click here to download - UniKL MIMET Official Website

More documents

Recommendations

Info

MIMET Technical Bulletin Volume 1 (2) 2010 Feature Article 7 OBSERVATION ON VARIOUS TECHNIQUES OF NETWORK RECONFIGURATION WARDIAH DAHALAN* Department of Marine Electric and Electronics Technology Malaysian Institute of Marine Engineering Technology, Universiti Kuala Lumpur Received: 27 May 2010; Revised: 2 August 2010 ; Accepted: 12 October 2010 ABSTRACT The shipboard power system supplies energy to sophisticated systems for weapons, communications, navigation, and operation. After a fault is encountered, reconfiguration of a shipboard power system becomes a critical activity that is required to either restore service to a lost load or to meet some operational requirements of the ship. Reconfiguration refers to changing the topology of the power system in order to isolate system damage and/or optimize certain charac‐ teristics of the system related to power efficiency. When finding the optimal state, it is important to have a method that finds the desired state within a short amount of time, in order to allow fast response for the system. Since the reconfigu‐ ration problem is highly nonlinear over a domain of discrete variables, various techniques have been proposed by the researchers. The main tasks of this thesis include reviewing the shipboard power system characteristics, studying and reviewing shipboard power system integrated protection, shipboard power distribution systems and typical loads of ship‐ board power system. A variety of techniques used in previous works have been explained in methodologies review. Many criteria and concepts are used as the basis for consideration in order to achieve the desired objectives. Keyword: Reconfiguration, Fault Location, Service restoration, Distribution Power System INTRODUCTION The Navy ship electric power system supplies energy to the weapons, communication sys‐ tems, navigation systems, and operation sys‐ tems. The reliability and survivability of a Ship‐ board Power Systems (SPS) are critical to the mission of a ship, especially under battle condi‐ tions. SPS are geographically spread all along the ship. They consist of various components such as generators, cables, switchboards, load centres, circuit breakers, bus transfer switches, fuse and load. The generators in SPS are connected in ring configuration through generator switchboards [1]. Bus tie circuit breakers interconnect the generator switchboards which allow for the transfer of power from one switchboard to another. Load centers and some loads are *Corresponding Author: Tel.: +605‐6909018 Email address: wardiah@mimet.unikl.edu.my supplied from generator switchboards. Load centers in turn supply power to power panels to which different loads are connected. Feed‐ ers then supply power to load centers and power panels. The distribution of loads is ra‐ dial in nature. For vital loads, two sources of power (normal and alternate) are provided from separate sources via automatic bus transfers (ABTs) or manual bus transfers (MBTs). Further, vital loads are isolated from non‐vital loads to accommodate load shed‐ ding during an electrical system causality. Circuit breakers(CBs) and fuses are provided at different locations in order to remove faulted loads, generators or distribution systems from unfaulted portions of the system. These faults could be due to material causalities of individual loads or cables or due to widespread system | MARINE FRONTIER @ UniKL 83
fault due to battle damage. Because of the faults and after isolating the fault, there are unfaulted sections which are left without sup‐ ply. It is required to quickly restore supply to these unfaulted sections of the SPS. This is ac‐ complished by changing the configuration of the system by opening and/or closing some switches (CBsMBTs/ABTs) to restore supply to maximum load in the unfaulted section of SPS to continue the present mission [28]. Shipboard Power System Characteristics Today’s SPS generally use three‐phase power generated and distributed in an ungrounded configuration. The ungrounded systems can keep equipment in continued operations in the event of the single‐phase ground fault. Un‐ grounded systems mean all cabling are insulated from the ship hull. Thus, it optimizes continuity of power (increase equipment reliability). SPS have different characteristics from typical utility power systems in overall configuration and load characteristics. Some of the unique characteristics of the SPSs are as follows: [38] �� There is very little rotational inertia relative to load in SPS. �� SPS are geographically smaller than utility power systems. �� SPS is an isolated system with no power supply from outside power system. �� SPS has a wider frequency range compared to the terrestrial power system. �� Shipboard prime movers typically have shorter time constant than prime movers in �� terrestrial power systems. �� Due to the limited space on shipboard, SPS does not have a transmission system. �� The electric power in SPS is transmitted through short cables. It leads to less power MIMET Technical Bulletin Volume 1 (2) 2010 loss and voltage drop as copared to terrestrial power systems. �� There is a large portion of nonlinear loads rela‐ tive to the power generation capability. �� In SPS, a large number of electric components are tightly coupled in a small space. �� A fault happens in one part of the SPS may af‐ fect other parts of the SPS. �� A large number of electronic loads, such as combat, control and communication �� sensors, radiators, and computers are sensitive to power interruptions and power quality. �� Some electrical components, which affect the reconfiguration process, are unique to SPS such as Automatic Bus Transfers (ABT), Manual Bus Transfers (MBT), Low Voltage Protection de‐ vices (LVPs), and Low Voltage Release devices (LVRs). Due to these unique characteristics of the SPS, some of the mathematical expediencies used in terrestrial power system analysis may not be appli‐ cable to SPS accordingly. For example, infinite buses and slack buses do not have manifestations in SPSs. Constant voltage, constant frequency, and constant power simplifications are usually invalid in SPS. Also, the SPSs are tightly coupled both electri‐ cally and mechanically, requiring integrated model‐ ling of both systems [44]. A brief overview of the loads in the SPS is explained in the following sec‐ tion. Loads in the SPS The loads in the SPS provide various services to the ship. According to the importance of the ser‐ vices being provided, the loads in the SPS can be classified into non‐vital, semi‐vital, and vital‐loads in increasing priority order as follows: Non‐vital (Non‐essential) ‐ Readily sheddable loads that can be immediately secured without | MARINE FRONTIER @ UniKL 84
Page 2 and 3:
EDITORIAL CHIEF EDITOR Prof. Dato
Page 4 and 5:
DIRECTIONAL STABILITY ANALYSIS IN S
Page 6 and 7:
The determinant from equations (3)
Page 8 and 9:
Table 1 ‐ Results of Stability Cr
Page 10 and 11:
DO 20 J=1,7 REFF(J)=1+((J‐1)*1.5/
Page 12 and 13:
Skeg Effectiveness Skeg Effectivene
Page 14 and 15:
Skeg Effectiveness Skeg Effectivene
Page 16 and 17:
A WATER FUELLED ENGINE FOR FUTURE M
Page 18 and 19:
Stainless steel pipes are used as e
Page 20 and 21:
Current development Hydrogen Oceanj
Page 22 and 23:
Car industry A small group of local
Page 24 and 25:
Big oil companies. For business sur
Page 26 and 27:
Websites: 1. http://www.schatzlab.o
Page 28 and 29:
Table 1: Global maritime Fleet Rank
Page 30 and 31:
No. of Ships No. of Ships 300 250 2
Page 32 and 33:
time players is 30. The demand for
Page 34 and 35: References [1] UNCTAD, Review Marit
Page 36 and 37: Table 3 : Tug boat Registered in Ma
Page 38 and 39: NO SHIP NAME OWNER/OPERATOR GRT DWT
Page 42 and 43: MIMET Technical Bulletin Volume 1 (
Page 54 and 55: Table 8 : Tankers Registered in Mal
Page 58 and 59: Table 10: Passenger Ship Registered
Page 62 and 63: Table 11: Container Ships Registere
Page 64 and 65: age and appropriate steps must be t
Page 66 and 67: tends to oxidize rapidly, even at a
Page 68 and 69: oxide or other anti‐oxidant addit
Page 72 and 73: METHODOLOGY Description of Apparatu
Page 74 and 75: Preparation and procedure for Mecha
Page 76 and 77: Objective of the Research The resea
Page 78 and 79: Figure 2.1: LNG Trade Volume 1998,
Page 80 and 81: Mean Median Table 3.1: Carrier Aspe
Page 82 and 83: From the result in Table 3.1, it sh
Page 86 and 87: adversely affecting ship operations
Page 88 and 89: distributed system and other equipm
Page 90 and 91: Knowledge based system is a compute
Page 92 and 93: Again Butler and Sarma [28] put for
Page 94 and 95: particle swarm optimization (PSO)[1
Page 96 and 97: MI [27] Butler, K. L, Sarma, N.D.R.
Page 98 and 99: Positive transformation from its tr
Page 100 and 101: mutually exclusive, but rather comp
Page 102 and 103: Table 2. Measurements for Integrity
Page 104 and 105: Table 5. Measurements for Excellenc
Page 106 and 107: have become a major issue without m
Page 108 and 109: used to model the pneumatic transmi
Page 110 and 111: Figure 2: Transmission Line Diamete
Page 112 and 113: PDE equations (1) and (2). Comparis
Page 116 and 117: Since chemical products have high p
Page 118 and 119: Figure 6: Enclosed life boat with s
Page 120 and 121: UNIKL MIMET AND ALAM SHIP MANAGEMEN
Page 122: MIMET Technical Bulletin Volume 1 (
show all

click here to download - UniKL MIMET Official Website

Create successful ePaper yourself

Delete template?

Save as template?