~ The role of resistors in the supply of icebreakers ships ~
Sea ice covers about twelve percent of the world’s oceans, blocking the path of ships trying to travel through the coldest regions of the Earth. Although not a new concept, icebreakers are constantly playing a crucial role in clearing these routes for trade, research projects and travel. Here is David Atkins, Project Director at marine resistor manufacturer Cressall, delves into the nuances of the design of electrical components for icebreakers.
Icebreakers are a special class of vessels designed to break through even the thickest ice sheets. Originally designed to open trade routes that experience seasonal or permanent ice conditions, icebreakers are typically located in areas such as the Barents Sea, the Arctic Ocean and the St. Lawrence Seaway. More recently, they have also been used to support research projects in the Arctic and Antarctic.
To meet the challenges of ice-covered waters, icebreakers have a very specific, carefully thought-out design. The icebreaker’s nose has a unique shape that is smoother and rounder than a standard vessel to allow it to glide easily on thick ice sheets with minimal counter-force. As it glides on the ice in this way, the weight of the ship drops on the ice, crushing it and clearing the way.
To power the icebreakers to move smoothly over this difficult seascape, ships also require a significantly improved electric propulsion system that meets the power requirements for the icebreaker’s thrusters to break the ice.
As the only tool for transporting through these ice-covered waters, it is essential that the propulsion system – and all the components it includes – are reliable, efficient and protected. If an icebreaker is damaged during transportation, there may be serious disruptions in the global supply chain during repairs. Think of the Suez Canal fiasco in 2021, but much colder.
One component that plays a crucial role in ensuring the safe operation of the electric drive system of the icebreaker is dynamic braking resistor (DBR). When there is no ice in the ship’s path, there is less load on the system, which means that any excess energy produced is a surplus of needs. To dissipate this excess energy, a DBR is integrated into the system, which acts as an unloader during propulsion and ice breaking. This load discharge activity stabilizes the energy system, ensuring a constant load on the ship’s gas engines.
It is important to include DBR in an electric icebreaker propulsion system for several reasons. Without DBR, the power system would be destabilized, risking potential damage to other components of the power supply circuit. If this continues, it could eventually lead to the loss of the ship’s ice-breaking function and the complete failure of the energy system.
Therefore, the integration of DBR is absolutely necessary for engineers designing icebreakers. However, this is not as simple as simply choosing a DBR. There are several design elements for this specific application that must be taken into account to ensure optimum drive performance.
When designing electrical components, such as resistors, for the use of icebreakers, several application-specific factors must be taken into account. Each component must be able to withstand the salty, cold and unstable conditions that are common at sea.
In terms of structural stability, rigorous finite element analysis (FEA) testing procedures provide evidence of a component’s ability to withstand unpredictable, inhospitable conditions. It is also important to design in accordance with the standards set by Bureau Veritas’ global testing, inspection and certification specialists for global compliance.
The salty atmosphere in the sea is corrosive, so choosing the right material is essential to prevent equipment from running out of salty seawater. For metal components, it is important to use stainless steel with a chromium content of at least 10.5 percent. This allows the stainless steel to react with oxygen to create a protective layer that prevents corrosion, even when unpainted.
Icebreakers are an integral part of the maritime transport system. Although their function is simple, having the right electrical components, including DBRs designed specifically for ice-breaking applications, is crucial to their safe and successful operation, making even the most insidious routes in the polar regions available year-round.
Cressall designs and manufactures DBR specifically for icebreakers. Our team of expert engineers works with our customers to develop the ideal DBR solution for the customer for each application. For more information, please contact here.
The publication Ice Breaking @CressallR #engineering #engineeringupdate first appeared in the Engineering Update.