transient stability analysis on ahts vessel … · result was that the closed bus of 2 generator...

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International Journal of Mechanical Engineering and Technology (IJMET)

Volume 10, Issue 02, February 2019, pp. 461-475, Article ID: IJMET_10_02_048

Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=2

ISSN Print: 0976-6340 and ISSN Online: 0976-6359

© IAEME Publication Scopus Indexed

TRANSIENT STABILITY ANALYSIS ON AHTS

VESSEL ELECTRICAL SYSTEM USING

DYNAMIC POSITIONING SYSTEM

Sardono Sarwito

Doctoral Program, Department of Marine Engineering,

Institut Teknologi Sepuluh Nopember, Surabaya, 60111, Indonesia

Semin

Professor of Marine Engineering, Department of Marine Engineering,

Institut Teknologi Sepuluh Nopember, Surabaya, 60111, Indonesia

Muhammad Badrus Zaman

Department of Marine Engineering, Institut Teknologi Sepuluh Nopember,

Surabaya, 60111, Indonesia

Soedibyo

Department of Electrical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya,

60111, Indonesia

ABSTRACT

The addition of dynamic positioning system on offshore auxiliary vessels leads to

the installation of a large powered bow thruster. Unpredictable fieldwork conditions

lead to uncertain loading. Changes in electrical system configuration and load

shedding scheme are just a few of the many ways to maintain electrical system

stability. This method is done in order to balance the generator mechanical power

generated with the load needs. The configuration changes has been made and the

result was that the closed bus of 2 generator thruster and 2 diesel generator

configurations have excellent stability that can reach stable conditions with 110%

loading on each bow thruster. While Rhe closed bus configuration of 1 thruster

generator and 2 diesel generator provides an opportunity to rest 1 generator thruster

to save generator usage. However, the stability of this configuration can be improved

by conducting a load shedding scheme

Keywords: Dynamic positioning system, transient stability, system configurations,

load shedding.

Transient Stability Analysis on AHTS Vessel Electrical System using Dynamic Positioning

System


Cite this Article: Sardono Sarwito, Semin, Muhammad Badrus Zaman and Soedibyo,

Transient Stability Analysis on AHTS Vessel Electrical System using Dynamic

Positioning System, International Journal of Mechanical Engineering and

Technology, 10(2), 2019, pp. 461-475-.

http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=2

1. INTRODUCTION

Anchor Handling Tug Supply (AHTS) vessel is a ships that assigned specifically to support

offshore work generally required to install a system that make them different from any other

ships [1]. Reviewing the field conditions and the level of accuracy needed at work, the ships

must be equipped with a dynamic positioning system, a system that serves to control the ship

movement [2].

Uncertain field condition correspond to environmental factor can cause a system to run

into failure, more over on a ship which used closed bus configuration [3]. This failure can be

cause by some interference, whether it is short term (transient) or interruption which has

longer disturbance time. An electrical system is prone to interference, therefore the system

needs to have the ability to maintain its sync condition. This ability is called transient

stability. This transient stability disturbance can occur on ships equipped with dynamic

positioning system in case of overload on one generator, motor starting, and also short circuit

on component.

The addition of a large powered bow thruster can affect system stability if the system does

not have resistance to transient disturbances that are temporary. In the event of a transient

disturbance and the system cannot maintain its stability, there has been be a loose

synchronization of the generator and more fatal has been cause failure of the electrical system

[3].

Objective of this paper is to analyze the transient stability on AHTS vessel electrical

system using dynamic positioning system. The study of transient stability has been provided

an assessment of the stability of the ship's electrical system so that practitioners can find a

way out of the problem. Some ways to prevent the occurrence of stability problems is to

change the system configuration and also by conducted load shedding when the motor with a

large power has been do the starting.

2. POWER SYSTEM STABILITY

2.1. Vessel with Dynamic Positioning System’s Electrical Stability

In general, a ship that equipped with a DP system possess much larger numbers of thruster

than vessel that not equipped with DP systems. The addition of this thruster resulted in a

significant increase in electrical load so it is necessary to add an extra electrical power source

to the vessel.

The classification of the DP system differentiates the system into 3 classes, one of which

is in terms of system redundancy [2]. This difference results in different configurations of

power systems on board equipped with a DP system to minimize the risk of system failure

due to interference with the power system [2].

In general, the ship has an electrical system with a closed bus configuration, a

configuration that can put all buses in connected state. The point is an electrical system that

allows one and more power plants to supply all loads on the ship. To maximize fault tolerance

in DP systems, electrical systems are designed generally separately (islanded) to reduce the

possibility of system disruption due to a single error. Unlike systems designed to use closed

Sardono Sarwito, Semin, Muhammad Badrus Zaman and Soedibyo


buses, the design of a split bus configuration has been impact only on the affected bus,

effectively isolating the problem in the affected area only. The goal is to avoid system failure

due to a mistake in which the entire system can experience blackouts by isolating failures on

only one redundancy system [3].

2.2. Definition of Stability

The stability of the electric power system can be defined as the ability of the electric power

system to be in normal condition when interference occurs [4].

Based on the IEEE Transactions On Power Systems paper entitled Definition and

Classification of Power System Stability, the stability of the electric power system is

categorized into three (1) Voltage stability; (2) Frequency stability; (3) Rotor angle stability.

Figure 1 Classification of Stability [4]

2.2.1. Voltage Stability

Voltage stability is the ability of the power system to maintain the voltage conditions on all

buses in order to remain stable after an interruption. Voltage stability is related to the ability

of the system to maintain the stability between the supply of the power plant and the load

requirements on the vessel. Disturbance in the voltage usually occurs due to the release of a

significant load resulting a voltage drop. The stability of this voltage is influenced by large

and small disturbances in the short and long term.[5]

Major disruptions for example are loss of generation or lost synchronization of the

generator and short circuit on the system. While minor disturbances are like the addition of

small-scale load so the system seeks to improve itself.

2.2.2. Frequency Stability

Frequency stability is related to the ability of the power system to maintain steady-state

frequencies with a nominal range following some system disturbances due to the imbalance

between the plant and the load. This is dependent on restoring the balance between load and

generating systems by minimizing the amount of discharges / losses. The frequency condition

must be stable to keep the system from losing sync [5] .

Frequency stability can occur in the short and long term. For the short term usually the

imbalance occurs due to changes in loads that cannot be adjusted by the generator. While

long-term disturbance is the loss of governor's control ability.


System


2.2.3. Rotor Angle Stability

Rotor angle stability is the stability associated with synchronous machine capability (in this

case the generator) connected to the power system to remain in sync condition after

interruption. The stability of the rotor angle depends on the ability to restore the equilibrium

between the electromagnetic torque and the mechanical torque of each machine on the

system. The instability can cause an increase in the angle of the swing on the generator

resulting in losing synchronization with other generators. The stability of the rotor angle is

divided into two, namely the stability of the small disturbance (steady state) and the stability

of the transient state.[5-8].

According to the study of transient stability has a period of 3-5 seconds after interference.

As for the stability of small disturbances havea period of 10-20 seconds after the interference

2.3. Standards Related to Transient Stability

Analysis of transient stability in AHTS ship electrical system with dynamic positioning

system is done by using simulation software to find out system response when transient

disturbance occurs. Regulations on system stability have been issued by international agencies

and used as reference by related industries.

International standards concerning the limits of operating voltage on electrical systems

have been issued by IEEE standard 1195 as follows:

Figure 2 Standard operating voltage limits of transient stability [4]

While in the marine industry, the government authority of this standard is the

classification body (classification society). Some countries have their own classification

society and have standards that refer to international standards. The AHTS BNI Castor ship

that became the object of this final project is an Indonesian-flagged vessel sailing in

Indonesian waters, the vessel is regulated by Indonesia's classification society BKI (Badan

Klasifikasi Indonesia). Given that the ship was built to the ABS issued standard (American

Bureau of Shipping), that is to say, it has a double class of BKI and ABS.

The standards governing the limits of voltage and frequency operations in both transient

conditions and their stable conditions are listed in ABS Rules Part 4: Vessel Systems and

Machinery Chapter 8 Section 3 in the table below [6].



Table 1 Variations of Frequency and Voltage According to American Bureau of Shipping Standard

Voltage and Frequency Variations

for AC Distribution Systems

Quantity in

Operation

Permanent

Variations

Transient Variations (Recovery

Time)

Frequency ±5% ±10% (5s)

Voltage +6%, -10% ±20% (1.5s)

3. METHOD

Before performing a transient stability simulation using the software, a single line diagram of

the AHTS vessel must exist as a reference for performing redrawing in the software.

Referring to the single line diagram, a system replication is drawed in the simulation software

according to the equipment specifications contained in the wiring diagram.

After the system is fully illustrated, the simulation of transient stability can be done by

using Transient Stability module in the software.

The results obtained from the simulation is the data in the form of voltage and frequency

per time unit. This data has been then be processed and analyzed so that the assessment of the

stability of the system can be done.

The simulation was run by conducting 2 study cases, motor starting and load shedding

action. The system later to be set into 6 different scenarios of configuration stated on the

Table 2. and by performing load shedding in the last scenario due to its configuration that

allows system to put 1 generator on standby. The load shedding scheme was done to improve

the system stability into its maximum ability.

Table 2 Simulations Scenarios

Scenario Power Supply Load Load Variations

1 2 Generator Thruster (Split Plant) 2 Bow Thruster

60% - 75%

100% - 80%

100% - 100%

110% - 110%

2 2 Generator Thruster (Closed Bus) 2 Bow Thruster

60% - 75%

100% - 80%

100% - 100%

110% - 110%

3 1 Generator Thruster (Split Plant) 2 Bow Thruster

40% - 40%

50% - 50%

60% - 60%

4 2 Generator Thruster, 1 Diesel

Generator (Closed Bus)

2 Bow Thruster & Ship

Equipment Load

60% - 75%

100% - 80%

100% - 100%

110% - 110%




Equipment Load

60% - 75%

100% - 80%

100% - 100%

110% - 110%




Equipment Load

75% - 75%

80% - 80%

85% - 85%

7

1 Generator Thruster, 2 Diesel

Generator (Closed Bus) with Load

Shedding

2 Bow Thruster &

Essential Load

80% - 80%

85% - 85%

90% - 90%


System


4. RESULT AND DISCUSSION

To get an electrical system that has high stability, there are several ways that can be done. In

this final project has been be simulated changes in electrical system configuration and also

designing the load shedding scenario to improve the stability of electrical system.

A case study designed to assess the stability of a system is a starting bow thruster that has

high power in various configurations that may be applied in the system. Configuration

scenarios and variations of bow thruster loading can be seen in Table 2.

The results of the following simulations are summarized per scenario as shown in Table 3

and so on.

Table 3 Voltage and Frequency Responses of Scenario 1 Bus C Summary

Simulation 1

No Variation f min

(%)

f steady

state (%) Bus

v min

(%)

v max

(%)

v steady

state (%)

Condition

f v

1 60% - 75% 97,513 97,513 C 98,7963 100,286 99,9106 Normal Normal

2 100% - 80% 95,8057 95,8057 C 96,1454 101,043 99,7611 Normal Normal

3 100% - 100% 95,8057 95,8057 C 96,1454 101,043 99,7611 Normal Normal

4 110% - 110% 95,2943 95,3122 C 77,1395 140,297 - Normal Drop

Voltage and frequency response in the split plant configuration scenario 1 thruster

generator for each bow thruster shows that all load variations up to 100% load on the bow

thruster can be borne by the system stably. Over 100% loading on each bow thruster results in

stability of the system being disrupted. This is because the thruster generator can only provide

power reserves for the start of the generator up to 100% load, above that value the generator

cannot provide enough starting from the bow thruster.

Figure 3 Voltage Response of Scenario 1 Variation 4

On bus C, transient conditions occur due to starting bow thruster where the voltage

experienced up and down from seconds to 2.01 then tend to be decreased dramatically to the

value of 77.14% in seconds to 3.21 and then jumped dramatically to the point of 140.3% in

seconds to 3.61. This condition does not conform to the ABS standard which states that the

tolerance of the voltage values under transient conditions is only allowed up to 20% above or

under stable conditions as well as recovery time of 1.5 seconds cannot be satisfied by the

system. In addition, the system also cannot reach a stable state because the voltage continues



to oscillate between the values of 104.35% and 88.82% during the simulation. While on the

bus D, there is a similar transient condition due to starting bow thruster where the voltage

experienced up and down from seconds to 2.01 then tend to be decreased drastically to the

value 77.14% in seconds to 3.21 and then jumped dramatically to the point 140.3 % in

seconds to 3.61. This condition does not conform to the ABS standard which states that the

tolerance of the voltage values under transient conditions is only allowed up to 20% above or

under stable conditions as well as recovery time of 1.5 seconds cannot be satisfied by the

system. In addition, the system also cannot reach a stable state because the voltage continues

to oscillate between the values of 104.35% and 88.82% during the simulation.

Figure 4 Frequency Response of Scenario 1 Variation 4

Frequency response on bus C indicates the existence of transient conditions due to the

starting bow thruster where the frequency decreased up to the value of 95.31% and directly

stable at that value. The value is still in accordance with the standards allowed so the system

is still allowed to operate. While the frequency response on bus D indicates the existence of

transient conditions due to starting bow thruster where the frequency decreased up to the

value of 95.31% and directly stable at that value. The value is still in accordance with the

standards allowed so the system is still allowed to operate.

Table 5 Voltage and Frequency Responses of Scenario 2 Summary

Simulation 2

No Variation f min

(%)

f steady

state (%) Bus

v min

(%)

v max

(%)

v steady

state (%)

Condition

f v

1 60% - 75% 97,196 97,196 C,D 98,6027 100,508 99,8 Normal Normal

2 100% - 80% 96,2364 96,2364 C,D 98,0374 100,97 99,8 Normal Normal

3 100% - 100% 95,8057 95,8057 C,D 96,1454 101,043 99,7 Normal Normal

4 110% - 110% 95,294 95,3312 C,D 77,1395 140,297 - Normal Drop

Voltage and frequency response in the split plant configuration scenario 2 thruster

generators for 2 bow thruster shows the same result with the first configuration that all load

variations up to 100% load on the bow thruster can be borne by the system stably. Over 100%

loading on each bow thruster results in stability of the system being disrupted. This is because

the paralleled thruster generator can only provide power reserves for the start of the generator

up to 100% load, above which the generator cannot provide enough starting from the bow


System


thruster. This happens because the ratio of the amount of power generators can generate with

the data required by the load is still the same as in the previous configuration.


In the connected bus there is a transient condition due to the starting bow thruster where

the voltage rises up from seconds to 2.01 then ten to be decrease drastically to the value of

77.14% in seconds to 3.21 then jumped dramatically to the point of 140.3% in seconds to

3.61. This condition does not conform to the ABS standard which states that the tolerance of

the voltage values under transient conditions is only allowed up to 20% above or under stable

conditions as well as recovery time of 1.5 seconds cannot be satisfied by the system. In

addition, the system also cannot achieve a stable state because the voltage continues to

oscillate between the values of 111.98% and 88.66% during the simulation.


Frequency response on the bus that connected indicate the existence of transient

conditions due to starting bow thruster where the frequency decreased up to the value of

95.33% and directly stable at that value. The value is still in accordance with the standards

allowed so the system is still allowed to operate.


Simulation 3

No Variation f min (%) f steady state

(%) Bus v min (%) v max (%)

v steady

state (%)

Condition

f v

1 40% - 40% 96,6644 96,6644 C, D 98,2131 100,811 99,8 Normal Normal

2 50% - 50% 95,8057 95,8057 C, D 96,1454 101,043 99,7 Normal Normal

3 60% - 60% 95,3719 95,3721 C, D 7,09637 118,03 99,7 Normal Drop



Configuration of split plant 1 thruster generator to bear 2 bow thruster arranged to achieve

the purpose of saving the use of generator. However, the two connected C and D buses are

split with buses A and B supplied by diesel generators. In this scenario we get 1 thruster

generator savings of 800 kW, but due to power cuts of 800 kW, the loading on the bow

thruster cannot be maximized. The voltage and frequency response in this configuration

indicates that the system can only maintain stable conditions up to 50% loading on each bow

thruster. This is actually in line with the two previous configurations because the power

supply comparison and load requirements show the same value. In the two previous

configurations the total supply is 1600 kW with 1030 kW of power requirement, whereas in

this configuration the total supply is 800 kW with a power requirement of 515 kW.


In the connected C and D buses, there is a transient condition due to the starting bow

thruster where the voltage undergoes a considerable ups and downs before reaching a high of

118.03% at 3.41 seconds and the lowest 7.09% at 4.01 seconds oscillations between values of

106.56% to 93.56%. Then the system can reach steady state condition at 99.7%. In this

condition, the voltage deviation is not in accordance with the ABS standard which states that

the tolerance of the voltage value under transient conditions is allowed up to 20% above or

under stable conditions, the system cannot meet the recovery time of 1.5 seconds so that the

system continues to experience voltage oscillations before reaching a stable condition at 30

seconds.


Frequency response on bus C and connected bus D indicates a transient condition due to

the starting bow thruster where the frequency decreases up to 95.37% and is directly stable at


System


that value. The value is still in accordance with the standards allowed so the system is still

allowed to operate.


Simulation 4

No Variation f min

(%)

f steady

state (%) Bus

v min

(%)

v max

(%)

v steady

state (%)

Condition

f v

1 60% - 75% 98,1305 98,1305 A,B,C,D 98,4459 101,402 99,8 Normal Normal



4 110% - 110% 96,9195 96,9208 A,B,C,D 89,7744 106,223 - Normal Drop

Configuration of closed bus 2 thruster generator with 1 diesel generator is designed by

connecting all buses on the system with the supply of 3 generators. This configuration saves

the use of 1 diesel generator of 350 kW. Power supply cuts of 350 kW did not significantly

affect the total load of bow thruster. Voltage and frequency response of all variations indicates

that the system is still categorized as stable up to 100% loading on each bow thruster.

However in the 110% load variation the system is classified as unstable from being unable to

meet recovery time. The voltage and frequency response drift in this configuration is still

relatively safe, but long time to bear the voltage oscillation can cause the accumulation of heat

on the equipment so it can be categorized as unsafe for electrical equipment.


On the connected bus there is a transient condition due to the starting bow thruster where

the voltage rises down from seconds to 2.01 until it touches the lowest point at 89.77% in

seconds to 3.01 then and the highest point at 106.22% at second to 4.01. For voltage rise and

fall values are still allowed according to the ABS standard which states that the tolerance of

the voltage values under transient conditions is allowed up to 20% above or under stable

conditions, but the system cannot meet the recovery time of 1.5 seconds so the system

continues to experience the voltage oscillation throughout the simulation. In addition, the

system also cannot achieve a stable state because the voltage continues to oscillate throughout

the simulation with a value between 106.1% and 94.08% even though near the end of the

simulation this deviation becomes smaller with a value between 100.16% and 99.26%.




The frequency response on the connected bus indicates a transient condition due to the

starting of bow thruster where the frequency decreases to 96.92% and is directly stable at that

value. The value is still in accordance with the standards allowed so the system is still allowed

to operate.


Simulation 5

No Variation f min

(%)

f steady

state (%) Bus

v min

(%)

v max

(%)

v

steady

state

(%)

Condition

f v





The configuration of the closed bus 2 thruster generator with 2 diesel generators is

designed by connecting all buses on the system with the supply of 4 generators. The voltage

and frequency response in this configuration is the best compared to the previous

configuration scenario because this configuration can maintain its stability up to 110%

loading on each bow thruster. This configuration can be used if you want to get maximum

loading from the bow thruster.



System


On the connected bus, a transient condition occurs due to the starting bow thruster where

the voltage rises and then falls within 0.6 seconds with the highest value of 102.31% at 2.01

seconds and the low of 97.51% at 2.61 seconds later can reach steady state condition at

99,7%. In this condition the voltage deviation value and its stable condition have met the

standard so that this condition can be classified as stable.


The frequency response on the connected bus indicates a transient condition due to the

starting bow thruster where the frequency decreases up to 97.71% and is directly stable at that

value. The value is still in accordance with the standards allowed so the system is still allowed

to operate.


Simulation 6

No Variation f min

(%)

f steady

state (%) Bus

v min

(%)

v max

(%)

v steady

state (%)

Condition

f v


2 80% - 80% 97,7734 97,7734 A,B,C,D 95,3904 103,648 - Normal Drop

3 85% - 85% 97,6186 97,6 A,B,C,D 77,9287 136,906 - Normal Drop

Configuration of closed bus 1 thruster generator with 2 diesel generator is designed by

connecting all buses on the system with the supply of 3 generators. This configuration saves

the use of a thruster generator of 800 kW. In contrast to the third configuration, a power

supply cut of 800 kW can be covered because it is aided by the backup power of 2 diesel

generators. The voltage and frequency response of all load variations indicates that the system

can maintain its stability up to 75% loading on each bow thruster. This value is 25% larger

than the configuration scenario 3 because the backup power to accommodate the starting bow

thruster is available from 2 diesel generators. Over 75% loading on each bow thruster causes

the system to become unstable.




On the connected bus transient conditions occur due to starting the bow thruster where the

voltage experienced up and down from seconds to 2.01 to touch the lowest value at the point

77.93% in seconds to 4.21 then the highest value at the point 136.91% in seconds to 5.01. In

this condition, the voltage deviation is not in accordance with the ABS

standard which states that the tolerance of the voltage values under transient conditions is

allowed up to 20% above or under stable conditions, the system cannot meet the recovery

time of 1.5 seconds so the system continues to experience the voltage oscillation until the end

of the simulation even though the deviation value decreases.


Frequency response on the connected bus indicates a transient condition due to the starting

bow thruster where the frequency decreases up to 97.62% and is directly stable at that value.

The value is still in accordance with the standards allowed so the system is still allowed to

operate.


Simulation 7

No Variation f min

(%)

f steady

state (%) Bus

v min

(%)

v max

(%)

v steady

state (%)

Condition

f v





System


The configuration in this scenario is the same as configuration 6 but continues with a

non-essential load-loaded load. This load release is done to provide backup power to meet the

starting bow thruster requirement. The voltage and frequency response of this scenario

indicates that the system has grown by 15% from 70% to 90%. This condition is achieved

because the power obtained from the load release can be sufficient for starting bow thruster up

to 90% loading on each bow thruster. Any loading above 90% has been cause the system to

become unstable.


The load shedding is done simultaneously with the starting bow thruster at 2 seconds with

simulation time of 60 seconds. Visible changes from the previous results of the system only

experienced up and down the voltage for 0.6 seconds with the highest value of 100.04% in the

second second and the lowest value of 97.98% in seconds to 2.61 and then reached a stable

state on the value 99.8%. This value is categorized as stable by ABS standards and allowed to

operate. Overall a system with a configuration of 1 thruster generator and 2 diesel generators

can tolerate up to 90% loading on each bow thruster.


Frequency response on the connected bus indicates a transient condition due to the starting

bow thruster where the frequency decreases up to 98.32% and is directly stable at that value.

The value is still in accordance with the standards allowed so the system is still allowed to

operate.



5. CONCLUSION

Based on the research results that have been done, it can be taken some conclusions as

follows: (1) Modeling of AHTS ship's electrical system yields 6 different configuration

scenarios, ie split plant 2 thruster generator to supply 2 separate bow thruster, split plant 2

thruster generator to supply 2 bow thruster in parallel, split plant 1 thruster generator to

supply 2 bow thruster, closed bus 2 thruster generator and 1 diesel generator to supply all the

load on the ship, closed bus 2 thruster generator and 2 diesel generator to supply all the load

on the ship, and closed bus 1 thruster generator and 2 diesel generator to supply all the load

on the ship. (2) From 6 scenarios of AHTS vessel system configuration configuration with

dynamic positioning system under DP manouvering condition, closed bus configuration

scenario 2 thruster generator with 2 diesel generator can bear 2 bow thruster load up to 110%.

This condition can be achieved because the availability of power for the starting motor bow

thruster becomes larger due to the addition of 2 diesel generators. While the generator usage

savings materialized in the configuration scenario of closed bus 2 thruster generator and 1

diesel generator and configuration of closed bus 1 thruster generator and 2 diesel generator. In

the configuration scenario of closed bus 2 thruster generator and 1 diesel system generator

stable until 100% loading on each bow thruster, while in scenario 1 thruster generator and 2

diesel system generator stabilized up to 75% loading on each bow thruster. (3) In the closed

bus configuration scenario of 1 thruster generator and 2 diesel generator, the system stability

can be improved by non-essential load shedding on the system. The results can be seen in

scenario 7 release load, seen the progress of the system stability increased up to 90% loading

on each bow thruster.

REFERENCE

[1] G. Ritchie, Offshore support vessels: a practical guide, 1st. ed. London: The Nautical Inst,

2008.

[2] IMCA, “Guidelines for the design and operation of dynamically positioned vessels,”

IMCA, 2007.

[3] M. Roa, “Demonstration of fault ride through capability for closed bus operation on

dynamic positioning vessels,” 2016.

[4] IEEE, “Definition and Classification of Power System Stability IEEE/CIGRE Joint Task

Force on Stability Terms and Definitions,” IEEE Transactions on Power Systems, vol. 19,

no. 3, pp. 1387–1401, Aug. 2004.

[5] P. Kundur, Power System Stability and Control. California, CA: McGraw Hill, Inc., 1994.

[6] American Bureau of Shipping, Rules for Bulding and Classing Steel Vessels, Part 4 Vessel

Systems and Machinery. New York, NY: American Bureau of Shipping, 2016.

[7] S Sarwito, Semin, T Hidayaturrahman. Analysis of transient response first order and

second order theory in pneumatic control system using feedback instrument type

PCM140. ICAMIMIA, 2017.

[8] S Sarwito, Semin, M Hanif. Analysis of unbalanced load effect of three phase transformer

feedback 61-103 performance on the various connection windings, ICAMIMIA, 2017.

transient stability analysis on ahts vessel … · result was that the closed bus of 2 generator...

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