IMCA M 103 Flashcards
1
Q
What is a fully operational DP system?
A
It is a system able to reliably keep a vessel in position and/or heading when working up to the rated environment
2
Q
What does “a safe situation” mean?
A
means one where the work has or could immediately cease with no
serious consequences from the inability to maintain position and/or heading
3
Q
What are the Dynamic Positioning systems as per IMO circ 1580?
A
1) Power system;
2) Thruster system; and
3) DP control system.
4
Q
What is the definition of DP equipment class 1 as per IMO MSC.1580 ?
A
For equipment class 1, loss of position and/or heading may occur in the event of a single fault.
5
Q
What is the definitioof DP equipment class 2 as per IMO MSC.1580 ?
A
For equipment class 2, a loss of position and/or heading will not occur in the event of a single fault in any active component or system. Common static components may be accepted in systems which will not immediately affect position keeping capabilities upon failure
6
Q
Mention examples of active components or systems
A
generators, thrusters, switchboards, communications networks, remote controlled valves, etc
7
Q
Mention examples of static components
A
cables, pipes, manual valves, etc
8
Q
What is the definitioof DP equipment class 3 as per IMO MSC.1580 ?
A
For equipment class 3, a loss of position and/or heading will not occur in the event of a single fault in any active component or system. A single failure includes:
items listed above for class 2, and any normally static component assumed to fail
all components in any one watertight compartment, from fire or flooding
all components in any one fire sub-division, from fire or flooding.
9
Q
How the station keeping reliability is achieved?
A
by the use of fault-tolerant DP systems based on the principles of redundancy
10
Q
What is redundancy?
A
It is the ability of a component or system to maintain or restore its function when a single failure has occurred.
11
Q
How can redundancy be achieved?
A
by installation of multiple components, systems, or alternative means of performing a function.
12
Q
Why do class societies use FMEA for DP vessels?
A
To demonstrate the fault tolerance of DP systems, as appropriate to the equipment class of DP, during their design approval process.
13
Q
Report 3 elements that contribute to DP system Reliability
A
- Planned amintenance
- condition monitoring
- Annual DP trials
14
Q
What is the most effective way to ensure the good reliability of DP system? Provide examples.
A
Through design.
Exampls: specifying high reliability components, carriage of critical spare parts and reducing the number of fault paths that lead to a loss of redundancy
15
Q
Whot are the Key Elements of Fault-Tolerant Design?
A
Performance;
Protection;
Detection.
16
Q
Explain Performance?
A
Equipment intended to provide redundancy should be capable of its rated capacity or that which is assumed to be available in the event of a failure
17
Q
Explain Protection
A
Protection can be a combination of automatic systems, operator competency assurance and procedural barriers designed to prevent faults transferring between sub- systems of the DP system, with the result that there is a vulnerability to common cause failures.
18
Q
Explain detection
A
Detection methods should indicate when an essential system is no longer available or no longer has the capacity to carry out its function effectively
19
Q
How can we mitigate the vulnerabilities of common power closed bus tie systems ?
A
It can be mitigated by using advanced generator protection (AGP) systems which identify and isolate a range of generator faults not covered by standard protection arrangements
20
Q
What are thesupplemental studies that should be considered onf FMEA for vessels operating with closed bus ties?
A
- Harmonic distortion in the intact case and after the worst-case failure (WCF) of harmonic cancellation features;
- Transient voltage studies;
- Extended protection co-ordination studies covering all protective functions in the DP system, not only those in the electrical protection system including earth fault, voltage dip (caused by short circuit), and active & reactive load failures.
21
Q
What are the key process in testing the redundancy concept?
A
- Predict
- Prove
- Protect
22
Q
What does “predict” mean for the redundancy processe concept?
A
– the FMEA needs to be able to predict the failure modes
23
Q
What does “Prove” mean for the redundancy processe concept?
A
the DP FMEA proving trials needs to demonstrate that the FMEA correctly
24
Q
What does “Protect” mean for the redundancy processe concept?
A
the redundant systems within the DP system have the performance, protective functions, and detection features to defend the redundancy concept against failure modes
25
Regarding DP testing, how does the performance is tested?
Performances should be demonstrated in both the intact and various failed conditions
26
In DP class 3 vessesl, how are the redundant groups to be separated?
The redundant groups are to be separated by A60 fire subdivisions; watertight separation is required where there is a credible risk of flooding. Separation requirements for the DP control system include the provision of a separate DP control room containing at least one backup DP control system that mirrors the main DP control system and which can be engaged manually.
27
Besides DP control, propulsion, power generation, power distribution, what other systems have to maintain the DP systems level of fault tolerance and redundancy required for the DP equipment class
Auxiliary systems including, but not limited to, fuel oil, lubricating oil, hydraulic oil, sea water cooling, fresh water cooling, HVAC and compressed air are subject to classification society rules and applicable statutory requirements
28
What is the governor responsible for?
active power sharing (kW) and bus frequency control
29
What is the AVR responsible for?
regulate control bus voltage and reactive power sharing (kVAr). Failure of AVRs has been the cause of a significant number of blackouts.
30
How does the generators synchronise?
Each generator should be provided with an independent method of automatic synchronising which has an independent check sync facility.
31
How does The synchronises work?
The synchronises should be capable of connecting a generator during the voltage and frequency variations that follow the loss of a generator to mitigate the risk that surviving generators might not being capable of their rated capacity.
32
What are the types of protections
Selective protection
Non-selective protection
33
What is a Selective protection ?
It identifies the source of a fault and isolates it from the power system
34
What is a non-Selective protection ?
It cannot positively identify the source of the fault and simply disconnects circuits to remove exposure to the fault condition
35
What does the selective protection include?
Short circuit;
Earth fault.
36
What does the non-selective protection include?
Over and under-voltage;
Over and under-frequency;
Overload (where the entire plant is overloaded);
Over-speed;
Over and under-excitation;
Reverse power;
Current and voltage unbalance.
37
What is the power system concepts for most of DP Vessels?
Radial designs
38
What is the most commom power distribution system?
DC
39
How does the DC systems work?
the output of AC generators is rectified to DC and fed to a DC distribution system
40
What are the advantages of DC power?
Reduced fuel consumption and emissions
Fault currents can be controlled electronically
41
Mention one of the causes of malfunction on power systemss
Harmonic distortion
42
What are the main functions of PMS?
GENERATOR MANAGEMENT AND BLACKOUT RECOVERY
43
What is the most effevtive form of load shedding ?
by variable speed drive (VSD or VFD)
44
Mention the items which the blackout detection should be based on?
independent sources such as :
-voltage transducers,
-blackout relays
- generator circuit breaker status.
45
What types of failures are not acceptable for thrusters?
uncontrolled increase in thrust or change in thrust direction
46
What are the acceptable failures for thrusters
All failures must be fail safe as follows below:
* Fail as set;
* Fail to zero thrust;
* Drive motor trips.
47
What type of Thrsuter failure should be given an unambiguous alarm?
for a command/feedback deviation and not for a wire-break
48
Define VMS
Vessel management systems (VMS) are essentially:
remote control
monitoring and alarm systems for the vessel which include a range of automatic functions, and which may incorporate the PMS
49
Regarding DP control system for smal vessels, inform the 3 thrusters analogue signals
command, feedback and ‘ready for DP’ signals. Larger vessels tend to have a network interface to the thrusters.
50
Explain the minimum requirements for DP class 3 regarding DP controllers
2 controllers at the main DP station and 1 controller at the backup DP station with suitable physical separation between them (typically A60 bulkhead)
51
What is important to know regarding failure on Thruster Control Mode Selector?
1) No failure of the selector system should prevent manual control.
2)The control selector forms a common point between all thrusters
3)failure cannot cause the control mode to transfer from auto DP to another mode
For DP equipment class 3 vessels it is important to ensure no single failure of the control selector switch should cause control to transfer unexpectedly to the backup DP system
52
What is consequence analyser?
It is software function continuously verifying that the vessel will remain in position even if the worst-case failure occurs.
53
What does consequence analyser do?
Provides a warning if the vessel is not able to maintain position and/or heading after a predefined WCF has occurred during current operations and weather conditions. Additionally, the consequence analyser should perform calculations to verify that in the event of a single fault there is sufficient thrust available to maintain position and/or heading.
54
What is expected result to a failure on a extenal interface to DP.
Erroneous signals from position references, vessel sensors and other interfaces should be rejected before they can affect the DP control system
55
Regarding DP class 3 explain how the PRS should be assigned to DP backup system?
at least one position reference must be assigned to the DP backup system.
56
What protection device should be installed on antennas and external sensors?
lightning arresters
57
as per IMCA M 103 how shoud be the power suppply for IJS?
It should be powered from an uninterruptable source of power independent of the DP control system
58
In case of detection of gas or fire ina MODU which areas will have shutdown?
1. ventilation systems, except fans necessary for supplying combustion air to prime movers for the production of electrical power;
2. main generator prime movers, including the ventilation systems for these;
3. emergency generator prime movers
59
What are the design principles for ESD (emergency shutdown) systems on DP vessels?
-Individual shutdown buttons should be provided for each redundant machinery group, interfaced to dedicated field stations for that redundant group.
-There should not be a single overall ESD button
- There should be no cascade function from a higher level to lower levels
- The ESD system should not compromise the redundancy concept
- ESD field stations should be provided in numbers and locations which match the split in the redundancy concept
60
Regarding a vessel DP class 3, what are the 2.22.1 Requirements for Physical Separation?
consider the effect of the loss of all the equipment within one fire subdivision and/or watertight compartment to the effects of fire or flooding
DP class 3 requires physical separation between redundant groups, the separation is to have a specific fire and watertight rating.
61
Regarding 2.22.2 Fault Propagation out of Compartments what is important to know about UPS's?
UPSs should be designed to withstand a fault current and continue to operate selectively or without an unacceptable voltage dip.
62
What are the IMO Circulars DP vessels should meet in aspects of design according to year of build?
IMO MSC/Circ. 645 and IMO MSC/Circ. 1580
63
How is safety measured on DP Vessels
by the ability to maintain position and /or heading whist in automatic DP control
64
Which IMO Circulars are applicable for a DP vessel built in 2016.
It is applicable IMO circ 645 and section 4 from IMO cir 1580
65
What is associated with the severity of risks of DP operations?
The inability to maintain position and/or heading will vary according to the activity being undertaken
66
IMO MSC.1/Circ.1580 section 4 is applicable for all vessels regardless of year of build. What is the main concept of thsi section?
Th section 4 applies risk-based principles and establishes that DP vessels should be considered in terms of DP equipment class.
67
To whom the may DP documentation shoul be available?
To all revelvante members os the vessel crew (Key DP Personnel)
based technical management and superintendents
CDPA
68
As per IMCA M 103, inform operantion and requirement dada tha should be included on DP documentation
The safe and effective management of the vessel in DP;
The technical suitability of the vessel for each DP activity it is required to carry out;
The configuration for the CAM and the TAM;
The vessel’s station keeping capabilities following WCF
Compliance with appropriate standards and guidelines;
Training and familiarisation material to vessel crews.
68
69
Inform 5 examples of documents that should be onboard
DP system FMEA (updated since the original study)
DP FMEA proving trials (updated)
Annual DP trials
DP operations manual
Service reports concerning the DP system
70
What is the base date of annual DP trials ?
It Should be carried out within three months before or after each anniversary date of the initial DP FMEA proving trial. This may be changed to align with new DP FMEA proving trials following a major upgrade or conversion
71
What documents normally need Moc process when have Modifications and amendments
DP system FMEA
DP operations manual
72
What document that should be kept onboard permanently?
DP incident reports
IMPORTANT: ALL DP DOCUMENT RELATED TO INCIDENT REPORT MUST BE KEPT ONBOARD AS WELL(EXAMPLE CHECKLIST)
73
Why all DP vessels should undergo trials, tests, and checks ?
to verify their operability, integrity and fault tolerance when operating in DP mode
74
How can we verify the operability, integrity and fault tolerance of a DP vessl?
It should be carried out at regular, pre-planned intervals and should consider the planned industrial missions and WCF of the vessel
75
What is the most rigorous DP testing ?
DP FMEA proving trials
76
What is the purpose of DP FMEA proving trials?
provide evidence of redundancy and fault tolerance
77
What is the difference between FMEA proving trials and commissioning trials
FMEA Proving Trials: provide evidence of redundancy and fault tolerance
commissioning trials: demonstrate that systems and equipment meet the required functional specification
78
What should DP FMEA and proving trials CONFIRM?
-WCF design intent (WCFDI);
-WCF
79
What else DP FMEA and the proving trials should address ?
Identify the subsystems and equipment and modes of operation;
Identify all potential failure modes and their causes;
Identify single point failures;
Identify potential hidden failures;
Identify potential configuration errors;
Evaluate the effects on the DP system of each failure mode
80
What document should The annual DP trials programme should be based on?
DP FMEA proving trials
81
What are the means of conducting the DP trials?
annual or incremental basis
82
What sould be tested during annual DP trials?
All functions on which the redundancy concept depends, including network testing, blackout recovery plans and ESD functions
83
What are the categories of findings from annual DP trials ?
Category A – for immediate attention;
Category B – for action when reasonably convenient;
Category C – for future attention/consideration.
84
Who is responsible for development, conducting and ownership of all annual DP trials ?
the vessel owner/operator
85
When should the DPO repeat the the "DP Field Arrival checklist" when return to the field?
when the vessel returns to the field after an absence of more than 24 hours
86
What is the purpose of the DP Field Arrival checklist?
to ensure satisfactory operation of the DP system
87
How cna planning and control of DP operations be achieved?
by activity operational planning
88
What are the elements od DP activity operational planning?
CAM, TAM and ASOG
89
What is CAM?
Critical Activity Mode : tHE most fault-tolerant configuration for the DP system. For DP class 2 and 3 vessels the CAM will ensure that a single point failure does not exceed the vessel’s identified WCF
90
What is TAM?
Task Appropriate Mode : a risk based operating mode in which the DP vessel may be configured and operated such that a single point failure could result in exceeding the vessel’s identified WCF
91
In case of TAM, can we we just conisder that we can exceed the WCF?
No. A risk assessment should demonstrate that the consequences of exceeding the vessel’s identified WCF are acceptable
92
What is ASOG?
Activity Specific Operating Guidelines: defines the operational, environmental and equipment performance limits for the location and the specific activity the vessel is undertaking
93
What are CAM and TAM are related to?
CAM and TAM are related to system and equipment configurations of DP vessels
94
what elements are CAM, TAM and ASOG are based on to be created?
thorough knowledge of the DP system
DP FMEA
The industrial mission
Vessel location
Risk assessment
95
What does GREEN mean FROM CAM/TAM?
Normal operations – all systems and equipment fully operational, DP verification processes completed, and DP set up confirmed
96
What does BLUE mean FROM CAM/TAM?
Advisory status – where any of the GREEN conditions are not met
97
What is the response for BLUE status in CAM?
Conduct risk assessment to determine whether to continue, change position or cease operations
98
Explain the 4 colors of ASOG
GREEN: operating within acceptable performance limits
BLUE -ADVISORY STATUS: approaching performance limits or reportable alarm status.
Yellow - YELLOW STATUS: Reduced status pre-defined performance limits reached, component or system failure resulting in loss of redundancy
Emergency Status: Pre- defined operational or performance limits exceeded, component or system failure resulting in loss of control or position and or heading, internal or external emergency situation affecting the vessel
99
What is DP Capability Analysis?
It is the capability of the DP vessel to to maintain position and/or heading in defined equipment configurations and environmental conditions should be known; particularly station Keeping capability following its WCF
100
What should DP capability analysis should include?
Fully intact in power generation and thrusters
Loss of most effective thruster(s), after worst case failure.
101
How should the DP Capability Analysis be calculated?
for the intended area of operations and at current speeds of 0kts, 1kt and 2kts and any other expected current speed
102
How are the forces measured on DP capability analysis?
measuring thruster forces against environmental forces
103
How can capability analysis obtain a more accurate result?
By adding dynamic force interaction to the calculation
104
How can DP capability analysis be supplemented?
by real time measurements and observations to develop DP footprint plots
105
What are the best way for key DP personnel to obtain lessons learnt?
Vessels's emergency training exercises and IMCA’s DP incident reporting
106
What should be considered for the DP emergency exercises?
failure modes identified in the vessel’s DP FMEA
107
How are the station keeping events categorised ?
* DP incident
* DP undesired event
* DP observation
108
What is a DP incident?
A major system failure, environmental or human factor which has resulted in loss of DP capability
109
What is a DP undesired event
A system failure, environmental or human factor which has caused a loss of redundancy and/or compromised DP capability
110
What is a DP observation
An event that has not resulted in a loss of redundancy or compromised DP operational capability but is still deemed worthy of sharing
