. 

     An “Electrical SCADA system” is proposed for on-line monitoring, data logging  and remote control of electrical equipments/ devices.

7.13.1  PLC based control system

PLC based system is provided for remote control of ventilation fans, off-gas blowers and interlocking of  fans and blowers. The PLC panel also provides auto sequential starting of  class-III loads during mains power outage. PLC panel has been provided with redundant CPU, redundant power supply unit and redundant communication links. Control supply to panel has been provided from class-II UPS system.

7.13.2  Electrical SCADA system

                            An Electrical SCADA system is being provided to facilitate on-line monitoring  and remote control of various electrical equipments installed in the ROP plant from a PC based centralized control room. Various analog and digital signals from Transformers, DG sets, Breakers, VFDs (Variable Frequency Drives),                             UPS systems and Motors would be gathered on a PLC through PROFIBUS/MODBUS cables.  These devices have been provided with communication features. Provision also exists for data display in Main Control Room Panel (MCRP).  

7.13.3 Control roomsAll the important motors have been provided with remote control and annunciation facility. For all the motors local control is available in the MCCs. Some of the motors of auxiliary systems such as make-up area pumps, tank space pumps etc., have been provided with remote annunciation, though their controls will be only local at the MCCs. Local/remote selector switches for controlling the motors have been provided in the main/ utility control-room so that the `start' facility is restricted to two points only.

The control centre provided for the remote control and annunciation of motors is :

a) Main control room in the Low Block of main process building

b) Utility control room in high block building

7.13.4 Main control room

In this control room, there are 9 nos. of control panels housing the actuators, controllers, recorders, monitors, indicators, enunciators, measuring instruments and a seem graphic flow sheet.  The panels are dedicated and identified process wise.

The control and annunciation for the motors of the process pumps installed in access galleries have been provided in the respective process panel. A separate panel is dedicated to the electrical systems where alarm annunciation of electrical drives have been provided for electrical equipments. 

List of electrical and utility equipments being monitored/ controlled from main control room is listed vide Table-XVVII.

7.13.5 Control power supply

The instrument power distribution boards (IPDBs) provide control power supplies to the following equipments in the main control room.

24V DC power supply to transmitters, relays, indicating lamps.

48V DC power supply to solenoid valves (SVs).

230V AC power supply to instruments, recorders, annunciators, controllers, computers, data acquisition system, CCTVs, fire alarm system etc.

The IPDBs to be located in the emergency control room, shall be fed with class-II UPS power. 

Critical instruments and health physics area monitors have been provided with class-II uninterrupted power supply.

7.13.6 Annunciation Scheme

The alarm annunciator indicates the status of the drive and gives alarm when the status changes, on operation of start/ stop push button or on fault.  The alarm annunciation used is of two types. a) Integrated architecture type b) split architecture type. They operate on 230 V AC power supply.  One potential from NO/NC contact from the drive's control circuit  (either from auxiliary relay or main contactor) is terminated on the anunciator’s signal terminal for sensing the status of the drive.  Terminals are provided in the annunciator to connect the same to common hooter for alarm. The annunciators are provided in 3x3x2, 4x3x2, and 4x4x2 configuration. The first two are of integral architecture and the last of split architecture type.

The anunciator logic followed is as under:

S.No.      Sequence                     Audio alarm      Visual indication

----------------------------------------------------------------------------------

1.           Normal condition                 No             Yes (ON window)

              (Motor running)

2.           Change of status                  Yes             No (ON window)

              (Motor tripped/stopped)                         Yes (OFF window)

3.           Acknowledgement               No             No (ON window)

                                                                             Yes (OFF window)

4.           Normal                                No              Yes (ON window)

              (Motor started)                                       No (OFF window)

 --------------------------------------------------------------------------------

7.14  ELECTRICAL SYSTEM INTERLOCKS

7.14.1 Power Systems

i) Safety interlocks and protection are provided for transformers, DG sets, batteries, rectifiers, motors etc. as per standard practices and IEEE recommendations.

ii) Earth leakage circuit breakers are provided as per Indian Electricity Act.

iii) Earth fault annunciation will be introduced for class-I DC batteries.

iv) Provision for manual initialization/ activation of instrument/control supplies in control room  shall  be made.

7.14.2 Process Pumps

Access Gallery Pumps

Provision for 3A and 2A cycle interlocks shall be made at site.

Process Pumps Tank Space - (Acid Recovery System/Formaldehyde Pumps)

Provision for high pressure/temperature/level cut-off has been made in Motor control centres.

7.14.3 Interlocking Scheme For Supply Fans, Exhaust Fans & Off Gas Blowers.There are 5 nos. of supply fan motors e.g. V2F1, V2F2, V2F3, V2F4, V2F5. Each motor is of rating 3-phase, 415V, 75 KW. Fan nos. V2F1, V2F3, V2F5 are fed from MCC(V1/V2)-GroupA and fan nos. V2F2, V2F4 are fed from MCC(V1/V2)-GroupB. All V2 fan motors are provided with Variable frequency drives (VFDs).

1.       There are 5 nos. of exhaust fan motors e.g. E2F1, E2F2, E2F3, E2F4, E2F5. Each motor is of rating 3-phase, 415V, 90 KW. Fan nos. E2F1, E2F3, E2F5 are fed from MCC(E2)-GroupA and fan nos. E2F2, E2F4 are fed from MCC(E2)-GroupB. All E2 fan motors are provided with Variable frequency drives (VFDs).

2.       The interlock between V2 and E2 fan motors shall be provided such that

                    Not more than any three nos. V2 fans shall run at a time.

                    Not more than any three nos. E2 fans shall run at a time.

                     If any running E2 fan trips, corresponding one running V2 fan shall be tripped. Subsequently, one

                    standby E2 fan will come on-line automatically in the event of failure of running E2 fan and one

                    standby V2 fan shall be switched ON manually.

             

                    Once class-IV power supply to above mentioned MCC panels goes off and class-III DG power

                     supply is  restored to these MCC panels, pre-configured one no. E2 fan shall start automatically.

                    In case of fire, all V2 fans are to be switched off automatically and E2 fans shall remain ON.

3.       DOG-1A, DOG-1B, EOG-1, VOG-1, ‘Negative pressure system-1 (NPS-1)’, ‘Blister blower-1 (BB-1)’ & ‘HCV blower-1 (HCVS-1)’ motors are fed from MCC(POG)-GroupA. Likewise, DOG-2A, DOG-2B, EOG-2, VOG-2, ‘Negative pressure system-2 (NPS-2)’, ‘Blister blower-2 (BB-2)’ & ‘HCV blower-2 (HCVS-2)’ motors are fed from MCC(POG)-GroupB. All DOG, EOG & VOG blower motors are provided with Variable Frequency Drives (VFDs). All NPS, BB & HCVS blower motors are provided with DOL starters.

             The interlock between E2 fans and above blower motors shall be provided such that If no E2 fans are

              running, all Negative pressure system blower motors (NPS-1 & 2 both), all ‘Blister Blower’ motors

             (BB-1 & 2, both) and all HCV blower motors (HCVS-1 & 2, both) shall be tripped.

6.      Interlocks between Off-gas blower motors shall be provided such that,

6.1    Out of 2 nos. of blowers i.e. DOG-1A and DOG-1B, only 1 no. of blower shall run at a time.

6.2    Out of 2 nos. of blowers i.e. DOG-2A and DOG-2B, only 1 no. of blower shall run at a time

6.3    Out of EOG-1 & EOG-2, only 1 no. blower shall run at a time.

6.4    Out of VOG-1 & VOG-2, only 1 no. blower shall run at a time.

6.5    Out of ‘NPS-1 & 2, only one no. blower shall run at a time.

6.6    Out of ‘BB-1 & 2’, only one no. blower shall run at a time

6.7    Out of ‘HCVS-1 & 2 blowers’, only one no. blower shall run at a time.

6.8   In case of failure/ stop of DOG-1A, DOG-1B shall start automatically and vice-versa.  

6.9   In case of failure/ stop of DOG-2A, DOG-2B shall start automatically and vice-versa

6.10 In case of failure/ stop of EOG-1, EOG-2 shall start automatically and vice-versa.  

      6.11  In case of failure/ stop of VOG-1, VOG-2 shall start automatically and vice-versa.

      6.12  In case of failure/ stop of  ‘NPS-1’, ‘NPS-2’ shall start automatically and vice versa.

      6.13  In case of failure/ stop of ‘BB-1’, ‘BB-2’ shall start automatically and vice versa.

      6.14  In case of failure/ stop of ‘HCVS -1’, ‘HCV S-2’ shall start automatically and vice versa.

7. In case any Off-Gas Blower (as mentioned in sr. no.4 above) starts, corresponding one no. Digital Output (D.O.) signal shall be generated by the PLC immediately for opening the suction valve and  another Digital Output (D.O.) shall be generated after a pre-set time delay for opening the discharge  valve.

7.14.6 AHUs

Lab AHU motors shall be interlocked with the exhaust fan motors (1R + 1S) of lab exhaust system in such a way that all AHU stop when the running exhaust fan stops.

7.14.8 Underground Water Sump

Provision for cut off of U/G water pump motors is made for water level high in O/H tank through a level switch. Provision for auto start of motor also exists on fall of water level in O/H tank (a separate level switch to be provided in O/H tank for the purpose).

7.14.9 Laboratories

Lab calciners are interlocked for high temperature trips.

Compressors/Chilled Water Compressors/Boilers

Safety interlocks are provided with these system installations at site.

8.0 ACTION FOR COMPLIANCE DURING CONSTRUCTION/ OPERATION :

8.1 ACTION FOR COMPLIANCE DURING CONSTRUCTION :

8.1.1        A gap of 5 metres should be maintained from 33 kV power line during construction. There should  

               be full electrical barrier. Vertical barriers should be installed with GI sheets during construction  of  

               new sub-station.

8.1.2        The MCC/ PCC panel shall be kept away from the corrosive atmosphere in order to prevent corrosion.

8.2 ACTION FOR COMPLIANCE DURING OPERATION :

8.2.1     Any one 33 KV feeder is capable of meeting  entire load requirement of plant for normal

             operation. Any  1 (one) out of the 2 (two) HT feeders shall be  available for plant operation.

8.2.2        Loading of HT incomers from ROP sub-station shall be restricted to 300 Amps (maximum).

8.2.3        H.V. circuit breaker earthing trucks shall be used for the earthing purpose during shut down jobs.

8.2.4        If  all  the two feeders fail, normal  power  supply will  not  be  available in the plant.  DG-  sets  will provide emergency power supply under such circumstances.

8.2.5        During the healthy condition, three  phase  AC voltage  at MV switchgears shall be maintained between 415 to 433V by keeping the off-load tap changer set at normal tap position. However, if the grid is unhealthy for long period, the off-load tap changer   shall  be set  at suitable position to maintain the  transformer  secondary  voltage  on  load, within 415V ± 5%,  depending upon the grid conditions.

8.2.6        Transformer  winding  temperature shall not  exceed  a limit of 155 °C. (as per  winding resistance indicator) under normal conditions.

8.2.7        Load  currents,  voltage, power in KW,  power  factor, power consumption in KWH,

frequency shall be monitored in every shift on all the H.T./ L.T. switchgears.

8.2.8        In case of failure/outage of 110V DC control supply in ROP substation, a visual indication and audio alarm shall be annunciated and the control supply shall be made available  for the breaker controls  within  one hour. "Trip circuit healthy" indication shall be monitored continuously.

8.2.9        At-least one DG set shall be  available  for  plant-operation. If any DG Set fails/develops a fault/problem, it shall be made available for operation within 7 days.

8.2.10    The diesel generator sets shall be started and run on  no-load or under partial-load for 30 minutes every week, under manual  mode of controls. The D.G. set shall be tested on load once in  a month under manual mode of  control.

8.2.11    Automatic actuation of the diesel generators shall be ascertained by simulating failure of  normal  power supply  and the gen-sets shall be load tested  for  one hour at least once every month.

8.2.12    For evaluating the performance of the DG set and to establish stabilized engine parameters, the DG set shall be tested to its full load using water load bank(s).  This will ensure that steady state engine parameters like temperatures are within design limits and also ensure rated capacity of DG set.

8.2.13    In order to ensure healthiness of engine safety trips for DG sets, yearly calibration of engine mounted sensors like cooling water temperature, lube oil pressure, lube oil temperature etc. shall be carried out.The fuel oil level in the day tanks and air pressure in compressed air cylinders shall be checked everyday to ensure full stock.  Similarly, air pressure in compressed air cylinders;  cooling  water temperature/ level  and  lube oil pressure shall  also  be  checked every hour during D.G. operation for ensuring  trouble free operation of D.G. sets.               

8.2.14    In case of failure of ‘PLC based auto sequential starting system’, the same shall be made available within 7-days. Exhaust and off-gas fans shall have to be connected to the class-III power supply one by one in a preset sequence with an interval of about 1 minute between two subsequent motor-starters.

8.2.15    If any circuit breaker/switch fuse unit of class-III switchgear    develops   a   fault   it    shall    be repaired/replaced with an identical spare unit within 24 hours. Power supply to the concerned emergency load centres shall be restored within 1 hour with the help of  duplicate  emergency feeder of  provided  for  the purpose.

8.2.16    If UPS-A of the two UPS sets (i.e. UPS-A & UPS-B) becomes inoperable, UPS-B shall feed the loads of UPS-A. If UPS-B out of two UPS sets becomes inoperable, the class-III bypass line of UPS-B shall feed the loads of UPS-B. The inoperable UPS shall be made operable within 7 days. On the simultaneous failure of incoming power supply to both UPS, both UPS will work on their respective battery for 1 hour and plant shall be shut down in the planned manner.

8.2.17    To assess capacity of batteries in the UPS system, capacity test on battery bank shall be carried out annually.

8.2.18    The  electrolyte  level, specific  gravity  (1.2)  and voltage  of pilot cells (2.2 volts) shall be measured in every shift i.e. thrice a day and for all the cells once  a week.  Batteries shall be load tested once in two years.  Healthiness of D.C. supply and its indications on all the switchgears shall be checked every day.                                         

8.2.19    One ACVR constitutes ‘Float cum Boost’ and ‘Float charger’. During boost charging of a ‘discharged’ battery set, the battery set shall be charged by the corresponding  ‘Float cum  Boost charger’ and the other Float charger shall feed to the D.C. loads. Main bus-coupler  shall remain open.

8.2.20    DC exit lights connected to class-I power supply system shall be tested once in three months. Record for the same shall be maintained.

8.2.21    Battery discharge load test shall be conducted for at least 10 hours.

8.2.22    Proper administrative control and approved procedure shall be followed during crane operation, with class-III power supply, to prevent breakdown.

8.2.23    Performance reliability of protection relays, including settings shall be carried out yearly.

8.2.24    Insulation rubber mats shall be installed before all the electrical panels.

8.2.25    Measurement of earth resistance shall be carried out quarterly in a year.

8.2.26    Checking electrical healthiness of portable tool shall be carried out as & when tools are issued. Records for the same shall be maintained.

8.2.27    Master PM schedule shall be prepared for the entire facility. Maintenance history cards for all the equipments shall be prepared.