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Kochi Refinery PRESENTATION ON SHUT DOWN IN BPCL- KOCHI REFINERY RAHUL . R . NAIR Trainee-BPCL-KR

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PRESENTATION ON SHUT DOWN IN BPCL- KOCHI REFINERY

PRESENTATION ON SHUT DOWN IN BPCL- KOCHI REFINERY

RAHUL . R . NAIR Trainee-BPCL-KR

Kochi Refinery11 kV & 3.3 kV SWITCH GEAR

Kochi Refinery1. There are many substations present in the plant area and also the amount of Switch Gears and other electrical distribution are in large numbers.2. Let us consider a 11kV and 3.3kV present in DHDS substation and its electrical distribution system. 3. The panels are HT-2007 ( 11kV SWGR ) and HT-2008 ( 3.3kV SWGR ). 4. The supply to the 11kV SWGR is fed from Captive Power Plant ( CPP ) through transformer and supply to 3.3kV SWGR is fed from 11kV SWGR through a step down transformer rated 11kV / 3.3kV.5. The step-down transformers are present in the substation yard.

Kochi Refinery9. The 11kV and 3.3kV SWGR consists of two incomers ( 1 & 2 ) and a Bus Coupler .10. The 11kV SWGR consists of transformer feeders and 3.3kV SWGR consists of HT motor feeders.11. These switch gears consists of mainly SF6 Circuit Breakers ( Sulphur Hexa-Fluride ) of 1250 A .

Kochi Refinery

The panel consists of the following components :-

1. POWER SWITCHING DEVICESa) SF6 Circuit Breakersb) SFU ( Switch Fuse Unit ) with contactor modulec) High Rupturing Capacity Fuse ( HRC )d) Contactors

2. CONTROL DEVICESa) Trip Selectionb) TNC Switchc) Ammeter Switchd) Test Terminal Blocke) Synchronizing Selector Switch

PANEL DETAILS

Kochi Refinery

3. INDICATIONSa) Breaker On / Offb) Auto Tripc) Spring Chargedd) Ready to Closee) Test / Servicef) Gas PR Low

4. METERINGa) Voltmeterb) Ammeterc) Watt Hour Meter d) Power Factor Meter

Kochi Refinery5. PROTECTION ( RELAYS )a) Motor Protection b) Sensitive Earth Faultc) Over Current d) Under Voltagee) Check Synchronousf) Master Tripg) Inverse Definite Minimum Time O/C & E/F Protectionh) Line Potential Transformeri) Bus Potential Transformer

6. AUXILIARY RELAYS7. COMBIFLEX RELAYS

Kochi Refinery8. INTERLOCKSa) Door Interlocksb) Mechanical Interlocks

9. BUS DUCT / BUS CHAMBER

10. BREAKER SLIDING CONTACTSa) Control Cablesb) Inter-panel Wiring11. CABLESa) Motor Cables ( 3-core )b) Feeders ( 3.5-core )c) XLPEd) PVC

Kochi Refinery12. AUTO CHANGE-OVER SCHEME

13. CONTROL SUPPLY

14. SINGLE LINE DIAGRAM

Kochi RefineryPOWER SWITCHING DEVICES

Kochi RefinerySF6 CIRCUIT BREAKERS

SF6 circuit breakers may use compressed air (puff) or the magnetic force of the arc itself to elongate the arc. As the length of the sustainable arc is dependent on the available voltage, the elongated arc will eventually exhaust itself. Alternatively, the contacts are rapidly swung into a small sealed chamber. The escaping of the displaced air thus blowing out the arc.

Kochi Refinery

c)

The Isolator and Switch Fuse unit of Fuse Switch Unit are manually operated devices. A Switch Fuse Unit or a Fuse Switch Unit also functions like the Switch, but can interrupt the power supply by blowing the fuse in case the connected load draws excess current or when a short circuit occurs.SWITCH FUSE UNIT WITH CONTACTOR MODULE

Kochi RefineryCONTROL MODULE

Kochi Refinerya) In addition to providing a means to open and close the contacts manually, acircuit breaker must automatically open its contacts when an overcurrent is sensed. The trip unit is the part of the circuit breaker that determines when the contacts will open automatically. The trip unit includes a trip mechanism that is held in place by the trip bar. As long as the trip bar holds the trip mechanism, the mechanism remains firmly locked in place. Trip flags off when a fault occurs ( over load ,short circuit , under voltage etc).

TRIP

Kochi Refineryb)

TNC Switch is a three position Switch. The switch are of two types : i) Having lockable Trip position and other with ii) spring returnto normal Neutral position. For manual operation this switch is used to TRIP a breakerby moving it towards trip position and close by moving ittowards Close position.In neutral position all the operations on AUTO mode or from remote can be done, as per the scheme.For keeping the breaker in OFF condition or for isolation,the switch can be kept in lockable TRIP position, if thatfacility is available in the switch.

TNC SWITCH

Kochi RefineryINDICATIONS

Kochi Refinery

a) GREEN : Breaker Open & Mechanism charged RED : Breaker Closed AMBER : Trip/Trip Circuit Trouble WHITE : Trip Circuit Healthy ON / OFF INDICATIONS

Kochi Refinery

b) During auto trip the circuit breaker will not get ON without re-setting the fault or any other cause for the trip. Once the trip is reset , the circuit breaker can be put on to feed the load.c) Spring is charged by providing a DC-voltage for the spring charging motor .The control circuit requires DC voltage. This will charge the breakers within minutes . Thus the charged spring stores potential energy which is used to operate quick mechanisms( opening or closing of breaker contacts ).AUTO TRIP & SPRING CHARGING

Kochi Refineryd) This SPDT switch indicates that the circuit breaker is ready to close and that the following conditions exist:

The circuit breaker is open The stored energy mechanism is charged The control unit is reset The circuit breaker opening push button is neither locked nor padlocked The circuit breaker is in the fully connected or test position The switch is field-installable.READY TO CLOSE

Kochi Refinery

e) When the breaker is racked out completely for maintenance a test indication is signalled on PMCC. At this point of time the breaker does not have any contact with the bus bars. When the breaker is racked in completely a service indication is signalled on PMCC . This shows that the breaker is in service and ready to use.

TEST / SERVICE

Kochi RefineryGAS PRESSURE LOW

Kochi RefineryMETERING

Kochi Refinery

a) A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit. Digital voltmeters give a numerical display of voltage by use of an analog to digital converter.

VOLTMETER

Kochi Refinery

b) Anammeteris ameasuring instrumentused to measure theelectric currentin acircuit. Electric currents are measured inamperes(A), hence the name. Instruments used to measure smaller currents, in milli ampere or micro ampere range, are designated asmilli-ammetersormicro-ammeters.

AMMETER

Kochi Refinery

c) Watt hour meter is a device that measures and records over time theelectric powerflowing through a circuit. Although there are several different types of watt-hour meters, each consists essentially of a small electricmotorand a counter. A precise fraction of the current flowing in the circuit is diverted to operate the motor. The speed at which the motor turns is proportional to the current in the circuit, and, therefore, each revolution of the motors rotor corresponds to a given amount of current flowing through the circuit.

WATT-HOUR METER

Kochi RefineryPOWER FACTOR METER

A power factor meter is a kind of electrodynamometer, which is constructed with two coils that are movable. These coils are set at 90 degrees to one another. One can measure the power factor with the help of a power factor meter. The application of a power factor meter is numerous like start up analysis of a motor or even detection of hot spots.

Kochi RefineryPROTECTION

Kochi Refinery

a) Motor Protection Relays are useful for protection of 3-phase AC induction motors against various hazards. With their unique advantages they eliminate use of a thermal / bimetal relay for motor protection. Being current sensing, they are to be selected according to motor rating and are available for practically all ranges of motors. These relays are ideally suitable for Air-conditioning Compressor motor protection, as also for motors in machines, conveyors, cranes/hoists and lifts, and for pumps.

MOTOR PROTECTION RELAYS

Kochi Refinery

b) Sensitive Earth Fault Relay is a type of relay that is used to detect the presence of an earth fault during the operation of an electrical device. Earth Fault occurs when there is unbalancing of loads due to which the amount of current flowing through the three phases ( R,Y,B ) will be in a different ratio.

SENSITIVE EARTH FAULT RELAY

Kochi Refinery

c) An Over Current Relay is a type of protective relay which operates when the load current exceeds a preset value. TheANSIdevice number is 50 for an instantaneous over current (IOC), 51 for a time over current (TOC). In a typical application the overcurrent relay is connected to a current transformer and calibrated to operate at or above a specific current level. When the relay operates, one or more contacts will operate and energize to trip (open) acircuit breaker

OVER CURRENT RELAY

Kochi Refinery

d) A relay that has contacts that operate when the voltage drops below a set voltage is called Under Voltage Relays. Under voltage relays are used for protection against voltage drops, to detect short-circuit faults, etc.An undervoltage release triggers the breaker to open when the applied voltage falls below a threshold. Often, an undervoltage release is operated from the system and is intended to cause the breaker to open in the event something happens to cause the system voltage to collapse.

UNDER VOLTAGE RELAYS

Kochi Refinery

e) Check Synchronising Relay : When closing a circuit breaker between two energized parts of the power system, it is crucial to match voltages on both sides of the circuit breaker before closing. If this matching or "synchronizing" process is not done correctly, a power system disturbance will result and equipment can be damaged. In order to synchronize properly, three different aspects of the voltage across the circuit breaker must be closely monitored. The three aspects of the voltage are called the synchronizing variables and are:1. The voltage magnitudes2. The frequency of the voltages3. The phase angle difference between the voltages

CHECK SYNCHRONISING RELAY

Kochi RefineryMASTER TRIP RELAY

Master Trip relays or Lockout relays are bipolar devices designed to operate when voltage is applied. They are a link between protective relays and power circuit controlling devices such as circuit breakers. Their purpose is to multiply the outputs of protective relays or control relays so that one relay can trip and block closing of numerous power circuit controlling devices.

Kochi RefineryIDMTL O/C & E/F PROTECTION

IDMTL O/C & E/F PROTECTION is design to meet demand of low and medium switchgear control. This type of relay is a 3 OC and 1 EF relay with Instantaneous high set and programmable output to simplify feeder protection wiring. It continuously monitors all 3 phase and earth current, through CT connections. The high-speed micro-controller samples this current through a 12-bit A/D converter. The micro-controller performs powerful Digital Algorithms to find out Amplitude of current signal, and then this value is use for protection and metering function. All measurement is tuned to fundamental frequency. Each input current is also displayed on 16 x 2 LCDdisplay for metering. The Relay is having main three functions 1) Protection 2) Self-Supervision 3) Measurement

Kochi RefineryLINE POTENTIAL TRANSFORMER

Potential Transformer is designed for monitoring single-phase and three-phase power line voltages in power metering applications. A Potential Transformer is a special type of transformer that allows meters to take readings from electrical service connections with higher voltage (potential) than the meter is normally capable of handling without at potential transformer. Potential transformer models are available for metering AC voltages from 120 volts AC to 36,500 Volts AC with burden ratings up to 500 VA.

Kochi RefineryBUS POTENTIAL TRANSFORMER

It's a PT (potential transformer) that's attached to the bus. This depends on the burden rating of the PT. If it's a 15VA PT, made for a secondary voltage of 120V, then the maximum secondary current should not exceed 0.125A.Potential transformer is that which transforms one range of voltage (potential difference ) to another range without changing frequency. Potential transformers are used to (1) reduce the value of a high-voltage supply to a lower value (often 120 V) so that it may be read by ordinary voltmeters, and (2) to electrically-isolate the voltmeter from the high-voltage source for the purpose of safety.

Kochi RefineryAUXILIARY RELAY

Kochi Refinery

Auxiliary Relay is relay which will repeat the operations of protective relays such as tripping , time lag , breaking of trip circuit current , giving alarms , showing flags etc. Protective relays contacts are light in weight and hence cannot carry large amount of current for a long period. Therefore auxiliary relays, auxiliary switches and repeat contacts are used to assist protective relays.

AUXILIARY RELAY

Kochi RefineryBUS DUCT / BUS CHAMBER

Kochi Refinery

Abus ductismetal racewaythat supports and contains a group of electrical bus bars. The duct comes in standard 10 foot lengths.One of the greatest advantages ofbus ductsis that they are capable of adding or removing a branch circuit without removing voltage from the whole duct.

BUS DUCT / BUS CHAMBER

Kochi RefineryINTERLOCKING

Kochi Refinery

a) This lock prevents the compartment door from being opened when the circuit breaker is in the connected position. If the circuit breaker is put into the "connected" position with the door open, the door can be closed without disconnecting the circuit breaker. The figure typically shows a door interlock pattern.

DOOR INTERLOCK

Kochi Refinery

b) mechanical interlocks disconnecting when circuit breaker is closedDuring any disconnecting attempt when the circuit breaker is closed, an interlockingdevice ensures the tripping of the circuit breaker before the actual separation of themain disconnects. The circuit breaker remains, however, operable in the other positions: test, disconnected and withdrawn.

MECHANICAL INTERLOCKS

Kochi Refinery circuit breaker closing when not completely connectedThe interlocking device mentioned above prevents closing of the circuit breaker if theconnecting operation is not completely achieved. connecting circuit breaker when door openedVPEC and VPOC options prevent the compartment door from being opened whenthe circuit breaker is in the connected position and from connecting the circuitbreaker when the door is open.

Kochi RefineryBREAKER SLIDING CONTACTS

Kochi Refinery

a) Control Cables are a multistrand cable for transmission of information on the state, location, or operating conditions of objects being controlled. It is used where direct access to such objects is difficult or impossible. Control cables occupy an intermediate position between power cables and communications cables. They are widely used to connect electric instruments and apparatus, for secondary switching of remote-control starters and regulators, for protective relaying, and in automation.

CONTROL CABLES

Kochi Refinery

b) Inter Panel Wiring is used for control equipment in control panel manufacture, public buildings, control equipment, process control and automation, defence and power network distribution.

INTER PANEL WIRING

Kochi RefineryCABLES

Kochi Refinery

a) 3 Core Cables are manufactured for critical space requirement, protection against rain-water and against ingress of small solid foreign bodies. These Cables are produced from best quality electrolytic copper, which is drawn, annealed on-life and bunched on automatic machines to ensure flexibility and uniform resistance. The conductors are insulated with a special grade of PVC on sophisticated co-extrusion lines.

MOTOR : 3 CORE CABLES

Kochi Refinery

b) 3.5core cablesare generally used for lighting applications & in the applications where the 0.5 core is used for neutral conductor because neutral conductor has almost no - load to carry, thus saving the cost, by using half conductor size.Neutral conductor is having half size in 3.5 core cable because neutral doesn't have to carry the load current .This is either used for unbalanced current (in Y-connection) or for earthing purpose which don't require high ampere rating.

FEEDER : 3.5 CORE CABLES

Kochi RefineryXLPE CABLES

Cross-linked polyethylene, commonly abbreviatedPEXorXLPE, is a form ofpolyethylenewithcross-links. It is formed into tubing, and is used predominantly inbuilding servicespipework systems, radiant heating and cooling systems, domestic water piping, andinsulationfor high tension (high voltage) electrical cables. XLPE-insulated cables have a rated maximum conductor temperature of 90C and an emergency rating up to 140C, depending on the standard used. They have a conductor short-circuit rating of 250C. XLPE has excellentdielectricproperties, making it useful formedium voltage10 to 50kV AC, andhigh voltage cablesup to 380kV AC-voltage.

Kochi RefineryPVC CABLES

PVC is commonly used as theinsulationon electricalcables; PVC used for this purpose needs to beplasticized.In afire, PVC-coated wires can formhydrogen chloridefumes; the chlorine serves to scavengefree radicalsand is the source of the material'sfire retardance. While HCl fumes can also pose a health hazardin their own right, HCl dissolves in moisture and breaks down onto surfaces, particularly in areas where the air is cool enough to breathe, and is not available for inhalation. Frequently in applications where smoke is a major hazard (notably in tunnels and communal areas) PVC-free cable insulation is preferred, such aslow smoke zero halogen(LSZH) insulation.

Kochi RefineryAUTO CHANGE-OVER SCHEME

Kochi RefineryAUTO CHANGEOVER SCHEME

Kochi RefineryFLOW CHART

Kochi RefineryCONTROL SUPPLY

Kochi Refinery

Control Supply to PMCC is 110 V dc and is fed from DCDB ( Direct Current Distribution Board)The DCDB is fed from battery charger in the substation.The battery charger has a battery bank as back-up in case of supply failure to the charger.CONTROL SUPPLY

Kochi RefinerySINGLE LINE DIAGRAM

11kV SWGR3.3 kV SWGRPMCCMCC11kV / 3.3kV11kV / 3.3kVIncomer-1Bus CouplerIncomer-211kV / 0.433kV11kV / 0.433kV

Kochi RefineryTHANK YOU

Kochi Refinery