ONR Electric Ship

Approaches to Shipboard Power Management

Shipboard power grid reconfiguration is a key ingredient for survivability, under adverse conditions, and for efficient grid operation. Two requirements surface if the procedure is to be implemented close to real time. First, the complicated dynamics of the system must be accurately modeled by a simpler equivalent model. Second, a constrained optimization problem has to be solved very rapidly. The second objective’s challenge grows exponentially with the number of possible switch states. Both discrete integer optimization techniques and stochastic algorithms have been successfully examined in this regard. A new and promising technique involves partial variable solutions; a subset of the solution space is treated as known and the global solution approached iteratively. The technique shows a 60:1 speed up in solution on the test grid in Fig. 1 which has16 million possible configurations.

Interconnected Mesh Grid Represented with Equivailent Impedances

Among the most promising uses of this technology is in future planning. Fig. 2 shows the demands for current carrying capability if the trunk lines are sequentially taken out of service. The reconfiguration algorithm determines the required current rating on every line to insure full performance in this scenario. The loads highlighted have minimum power delivery requirements specified throughout the exercise. In this manner, reconfiguration should help the Navy plan the conductor size throughout their grid a priori.

Current on every trunk line necessary to insure full functionality with the loss of any one line

For more information about this, please contact Kent Davey.

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