CAISO – Testing and DSOW for New Software Tool Development
GRIDiant entered into a Consulting Agreement with the California Independent System Operator Corporation (CAISO) to demonstrate GRIDfast Optimization Algorithms on Bulk Power System Analysis Examples. GRIDiant performed several “Test Tasks for Optimization Algorithms” authored by CAISO engineers, using WECC and PG&E datasets provided by CAISO. GRIDiant was tasked to develop and demonstrate solutions to specified test problems, including “no feasible solution” cases, a “hard to solve” case, a “constrained optimization problem”, and variations on typical “reliability-must-run (RMR)” cases, with specific tasks directed for each case study. All final GRIDfast solutions were checked by testing them with GE PSLF load flow. Among the GRIDfast capabilities evaluated in GRIDiant’s performance of the Test Tasks were “reliable convergence” and “ability to solve unfeasible power flows (finding the closest feasible point)”. A California ISO delegation of three engineers spent two days in Calgary with GRIDiant GRIDfast staff to test the GRIDfast engine for solving the test cases, and prepared an evaluation of the GRIDfast test results. At the time of the test GRIDfast was at an incomplete stage and the evaluation noted various functionalities that at the time were yet to be completed and therefore unobservable.
On features that were observable, the “Summary of Test Results” included the following:
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California ISO engineers were favorably impressed with the performance of the GRIDfast core solution engine and … in several important aspects (for example, reliable convergence); it was as good as [GRIDiant] had claimed. It does find a feasible solution even when the system is stressed to the limit and beyond. It can solve difficult cases that the PSLF (the GE program used by the California ISO) is not able to solve.”
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“CAISO confirms that GRIDfast has demonstrated excellent performance in at least two hard to crack situations. However, the case used included only the PG&E system (around 3000 buses) and not the whole WECC (approximately 13500 buses). One of them was the case where a branch with a very small impedance was introduced. Typically, power flow algorithms do not converge in such cases due to the difficulties with numerical calculations (the Jacobean matrix becomes ill-conditioned). Nevertheless, GRIDfast was able to find solutions.”
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“Solving unfeasible power flows (finding the closest feasible point): “This test is important to check whether GRIDfast is capable of tracing voltage and angle stability boundaries. GRIDfast has demonstrated an outstanding performance while we attempted to solve a power flow case with no solutions; although we can’t claim that we understand the results completely. To build the case, we scaled one of the bus loads up to the level where no solution could be found. The CAISO PSLF program diverged with the power flow mismatched increasing chaotically. GRIDfast demonstrated an excellent convergence pattern with the mismatches steadily decreasing. This was a clear demonstration of the GRIDfast superiority.”
As a result of its favorable evaluation of GRIDfast through the Test Tasks, CAISO engaged GRIDiant to proceed with creation of a detailed specification for the development of “A New Tool that Three Dimensionally Determines and Enlarges the Secure Operational Region (SOR) in the California ISO Control Area Using GRIDiant Technologies (USA) Inc.’s Advanced Analysis and Optimization Toolset”. In cooperation with CAISO engineers, GRIDiant completed the detailed specification for the 3-D SOR.