Chronological AC Power Flow Cases From PCM Grid Simulations
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Solution Overview
Problem
Existing power grid analysis tools are insufficient for generating detailed operational impact assessments due to the reliance on a limited number of base power-flow cases, particularly in systems with high renewable penetration, and there is a lack of effective methods to seamlessly translate production cost models (PCM) into AC power flow models (PFM) for large interconnected systems.
Innovation Solution
A computer-implemented method that extends PCM simulation results to an AC power flow model by iteratively updating inputs and performing numerical analyses to achieve convergence, incorporating generation and load distribution mappings, and utilizing reactive power planning to address voltage violations, thereby producing a chronological series of AC PFM solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a limited number of base power-flow cases are used for planning, then the analysis complexity is reduced, but the ability to capture operational impacts like voltage stability is insufficient
Solution Approach 1:
The patent segments the power system into multiple balancing authorities (BAs) and creates numerous chronological power-flow cases by varying generation and load scenarios within each BA. This segmentation allows comprehensive operational impact assessment without requiring analysis of the entire system at once, thus maintaining manageable complexity while improving reliability of impact assessment.
Solution Approach 2:
The patent transitions from static base power-flow cases to dynamic chronological power-flow cases that capture time-varying operational conditions. By dynamically adjusting generation and load scenarios across multiple time steps, the system comprehensively assesses operational impacts including voltage stability while maintaining analytical tractability through structured scenario management.
2Ease of manufacture
If DC production cost model results are directly used without translation, then the modeling process is simpler, but the results cannot be successfully fed to AC power flow models
Solution Approach 1:
The patent introduces an intermediary translation process that converts DC production cost model results into AC power flow model inputs. This intermediary layer includes mapping generation and load data between models, adjusting for losses, and reconciling different modeling assumptions, thereby enabling successful integration while maintaining relative simplicity of the overall process.
Solution Approach 2:
The patent systematically changes key parameters when translating between DC and AC models, including adjusting for transmission losses, converting generation and load representations, and adapting voltage and power flow parameters. These parameter transformations enable compatibility between the simpler DC model and the more detailed AC model while preserving the essential characteristics of the production cost optimization results.
3Productivity
If transmission losses are not accounted for in the power flow model, then the computational process is faster, but the accuracy of power flow solutions is compromised
Solution Approach 1:
The patent performs preliminary loss calculations based on DC model results and uses these to pre-adjust generation and load values before running AC power flow analysis. This preliminary action accounts for transmission losses in advance, allowing the AC power flow solver to converge more quickly while maintaining accuracy, thus preserving both computational speed and solution precision.
4Loss of time
If voltage violations are not addressed, then the analysis process is shorter, but the system reliability assessment is insufficient
Solution Approach 1:
The patent implements a feedback mechanism where AC power flow solutions are checked for voltage violations, and if violations are detected, the system automatically adjusts generation and load scenarios and re-runs the analysis. This feedback loop ensures comprehensive reliability assessment by identifying and addressing voltage issues while maintaining reasonable analysis time through targeted re-analysis only when violations occur.
Data Source
AI summary
A computer-implemented method includes extending simulation results and input data of a DC production cost model (PCM) of a power grid to an initial AC power flow model (PFM) using a generation distribution mapping and load distribution mapping of a related PFM base example associated with the PCM, and automatically producing a chronological series of converged AC PFM solutions associated with a PCM time series by, for each time step of the PCM time series: (i) updating inputs of an AC PFM using (a) PCM results of the current time step and (b) solution outputs of a converged AC PFM obtained from a previous PCM time step, and (ii) iteratively, reducing nodal loads by a gradual amount configured to account for power grid power flow losses unaccounted for by the PCM and performing AC PFM numerical analyses, until: (a) an AC PFM convergence is obtained and (b) a real power generation slack bus is less than or equal to a predefined tolerance in relation to a slack bus of the PCM results of the current time step.