2nd Plant Term Q's

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nibor222
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185649
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2nd Plant Term Q's
Updated:
2012-12-08 06:27:33
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second 1/2 of plant
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  1. What is WPP? Where is it used?
    WPP is Worker Protection Practices. It is used in all generating stations
  2. How are PSSP/WPP boundaries identified?
  3. AREVA has a PSSP/WPP boundary line on the station one line diagrams. This is not always the true boundary that the plant desk holds OR up to, so it is best to research the 1J-xxx-01 for the SOO boundaries.
    •  
    • A good example of this is MCA switchyard. One line boundary doesn’t match the 1J-MCA-01 PSSP/WPP boundaries for plant OR
  4. Who holds Operating Authority for the PSSP equipment at Integrated Generating Stations?
    Real Time Operations
  5. Who holds Operating Authority for the WPP equipment at Integrated Generating Stations?
    The generating station
  6. What is the procedure for establishing work protection for equipment identified on the station one-Line, located on the WPP side of the WPP/PSSP Boundary? Give an example.
    • The Plant Operator will assign Operating Responsibility to the PIC at the generator station.
    •  
    • For example: KCL G3 is going down for scheduled maintenance. Verify that they would like UTAI the unit disconnect 2D3. If they do tag the appropriate equipment with OR tag(s) then you assign them OR by stating “you now have OR of KCL G3 UTAI 2D3 as of xx:xx” and wait for the repeat back. Write the information in the logsheet and implement the CROW.
    •  
    • Before getting off the phone with the PIC check to see if you can block any of the alarms while they have OR of the unit.
  7. Who retains Operating Authority for SPN NPRF facilities?
    Field. As per 1J-11 it lies with Columbia Basin Generation
  8. Who retains Operating Authority for SEV NPRF facilities?
    Field. As per 1J-11 it lies with Columbia Basin Generation
  9. What is the process for assigning Operating Responsibility to a category “D” authorized worker for SEV SPOG01?
    Confirm equipment with category “D” worker. Log the OR in the log sheet and read to the PIC “you now have Operating Responsibility of SEV SPOG01 as of xx:xx” and write the time in the logsheet. Then go to the SEV spillway gates screen and click on the disable/enable button to hang an OR tag. Once the tag is hung be sure to implement the CROW
  10. Who retains Operating Authority of station service facilities at BC Hydro integrated generating stations?
    The generating facility staff has OA of the SS
  11. What is the procedure for assigning Operating Responsibility of station service facilities at generating stations?
    Confirm the equipment required with Category “D” worker. Write in logsheet and read “you now have OR of (station and equipment) UTAI (equipment) as of xx:xx” and write the time in the logsheet. Hang tag(s) on appropriate equipment. Implement CROW
  12. What is the process for assigning Operating Responsibility to a category “D” authorized worker for work on JOR SS1?
    Confirm the equipment required. Write in logsheet and read “you now have OR of JOR SS1 UTAI 25DSS1 as of xx:xx” and write the time in the logsheet. Hang OR tag on 25DSS1. Implement CROW
  13. Define an 86GS shutdown:
    86GS – Generator Standby Lockout Shutdown: This shutdown executes the same functions as 86G, except that initiation of the fire protection is not required
  14. Define an 86G shutdown:
    86G – Generator Primary Lockout Shutdown: The primary lockout shutdown initiates the fastest possible shutdown of the machine. It is operated only when the primary relay detects a major internal failure within the machine
  15. Define an 86N shutdown:
    86N – Normal Lockout Shutdown: Protection tripping through this device will be for conditions that require maintenance but do not require emergency shutdown
  16. Define a 5C shutdown:
    5C – Non-Lockout Unload Trip Without Overspeed: The function is intended primarily for non-urgent tripping, which allows slow unloading of the machine to permit load transfer to other machines. The machine is separated from the system but not shut down
  17. Define a 5B shutdown:
    5B – Non-Lockout Partial Shutdown to SNL Without Overspeed: This function shuts down the unit but the unit transformer breaker is not locked out, the machine can be immediately started and put back into service
  18. Define a 5A shutdown: 
    5A – Non-Lockout Partial Shutdown to SNL With Overspeed: This function operates for conditions which will be removed once the transformer breaker has been opened. It also operates when the transformer breaker may be accidentally tripped 
  19. What is the purpose of protection?
    The purpose of protection is to remove any faults from the system and prevent damage to equipment by these faults.
  20. What is the difference between a protection system and a protection scheme?
    A protection system is an individual protection arrangement, and the protection scheme is a coordinated combination of the protection systems.
  21. With regards to protective relaying, what is meant by the term – Selectivity?
    Only a minimum portion of the power system should be disconnected to isolate a fault
  22. With regards to protective relaying, what is meant by the term – Security?
    Schemes must be able to discriminate between signals which require action, and those that do not
  23. With regards to protective relaying, what is meant by the term – Reliability?
    Ability to operate without failure whenever a fault or abnormal condition exists
  24. With regards to protective relaying, what is meant by the term – Coordination?
    Schemes must relate to each other so they operate in the right order
  25. Provide two reasons why two sets of redundant protection are used on a piece of equipment. What are they named?
    Increased dependability and one protection may be removed for maintenance and the equipment will still remain protected. There is a primary protection and standby protection
  26. Typically in a fault condition, _______ will rise while _____ falls.
    The current will rise and the voltage will drop
  27. What are the two main reasons for utilizing instrument transformers?
    For metering and protection
  28. What is a VT? What purpose does it serve? What is its typical output?
    A VT is a voltage transformer. It provides meters, relays and controls a low voltage that is proportional to the system voltage. Typical output is 120V
  29. What is a CT? What purpose does it serve? What is its typical output?
    A CT is a current transformer. It provides meters, relays and controls a low current that is proportional to the system current. Typical output is 5A
  30. If a CT has a ratio of 2000:5, what is the primary current if the secondary current is 2.5 amps?
    1000 A
  31. With respect to a CT, what is burden? How does exceeding the burden impact the operation of a CT?
    Burden is the amount of load connected to the secondary of the CT and is expressed as an ohmic value. If the burden connected to the CT is too high there is a risk the CT could saturate. Once the CT saturates it can no longer accurately reflect system current.
  32. With respect to a VT, can the secondaries be opened with the VT energized? Explain any consequences.
    Yes the secondaries can be opened energized. Consequences would be that you are removing the protection that uses this VT to operate.
  33. With respect to a CT, can the secondaries be opened with the CT energized? Explain any consequences.
    NO!! This can cause a very high voltages and could possibly kill a worker or harm equipment.
  34. What is a protection zone? How is it typically defined?
    Protection zones are usually referred to by the system they protect. Since most relays monitor current, the boundaries of a protection zone are usually determined by the location of the CT’s.
  35. What is a tripping zone? How is it typically defined?
    A tripping zone is the section of the power system that is tripped by protection. The boundary of a tripping zone is determined by the breaker locations.
  36. With respect to protection, what is meant by the term overlap?
    To prevent any unprotected areas and to provide backup the protection zones are typically overlapped
  37. What is breaker fail protection?
    Breaker Failure protection initiates tripping if the fault current is still flowing through the breaker after a time elapses following the protection zone operation. Breaker Fail protection operates to trip the adjacent zone.
  38. What is the purpose of relay targets?
    Relay targets are used to record the operation of protective relays.
  39. What are symmetrical components? What is meant by positive sequence? What is meant by negative sequence? What is meant by zero sequence?
    • Symmetrical components are commonly used for analysis of three-phase electrical power systems. If the phase quantities are expressed in phasor notation using complex numbers, a vector can be formed for the three phase quantities.
    •  
    • A positive sequence means the current and voltage has a positive phase rotation ABC. Each phase is equal and 120° between them. Balanced.
    •  
    • A negative sequence has a negative phase rotation ACB and occurs in unbalanced situations due to unbalanced load.
    •  A zero sequence the phases are equal in magnitude and in phase. Path to ground.
  40. What two relays are used to detect stator phase to ground faults?
    Zero-sequence overvoltage relay and Third harmonic voltage differential relays
  41. What relay is used to detect stator phase to phase faults?
    Differential relays
  42. With respect to overspeed of an electrical generator, how is the unit protected?
    The unit is protected by an overspeed relay that will put the unit to SNL if tripped. This overspeed relay uses centrifugal speed switches or permanent magnet generator to monitor the speed and trip if required.
  43. With respect to motoring of an electrical generator, how is the unit protected? Are there any exceptions?
    Motoring is protected by a reverse power relay. This is disabled if the unit is in S/C.
  44. With respect to generating station step-up transformer, what protective relays are in place to detect fault conditions? Name both electrical protection and non-electrical protection.
    Differential protection and Ground differential protection. Gas relays, Sudden pressure relays, conservator low oil device, oil temperature, winding temperature and pressure relief devices
  45. What are the two acceptable methods for work on equipment in the WPP area that requires isolation in the PSSP area? Give an example of each explaining when each would be used?
    • Using GOI procedures:
    • The Control Centre PIC can issue a Guarantee of Isolation (GOI) to the WPP PIC on the PSSP area isolating devices.
    •  
    • GOI would be used if the work didn’t involve a piece of equipment in the PSSP, but required isolation from PSSP equipment
    •  
    • Using Transfer of Operating Authority procedures:
    • If the PSSP isolation device is within the generation switchyard then the Operator at the Control Centre can transfer Operating Authority up to and including the isolating devices in the switchyard to a worker on site authorized to category “D” using the procedures found in Appendix II of 1J-18. The on-site worker will then assume the role of PIC and is responsible for establishing work protection according to standard WPP procedures.
    •  
    • TOA would be used if the operation of equipment in the switchyard and PSSP boundary was required during the work process for the WPP worker.
  46. What are the two acceptable methods for work on equipment in the PSSP area that requires isolation in the WPP area? Give an example of each explaining when each would be used?
    • Using PSSP procedures:
    • The WPP PIC can issue a GOI to the Control Centre PIC on the WPP area isolating devices, following receipt of Operating Responsibility. The work can then be done using PSSP procedures.
    •  
    • GIO would be used if the work didn’t involve a piece of equipment in the WPP, but required isolation from WPP equipment
    •  
    • Using WPP procedures:
    • If the PSSP isolation device is within the generation switchyard then the Operator at the Control Centre can transfer Operating Authority to a worker on site using the procedures found in Appendix II of 1J-18. The on-site worker will then assume the role of PIC and is responsible for establishing work protection according to standard WPP procedures. If a GOI is required on remote PSSP area isolating devices to perform this work then it can be issued by the Operator at the Control Centre using GOI procedures.
    •  TOA would be used if the operation of equipment in the switchyard and WPP boundary was required during the work process for the PSSP worker.
  47. Describe the importance of detecting a field ground on a synchronous generator. What are the consequences of two field grounds on a synchronous generator? Which protective relay detects field grounds?
    • The field winding must produce symmetrical magnetic flux, otherwise the resulting machine unbalance will cause shaft deflection and vibration. Loss of symmetrical magnetic field can be caused by short circuiting.
    •  
    • Two field grounds in the field winding will cause a short-circuit unbalance.
    •  
    • 64 ground detector relay is the protective relay used for this detection
  48. What is a Remedial Action Scheme? What is its purpose?
    • An automatic protection system designed to detect abnormal or predetermined system conditions, and take corrective actions other than and/or in addition to the isolation of faulted components to maintain system reliability. Such action may include changes in demand, generation (MW and Mvar), or system configuration to maintain system stability, acceptable voltage, or power flows.
    •  
    • The purpose of the RAS actions is to mitigate an undesirable effect of the contingency on the power system.
  49. What is the most typical RAS scheme? What is its purpose?
    Generation Shedding. Generation Shedding is required to maintain angular stability of the bulk transmission.
  50. How is Generation Shedding armed? How are Plant Operators made aware of generation shedding being armed?
    • Generation Shedding is the responsibility of the TC and is automatically armed through the Energy Management System Advanced Application, TSA-PM.
    •  
    • Units that are armed have a small flashing ‘C’ by the unit breakers.
  51. What alarms may be received on a Gen Shed operation? What is your response to units tripping from Gen Shed operations?
    • Gen Dump Received (SEV, MCA, REV)
    • LATEST_ACTXX (KCL), where XX is the unit #
    •  
    • Should follow the instructions in 7T-10
    •  
    • Before re-synching KCL units you must contact the TC.
    •  
    • All other units should be re-synched and loaded to 10% and then ask GC where they’d like it loaded to.
    •  
    • If serving local load with a generator, you must get appropriate Grid/Load permission.
  52. What Operating Order documents Station Alarms policy?
    The Local Operating Order 3G-XXX-02x where XXX is station and x is A or sometimes B
  53. What is the primary difference between station alarms and analog alarms?
    • Station alarms are triggered at the station and sent from the generator station themselves to the EMS system alarm program.
    •  
    • Analog alarms are set in the EMS system and alarm when readings from the stations go outside the alarm limits. JHT Plant total alarms are a good example.
  54. Who determines the priorities for alarms at BC Hydro Generating Stations? In which document can you verify the alarm priorities for SEV generating station?
    • The alarm priorities are determined by BC Hydro Generation Line of Business (GLoB)
    •  
    • You can verify alarm priorities for SEV in 3G-SEV-02
  55. What are the priorities and appropriate response for all generating station alarms?
    • P1 – This is a device operation alarm
    • P2 – Is an analog alarm that requires immediate operator response
    • P3 – Urgent Requires immediate maintenance response, must call field staff 24/7
    • P4 – Semi-urgent requires maintenance response during 0800-2200 7-days a week
    • P5 – Non-urgent requires next working day response. Enter in CROW
    • P6 – Information messages


    • P7 – Nuisance alarms moved to P7
    • P8 - Spare
  56. What is the primary difference in callout procedures for emergency situations versus non-emergency conditions at BC Hydro generating stations?
    • In an emergency situation where it is necessary to preserve public health and safety, preserve the reliability of the transmission system, limit or prevent damage to property or the environment or to expedite restoration of service, the BCH operator will first call crews by following the callout list (COPS) and call the standby manager at the first opportunity.
    • 3
    • In a non-emergency condition, the standby managers shall be contacted first
  57. What can single generating unit trips be caused by? What is the Plant Operators response?
    • Single unit trips are generally caused by unit protection operations or gen shed.
    •  
    • There are 4 key responsibilities of the Plant Operator when this occurs. They are:
    •  
    • 1)     Respond to any water flow issues while adhering to ramp rates and minimum flows
    • 2)     Aid the GC in replacing generation if required
    • 3)     Aid the TC and any Grid Operators in any corresponding voltage issues
    • 4)     Investigate the cause of the outage, report the forced outage to PSOSE and Plant Manager (STBY MGR after hours) and log in CROW
  58. What can multiple generating unit trips be caused by? What is the Plant Operators response?
    • Mulitple unit trips are typically due to gen shed or protections at the station other then the individual generator protection.
    •  
    • Support the GC, TC and Grip Operators to ensure reliability of the BES. If a result of gen shed re-synch shed units to 10% and not load until discussion with TC and GC.
  59. What is an islanding event? What can the Plant Operator expect to happen in an islanding event?
    • An island is defined as a pocket of generation and load operating at a given frequency. For example a generator and load is not connected to the BES.
    •  
    • The Plant Operator lacks the situational awareness when an islanded event occurs. The GC, TC and Grip Operators are aware of islanded events through alarms. They should notify the Plant Operator who will not make generation changes in the island without their direct approval.
  60. What is blackstart? When may a Plant Operator be asked to blackstart a generating station? What is the typical blackstart procedure?
    • A blackstart is when there is no external source of SS.
    •  
    • The Plant Operator may be asked to blackstart a generating station when an area has an outage and cannot be restored. For instance 2L101 kicks out and will remain out you blackstart RPG.
    •  
    • Typical blackstart procedure depends on the blackstart unit. If it is capable of remote blackstart then:
    •  
    • - Obtain a source of station service (typically local diesel generation)
    • - Put an auto-start on the unit(s)
    • - Open all generating station switchyard CBs
    • - Close generator unit CBs to energize the step-up transformer
    • - Synchronize enough generators to one another as directed by the System Operator
  61. Where does BC Hydro have remote blackstart capability?
    ASH, CMS, COM, MCA, REV & RPG
  62. What is the only type of Environmental Incident the Plant Operator is responsible to report?
    Any violations relating to water conveyance
  63. What is a Water Conveyance instruction? Who typically initiates all Water Conveyance instructions?
    A water conveyance instruction is an instruction to either increase or decrease a spill at an NPRF. PSOSE sends these instructions through CM.
  64. Where are all Water Conveyance instructions recorded?
    In CM
  65. Who maintains Operating Responsibility of SEV generating stations NPRFs? Why?
    Real Time Operations maintains OR of the SEV spill gates because we have supervisory control and we need to spill in the event of a dam breach at Boundary Dam
  66. Can a BC Hydro Control Centre operator operate a NPRF facility without first notifying PSOSE? What must be done if the operation is done without a Water Conveyance instruction?
    Yes the plant operator can operate NPRF facilities without first notifying PSOSE. Once the operation is completed it must be entered into CM. Create a water conveyance, enter the information and then save.
  67. What is the purpose of the paper based log?
    To record any information that isn’t captured by EMS or CROW.
  68. What types of details are recorded in the paper based log?
    Operating Responsibilities, Critical Water Levels, Callout Numbers, Shift Change Notes and Entry/Exits and Manchecks
  69. What are the operators and apprentices responsibilities associated with the paper based log?
    The operator and the apprentice must sign the log at the beginning of their shifts to assume the shift duties for that assigned portion of the power system associated with that operating desk.
  70. What does SCADA stand for? Explain SCADA.
    Supervisory Control and Data Acquisition. SCADA is used for the remote control and data recording of equipment and parameters in the control system
  71. What are the four key functions of SCADA? Define each.
    • 1)    Telemetry: giving us readings like MW, MVAR, Voltage, etc information passed through RTU
    • 2)    Status Reporting: Reporting the change of status of a device at a remote facility
    • 3)    Alarm Reporting: Reporting of unusual conditions programmed as alarms through RTU
    • 4)    Supervisory Control: Allows operations of equipment at remote facilities
  72. What are the three major components of a SCADA system? Define each.
    • 1)    A master station: The master station consists of a computer with the input/output equipment needed to transmit control measures to the remote units and to receive information from them. All operator initiated operations (remote) of a RTU are made through the master unit and are reported back to the master from the RTUs. This report back works whether the command was successful or not. If it was successful, the RTU will report back the status change.
    • 2)    Remote Terminal Units (RTUs): RTUs are located at selected stations, and are either wired to perform certain pre-determined functions or are microprocessor based with both memory and logic capabilities. On a command from the master unit, the RTU will send commands to the appropriate device to make the requested status change. If the control is successful, the RTU will report back the status change. Transducers in the RTU convert quantities such as voltage and current to DC or voltage proportional values for communication to the Control Centres.
    • 3) A communication facility: Signals between the Master Station and the RTUs are sent across communication facilities for supervisory control, telemetry and alarm reporting. The communication means is typically microwave; however other systems are also used such as Power Line Carrier.

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