Power Quality Management in Electric Ships
If you are an electric ship owner or operator, you should know how to implement power quality management on board your vessel. This will ensure that you can operate your ship in the most efficient and safe way possible. Power quality management aims to reduce harmonics, waveform distortions and other issues that can cause your vessel to break down. These will help you avoid costly repair bills and will also keep your vessel operational for a longer period of time.
Electric power quality assessment should be a priority in ship use. For ships with electric propulsion, a new requirement has been introduced by IACS (International Association of Classification Societies). It requires the monitoring of harmonic voltage distortion levels in the electrical power system.
Harmonics are produced by power converters and electronic devices. These effects affect the load, the power network and the entire power system. In addition, they can cause excessive errors in meters based on peak values. The effects of these disturbances can be very serious and may require a more complex solution.
Electrical power solutions are gaining popularity in marine propulsion systems. These solutions offer superior operational characteristics. They also have flexibility for machine room layout.
A number of studies and tests have been conducted. Results show that harmonic effects can be significant in marine propulsion systems. However, the maximum allowed values of individual harmonic components are not known.
Limiting harmonics to 50th order
If your ship is all electric, you should be aware that harmonics can affect the performance and safety of your electrical equipment. The authors of this report provide information on how to mitigate the effects of harmonics on the electrical systems of ships. They also propose solutions to indices of distortion and transient disturbances.
Harmonics are caused by the generation of electrical power at the distribution level. They can be modelled by a Fourier series. In order to make sure that the generators of your power system are generating the correct amount of voltage and current, you will need to set limits for the magnitude of harmonics.
To do this, you will need to calculate the total harmonic distortion. This is also known as the total demand distortion. While this is not an absolute measurement, it is a good start. For example, if you have a 400 V busbar, it is safe to assume that you can tolerate THD of at least 10%.
Impact of changes in IMO instruments on power quality management
In recent years the importance of power quality in maritime power systems has increased. This is partly due to the introduction of new types of energy production, but it is also because of the peculiarities of maritime power systems.
A number of measures have been implemented to improve the efficiency of ships. These range from design modifications to changes in operational practice. The aim of the measures is to decrease the energy efficiency gap between present and future. However, implementing these measures is not always straightforward.
One problem is the lack of a normative metric to measure overall efficiency of the fleet. This makes it difficult to evaluate the effectiveness of ship modifications.
There are also uncertainties associated with the introduction of renewable energy. These can make the operation of multi-energy shipboard microgrids complicated. Besides, these can complicate the coordination between seaports and ships.
Despite the difficulties in introducing these measures, some improvements are already underway. For example, some systems are able to detect and reduce power quality disturbances.
Examples of power quality problems on ships
Electric power quality assessment and improvement remain one of the most important issues in ship systems. It is a complex issue requiring continuous monitoring. Currently, there are several methods available for solving the problem. They include technological solutions, such as harmonic filters cooperating with shaft generators and super capacitors. In addition, there are also passive control solutions, such as appropriate configuration of the main switchboard.
Despite the progress in technology, ship accidents still happen, even with high-technology ships. However, they can have serious consequences. Depending on the magnitude of the accident, they can be fatal.
To reduce the risks of accidents, it is necessary to implement power quality improvement. These improvements can be achieved through the use of correct technological solutions and staff competencies. The author believes that these methods should be implemented onboard and in the ship’s service.
Power quality disturbances can be harmful to ships and the crew members. Therefore, they should be evaluated from the point of view of reducing the risk of ship accidents.