Interconnection Command Center
A working guide to Transmission & Distribution interconnection engineering and the program management discipline that carries a project through it — the five technical studies that determine grid impact, the FERC Order 2023 process that governs the timeline, who owns what along the way, and how a real application actually moves from Day 0 to energization.
A grid absorbing more interconnection requests than it was built to process
Every generator, battery, or large load that wants to connect to the grid has to prove — with simulation, not intuition — that it won't overload equipment, collapse voltage, destabilize neighboring generators, or interact badly with its own power electronics. That proof is the five studies below. What changed in 2023 is the process wrapped around them: FERC Order No. 2023 replaced a first-come-first-served queue that had backlogged over 10,000 projects nationwide with a cluster-study model built on firm deadlines, tiered financial penalties, and shared cost allocation. The engineering hasn't gotten simpler — inverter-based resources alone have added a whole new study category, most of it run in PSCAD/EMTDC, the electromagnetic transient platform that has become the de facto proof standard for ride-through and control-interaction behavior — but the program management discipline required to carry a project through it, on schedule and without unnecessary financial exposure, now matters as much as the engineering itself.
The old serial queue vs. the FERC Order 2023 cluster process
Order No. 2023 (effective 2023, with clarifications in Order No. 2023-A) didn't touch the five studies themselves — it rebuilt the process, deposits, and accountability wrapped around them. This is the shift every PM on a live interconnection needs to reason from.
| Dimension | Old Process (pre-2023) | FERC Order 2023 |
|---|---|---|
| Queue methodology | Serial, first-come-first-served — one request studied at a time, in queue order | Cluster-based — every request in a fixed window studied together |
| Study structure | Three sequential phases — Feasibility, System Impact, Facilities — each its own deposit and restart point | Single-phase Cluster Study merges Feasibility + SIS; Facilities Study remains separate |
| Timeline accountability | "Reasonable efforts" standard — no enforceable deadline, no penalty for a late study | Firm ~150-calendar-day cluster study clock, with FERC-mandated penalties payable to the customer for missed deadlines |
| Financial deposits | Separate deposit due at each of the three study stages | Single MW-based study deposit; LGIA deposit = 20% of Network Upgrade estimate (replaces the old 9x-study-deposit formula) |
| Site control | Requirements varied by tariff and were inconsistently enforced | Explicit thresholds — 90% at request submission, 100% at Facilities Study Agreement execution |
| Cost allocation | First-studied projects could be assigned upgrade costs that later, lower-queued projects also benefited from — a frequent dispute source | Proportional-impact methodology allocates Network Upgrade costs across the whole cluster |
| Withdrawal penalties | Often minimal — a weak deterrent that let speculative "phantom" projects clog the queue for years | Tiered — pre-restudy penalty based on accumulated study costs; post-restudy penalty based on the Network Upgrade cost increase |
| EMT / IBR screening | Ad hoc — required inconsistently, often bolted on late when control-interaction issues surfaced | Increasingly built into the Cluster Study itself for IBR-heavy requests, via PSCAD/EMTDC ride-through and stability screening |
Figures are as reported by FERC and industry counsel at the time Order No. 2023 was issued; consult current ISO/RTO tariffs for the process actually governing a live project.
What each study simulates, and why it's on the critical path
A plain-language pass before the technical detail in the Studies Archive — what each model is, why it's performed, and where it actually matters in a live project.
Steady-State Power Flow
General info — Phasor-domain simulation of bus voltages and MW/MVAr flows under specified dispatch and load conditions.
Importance — The baseline screen that catches most interconnection-blocking issues first; a project that fails here rarely proceeds without significant network upgrades.
Use & relevance — Run first in every Cluster Study and re-run as the network model is refined; its results directly drive the Network Upgrade cost estimate that shapes every later decision gate.
Short-Circuit (Fault Duty)
General info — Sequence-network fault analysis quantifying prospective fault current at buses of interest for each major fault type.
Importance — Protects people and equipment — undersized switchgear is a safety issue, not just a compliance one, which is why utilities lean on this study hardest.
Use & relevance — Performed alongside power flow in the Cluster Study, then revisited in the Facilities Study; its outputs size breaker replacements that are frequently on the critical path.
Transient & Dynamic Stability
General info — Electromechanical time-domain simulation of how generators and IBRs respond to large disturbances, establishing Critical Clearing Time margins.
Importance — Where one project's behavior can threaten wide-area reliability, not just its own interconnection — the study most likely to trigger NERC TPL/PRC-driven mitigation.
Use & relevance — Essential wherever IBRs are a large share of local generation; results shape ride-through and control settings written directly into the Interconnection Agreement.
EMT Modeling
General info — Sub-millisecond PSCAD/EMTDC simulation capturing control-system-level behavior that phasor-domain tools cannot see.
Importance — Weak-grid, IBR-heavy interconnections have caused real control instability that only EMT analysis catches before energization — the fastest-growing study requirement industry-wide.
Use & relevance — Triggered above SCR/IBR-share thresholds; typically the longest-lead study due to OEM model/NDA turnaround, and often the true critical path of the whole timeline.
Affected System & Distribution Screening
General info — Extends the same impact analysis across a system boundary — to a neighboring transmission owner, or down to the distribution feeder.
Importance — Without it, a project can pass every test on its own host system and still be blocked on a system it doesn't control — a common source of late-stage surprise cost.
Use & relevance — Runs on its own ~150-day track for transmission projects; for DER/distribution projects it's often the entire study, via hosting-capacity screening.
Six modules, one project lifecycle
Studies Archive
The five models above, expanded into full technical detail — inputs, failure criteria, and mitigations.
PM Tracker
Six FERC Order 2023 phases — milestones, deliverables, risks, and financial security at each stage.
RACI Matrix
Who owns what across Customer, TO, RTO/ISO, and Consultant/EPC — filterable, with each handoff explained.
Pipeline Simulator
Walk an application from Day 0 to COD — toggle project type, data-validation outcome, and both withdrawal gates to see timeline and cost respond live.
Tools & Software
Every platform named in this guide, grouped by discipline — PSCAD, PSS/E, ASPEN, and the ISO queue portals — with what each is for.
Study Eng. Services
The seven client-facing service lines that package the studies and PM process above into deliverable engagements.