ERCOT Grid Contingency Analysis

Classify which investment-screening conclusions a steady-state study can support and which require formal ERCOT interconnection studies.

Inspect an ERCOT case for study year, season, dispatch, topology, and revision metadata.

Open and solve a working copy of an ERCOT base case in PSS®E 35 using appropriate steady-state solution controls.

Diagnose common causes of a base case that does not solve or does not match its saved solved state.

Create a case-provenance record documenting data sources, software version, case modifications, and study assumptions.

Interpret PSS®E bus, branch, transformer, generator, load, area, zone, and owner records used in contingency analysis.

Distinguish PSS®E area, zone, owner, and subsystem labels from electrical interfaces and GIS regions.

Trace the electrical connection between a candidate point of interconnection and the surrounding transmission network.

Calculate an interface transfer from constituent branch flows and reconcile it with area interchange, tie-line flows, and slack-bus response.

Define source and sink subsystems for a transfer between areas or regions.

Choose and document a balancing method for incremental generation, load, or BESS operation.

Account for incremental system losses when measuring a transfer.

Use transfer distribution factors to prioritize facilities for detailed AC monitoring without treating those factors as substitutes for AC analysis.

Locate and record the revision dates of current ERCOT documents governing steady-state planning events and performance criteria.

Translate applicable ERCOT event categories into explicit PSS®E outage definitions.

Translate applicable thermal criteria into normal and emergency rating checks.

Translate applicable voltage criteria into pre-contingency and post-contingency checks.

Determine which operator actions or system adjustments are permissible for each studied event.

Define rules for separating pre-existing problems from project-caused or project-worsened violations.

Construct a study matrix covering facility type, operating mode, case, transfer direction, balancing assumption, and contingency class.

Explain the distinct roles of `.sub`, `.mon`, `.con`, and `.dfx` files in PSS®E contingency analysis.

Write a subsystem definition that selects the intended source, sink, and study regions.

Choose a monitored network scope that captures credible local and inter-area impacts without monitoring the entire model unnecessarily.

Write a monitor file containing the required branch, transformer, interface, and bus-voltage checks.

Write single-element contingencies for transmission lines, transformers, generators, and shunts.

Represent credible multi-element and common-mode outages without accidentally creating unrelated N-2 combinations.

Compile a distribution-factor file and resolve subsystem, monitor, and contingency compilation errors.

Audit subsystem, monitor, and contingency coverage for missing, duplicate, incorrectly identified, or out-of-service equipment.

Configure an AC contingency-analysis run with documented solution controls, rating selections, and convergence settings.

Evaluate intact-case thermal and voltage conditions against the applicable N-0 criteria before applying contingencies.

Run a baseline ACCC study in PSS®E and preserve its inputs, progress log, and output files.

Extract and tabulate each violation's contingency, monitored element, rating, loading, voltage, and applicable limit.

Classify contingency outcomes as solved, islanded, diverged, or otherwise invalid.

Diagnose false violations caused by ratings, statuses, duplicate circuits, metering ends, monitoring definitions, or model defects.

Validate a severe ACCC result by reproducing the outage in an interactive AC power-flow case.

Calculate the remaining thermal or voltage margin for a limiting contingency.

Define a machine-readable run manifest containing cases, scenarios, transfers, contingencies, thresholds, and output locations.

Specify the required PSS®E automation sequence from case loading through result export.

Define stable identifiers that prevent buses, circuits, transformers, scenarios, and contingencies from being confused.

Specify logging and exception handling for non-convergence, islanding, missing equipment, malformed inputs, and incomplete outputs.

Define acceptance tests that compare an automated run with a manually verified PSS®E run.

Review LLM-generated PSS®E automation for hidden assumptions, unsafe defaults, unintended case mutations, and incomplete error handling.

Document PSS®E 34 and 35 environment differences that affect script execution and reproducibility.

Build a steady-state screening model for a proposed generator at a candidate point of interconnection, including any study-equivalent GSU, interconnection transformer, or generator-tie branch required by the chosen abstraction.

Set generator voltage-control, reactive-limit, and power-factor assumptions for a screening scenario.

Represent incremental load at a candidate bus or group of buses using explicit MW, Mvar, power-factor, and static load-model assumptions.

Represent BESS charging and discharging as separate steady-state snapshots while documenting the state-of-charge and energy-duration questions that steady-state analysis cannot answer.

Define deterministic pass/fail rules covering N-0 and N-1 limits, pre-existing violations, project-caused changes, convergence, islanding, and numerical tolerances.

Execute a stepwise transfer search to establish a passing and failing bracket for hosting capacity.

Refine a monotonic pass/fail bracket with bisection to a stated MW tolerance and revert to bounded stepping when monotonicity is not demonstrated.

Identify the contingency and monitored facility that bind the reported hosting-capacity limit and calculate the associated headroom.

Distinguish simultaneous N-2 analysis from sequential N-1-1 analysis and ordinary N-1 screening.

Select credible outage pairs using topology, common-mode exposure, prior N-1 severity, and applicable criteria.

Estimate the computational growth caused by expanding an N-1 list into outage pairs.

Create a controlled set of multi-element contingencies for selected simultaneous N-2 events.

Model the sequence and permitted intermediate corrective actions for a selected N-1-1 event.

Separate credible limiting results from outages that island load or generation by construction or otherwise fall outside the study criteria.

Report N-2 and N-1-1 results separately from the core N-1 hosting-capacity estimate.

Select future-year, seasonal, and load-level cases relevant to a proposed ERCOT investment.

Define dispatch and balancing sensitivities for nearby conventional generation, renewables, storage, and incremental transfers.

Define topology and planned-outage sensitivities that could materially alter transfer capability.

Run a consistent hosting-capacity study matrix across multiple cases and sensitivities.

Calculate a capacity range from scenario-specific limiting results rather than reporting only one MW value.

Identify assumptions that dominate the uncertainty in a candidate point-of-interconnection result.

Assign a documented confidence tier to a screening result based on case coverage, model quality, and result stability.

Compare candidate locations using capacity, constraint severity, uncertainty, confidence, and data-quality indicators.

Use flow changes and network topology to explain why a particular facility limits a proposed injection or withdrawal.

Screen whether redispatch or renewable curtailment relieves a limiting contingency.

Screen a documented line or transformer uprate assumption without treating an unsupported rating edit as evidence of an available upgrade.

Screen whether a conceptual transmission reinforcement materially increases the passing transfer.

Screen whether voltage-control or reactive-support changes relieve a voltage-limited result.

Quantify the incremental MW benefit of a candidate mitigation by rerunning the same study matrix.

Classify an apparent upgrade need as not indicated, sensitivity-dependent, or consistently indicated by the available screening evidence.

Define stable GIS join keys that connect PSS®E equipment records to authoritative spatial assets.

Design separate tables for study runs, scenarios, contingencies, monitored assets, violations, and hosting-capacity summaries.

Define fields for base values, post-contingency values, limits, margins, transfer levels, quality flags, and result status.

Represent buses and candidates as points and lines and transformers with authoritative geometries while keeping scenario and constraint relationships in normalized attribute tables.

Export normalized contingency results to validated CSV and Excel files.

Export candidate sites and constrained network assets to valid GeoJSON with documented coordinate provenance rather than using PSS®E diagram coordinates as geographic coordinates.

Specify GIS layers, filters, labels, and symbology for capacity, severity, scenario, confidence, and data quality.

Validate row counts, identifiers, units, coordinates, null handling, uniqueness, and referential integrity before GIS handoff.

Write a study specification for one generation, load, or BESS candidate using explicit cases, criteria, and assumptions.

Build the subsystem, monitor, and contingency inputs for the selected candidate study.

Produce a manually verified baseline result against which automation can be tested.

Prepare an implementation brief and acceptance tests for generating the required PSS®E automation with an external coding assistant.

Determine N-1 hosting capacity for the applicable injection and/or withdrawal directions across the selected scenarios.

Perform a selective N-2 or N-1-1 sensitivity on the candidate's most consequential constraints.

Assemble an auditable results package containing assumptions, quality checks, capacity ranges, limiting constraints, confidence indicators, and GIS-ready exports.

State the investment conclusions supported by the screening and identify the additional studies required before a commitment or interconnection decision.