What is Efficient Unit Dispatch?

Efficient Unit Dispatch is a technology that can optimize the allocation of production across numerous available hydro-generation units. The technology allocates production so as to minimize the overall cost of production (water usage) while meeting production targets. Traditionally the allocation process is left to operators with experience or it is split evenly across the operating units. This method often results in a significant cost due to units running sub-optimally. This cost is often found to be over 1% of total production, and equate to many hundreds of thousands of dollars per site per annum.

The optimization of hydropower systems requires a complex mathematical solution. The complexity is due to the many non-linear mathematical relationships that are related throughout the power generation system.

For example the power generated on a turbine is product of the net head and the unit discharge flow. Each Unit has a unique efficiency curve that relates the power generated on the unit to the flow of water used. The stations efficiency is a function of each unit's efficiency, while the fast and slow reserve are related to the unit dispatch.

How does it work?

In order to compute the most effective allocation method, Efficient Unit Dispatch technology must automatically link into a control system or data source that possesses real time process information. The system must use this information in conjunction with models of individual unit performance and other constraints to determine the best allocation of production. The Efficient Unit Dispatch system is a software product that:

• Connects to real time data sources, OPC servers, PLC's and data historians such as the PI System.

• Gathers input data on a real time basis e.g. seconds

• Stores an accurate data model about production, including Turbines, Stations, and the Schemes.

• Performs real-time analysis of unit performance.

• Calculates the most efficient method of operating the units to meet production targets while observing any production constraints.

• Provides advisory information, decision support tools, and graphics to production operators in real time.

• Provides summary performance information to managers.

Why is this difficult?

The Efficient Dispatch technology from Bravure solves a number of difficult technical issues with one easy to install packaged software solution. Some of the challenges include:

• In a typical optimization there are literally billions of billions of potential solutions to any dispatch problem. Despite this, the Optimisation software can compute an optimal solution within milli-seconds. The graphic to the right provides a visualization of a three dimensional map of the many potential solutions to a dispatch problem. If each peak represents a case of high overall water flow, then the objective is to find the lowest valley on this three dimensional map, thus minimizing the total water consumed across the site.

• Accurate models need to be generated for all significant relationships to properly optimize a hydro system. Any simplification of relationships with linear modeling leads to inaccurate results and a resulting poor station performance. Smooth, continuously differentiable, and continuously interpolable non linear curves are therefore used to characterize unit performance.

• There are many technical challenges associated with connecting to proprietary real time data sources such as PLC's and data historians. In addition there are challenges associated with publishing real time updates to client software across different data networks through firewalls.