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© 2005 PRS S.A.
Isolated electric power systems reliability and efficiency improvement based on electric power quality monitoring and control
Project supervisor: Edward SzmitPresenter: Daniel Czarkowski
Polski Rejestr Statków S.A.Electrical and Automation Department
Gdańsk, POLAND
Conference “Aeronautics and surface transport days”11-12 April 2005, Warsaw
2© 2005 PRS S.A.
Ship electric power system
3© 2005 PRS S.A.
Electromagnetic disturbances in a ship’s power network
380
400
420
440
460
U [V]
time [min.]0 41 2 3
Un=11%
59
59.5
60
60.5
61
f [Hz]
time [min.]0 41 2 3
fn=1,6%
4© 2005 PRS S.A.
Voltage distortion
-400
-300
-200
-100
0
100
200
300
400
U [V]
time [s]
THD=4,4%
How to measure power quality?
TotalHarmonicDistortion
-800
-600
-400
-200
0
200
400
600
800
U [V]
time [s]
THD=13,5%
Un=220 V
Un=440 V
5© 2005 PRS S.A.
From deviations to losses
Effects of the occurrence of voltage and current higher harmonics in electric power systems are as follows:
additional power losses in machines, transformers etc., additional power losses In capacitors and coils, dropping accuracy of measuring instruments, occurrence of mechanical vibrations.
What is the reason for calculating THD?
disturbances in power network
perturbs of devices
failurehazard conditions
on a ship
human lives at riskeconomical lossesdanger of pollution
6© 2005 PRS S.A.
Classification societies:
International standard IEC 60092-101:2001 Electrical installations in ships - Part 101: Definitions and general requirements:
– THD ≤ 5%
– voltage deviations -10% +6%
– frequency deviations ±5%
– and other factors
Requirements
PRS LR DNV ABS GL
THD 10% 8% 10% 5% 10%
Different requirements?
7© 2005 PRS S.A.
Results of measurements
type of parameter
THD required by classification
societies
mean THD measured on
a ship
maximum
THD
requirements
/ results5-10% 12-19% 24%
Electronic power converters in power consumer system are often installed on ships, e.g. Queen Mary II.
Ships’ main propulsion systems are more often electric.
Converters cause worse power quality.
Ship technology changes, what about requirements?
© 2005 PRS S.A.
The aim of the project is realisation of ship’s electric power systems based on a choice of appropriate and effective technical solutions as well as on elaboration of algorithms and procedures of proceedings under hazard conditions.
Thank you for your attention
Any further questions please contact me:
[email protected] or project supervisor: [email protected]
