DC breaker’s spinning reserve mode

Spinning reserve as a safeguard in case of a generator failure

Spinning reserve refers to the operating state of power generation equipment that is running at a low load or idle, ready to quickly supply power to meet sudden increases in demand or compensate for a loss of other power sources. Spinning reserves are critical for maintaining the stability of marine electrical systems. Our DC breaker’s spinning reserve mode helps the system as a safeguard when a generator is failing, and the energy storage system functions as an emergency power source. During this time, the spinning reserve mode is active, which gives time to start up a backup generator.

Activating spinning reserve mode

The DC breaker’s spinning reserve mode is enabled when a grid failure occurs, and the energy storage system is used as a backup generator for a predefined time.

The situation in short. During a generator failure and enabled spinning reserve, the energy storage system compensates this loss of power for a limited time, until the backup generator is online. The time limitation for this specific mode will not exceed 30 minutes with a 20% overload. Due to this prolonged overload situation, it is in most cases considered a power rating.

The spinning reserve mode function of our solid-state DC breaker allows a 20% overload in power for 30 minutes.

The advantages of the spinning reserve mode in our solid-state DC Breaker

Typically, an overload will take less than one minute, and most devices can withstand these short overload situations. However, accepting an overload of 30 minutes is a unique feature.

By adding the spinning reserve mode functionality to our DC breaker and accepting the 30 minutes overload, it gives the system integrator the opportunity to select a smaller solid-state DC breaker, which will save costs and space.

Mitigating the risk of a complete system blackout

When a generator failure occurs in a DC power grid without backup system, the affected part of the DC grid must be isolated. A system design with an energy storage system that can function as a backup power source is therefore preferred and could be considered as an UPS (Un-interruptible Power Supply).

By using the Energy storage system in spinning reserve mode, the battery system will be strained in such a way that battery manufacturer limits this feature to a maximum of 12 occurrences a year. Although our solid-state DC breakers can withstand even more, the limitation in our new DNV marine product type approval certificate, matches the restrictions of leading battery manufacturers. In other words, the restriction of 12 times a year, 30 minutes and 20% overload is not a restriction of the Astrol solid-state DC breaker.

Our range of 1.5 kV solid-state DC Breakers

Implementation

To enable the spinning reserve mode, the time parameter of the already existing I2t overload protection will be extended from the original 100 seconds to 30 minutes. This change doesn’t require any new feature implementations but is accomplished by changing configurable system parameters only. The operator has the option to enable or disable spinning reserve mode.

Why choose our solid-state DC Breaker with spinning reserve mode?

1. Using a DC breaker with the same rating in an overload situation
2. Marine type approved solutions (DNV, Lloyd Register, CCS)
3. Safe and reliable solution
4. Easy integration into existing systems
5. Increase system up-time