Difference between revisions of "GridPACK Release Notes"

Revision as of 22:18, 3 October 2014

GridPACK v2.0

This release of GridPACK™ contains several new features and a new example application, as well as multiple bug fixes and performance enhancements. It also contains a new Fortran 2003 interface that allows users access to almost all the GridPACK™ functionality. The new power grid application is a state estimation code that can be used to find optimal values of the voltage magnitude and phase angle based on measurements of the power grid system. To implement this calculation, several new features were added to the GridPACK™ framework. These include a more general mapping capability for constructing the matrices used in solving power grid problems and a data distribution module that automatically distributes data to the processes containing the buses and branches that need the data.

The existing mapper functionality supports systems where variables and equations are associated with the buses. This is the case for systems such as powerflow and dynamic simulation. With state estimation, equations are associated with measurements that occur on the branches and a new model for mapping elements from the network to matrices and vectors is required. This has been implemented in Version 2.0 and is available through new generalized mapping modules.

Many power grid applications have large amounts of data that map to individual buses and branches but are not included in the original network configuration file. Mapping this data to a distributed network can be a major challenge. The hash distribution module can be used to redistribute data that has been read in on either a single processor or a collection of processors to the processor that owns the bus or branch objects that requires the data. The user interface for this module contains only a few simple commands but it can eliminate a large amount of complicated data exchanges.

GridPACK v1.1

This release of GridPACK™ contains several new features as well as multiple bug fixes and performance enhancements. Two new applications, illustrating the use of GridPACK components in building power grid simulation codes, are included as well as some additional codes that serve as pedagogical examples of how to use basic GridPACK functionality. The power grid applications include a contingency analysis code that can run multiple instances of the power flow simulation with individual transmission elements or generators eliminated from the calculation and a dynamic simulation code that can be used to evaluate the behavior of a temporary fault in one of the transmission elements.

Two example codes have also been included in this distribution that illustrate some of the features of the GridPACK™ framework without requiring users to master the complexities of a working power grid application. The first is a simple “hello world” code that shows how to create a simple network, initialize buses and branches on the network and use the IO modules to print a message from each bus and branch. The second example is a resistor grid application that solves a simple electric circuit problem for a network of electrical resistors. A current is induced in the system by holding two buses at different voltages. The code solves the corresponding linear electric circuit problem and prints out the potentials on all buses and the currents on all branches. This code adds a few elements beyond the “hello world” problem by showing how to create matrices based on properties of the grid and showing how to create a linear solver.

Besides including new applications and example codes, this release also includes improved communicators that can be used to implement multiple levels of parallelism in applications and a new task manager that can be used to distributed tasks on a first come, first serve basis. The task manager can be combined with the new communicators to implement dynamic load balancing calculations with relatively little effort. Several important bugs and performance issues have also been addressed in this release. The most important relates to how matrices are distributed internally. This bug was causing crashes in matrix-matrix and matrix-vector multiplies due to mismatched data distributions. Removing this bug has resulted in much more robust code for performing algebraic operations. Another significant performance bug has been the partitioner, which has been extremely slow for very large network configurations. Recent improvements have resulted in substantially better performance and reliability. However, issues remain for very large networks on many processors and the partitioning software remains an area of active development.

GridPACK v1.0.2

• Improved performance of partitioning software significantly and fixed some bugs that were causing hangs on some workstations

GridPACK v1.0.1

• Fixed parser so that powerflow application can run large WECC calculation

GridPACK v1.0

• Original GridPACK release