Generation Injection & Large Load Withdrawal

Executive Summary

Connecting a new generation facility or large industrial load to the transmission grid is one of the most technically complex, commercially consequential, and time-sensitive activities in the energy sector. Whether the project involves a power plant seeking to inject energy into the grid or a large industrial facility requiring substantial load withdrawal — such as a steel plant, data center, or manufacturing complex — the interconnection process demands deep technical expertise, precise engineering analysis, and thorough knowledge of utility and ISO procedures.

This white paper provides a technical overview of the generation injection and load withdrawal interconnection study process, explains the key analytical disciplines involved, and describes how Keentel Engineering's specialized services guide developers, industrials, and utilities through every phase — from initial Point of Interconnection (POI) screening to final application submission.

  Keentel Engineering's interconnection study services are designed to deliver one clear outcome: identify the best available Point of Interconnection for the client's asset, prepare all required technical models and documentation, and support a successful interconnection application — faster and more cost-effectively than conventional approaches.

1.  Understanding Transmission Interconnection

1.1  What Is a Transmission Interconnection?

A transmission interconnection is the physical and contractual connection of a new facility — either a generation source or a large load — to the high-voltage transmission network. This connection allows the facility to exchange power with the broader grid: generators inject power into the network for delivery to consumers, while large loads withdraw power from the network to meet their operational demand.

Unlike distribution-level connections, transmission interconnections involve high-voltage infrastructure (typically 69 kV and above), complex power flow interactions with the broader regional network, and formal regulatory processes administered by Independent System Operators (ISOs), Regional Transmission Organizations (RTOs), and Transmission Owners (TOs). The interconnection process is governed by FERC regulations, NERC reliability standards, and the specific tariffs and procedures of the applicable utility or ISO.

1.2  Generation Injection vs. Load Withdrawal — Key Differences

While both generation injection and load withdrawal interconnections share many common study requirements, they present distinct technical challenges that must be addressed through specialized analysis:

1.3  The Co-Located Facility Challenge

Projects involving both a large generation facility and a large industrial load at the same site — such as a power plant co-located with a steel plant or industrial complex — present a uniquely complex interconnection scenario. The combined injection and withdrawal must be studied simultaneously to understand:



• Net import and net export operating conditions across all combinations of generation output and load demand
• The facility's aggregate impact on the transmission network under all operating modes
• Whether a hybrid interconnection application or separate applications for each facility is the more efficient approach
• How the generation injection offsets or exacerbates the load withdrawal impacts on the network

Keentel Engineering specializes in this combined facility interconnection scenario, having developed structured analytical workflows that address the full complexity of simultaneous injection and withdrawal studies within a single, integrated study framework.

2.  The Transmission Interconnection Process

2.1  Overview of the Process



The interconnection process follows a structured sequence of activities — from initial site and POI assessment through formal application, utility study, and ultimately Interconnection Agreement execution. Understanding this process is essential for developers and industrials to plan their project timelines and budgets effectively.

3.  Keentel Engineering's Interconnection Study Services

Keentel Engineering provides end-to-end client-side interconnection study services across six core technical disciplines. Each discipline addresses a specific aspect of the interconnection analysis required to select the optimal POI, prepare complete application documentation, and support the client through the utility/ISO process.

3.1  POI Screening & Selection

The starting point of every interconnection engagement is the identification and ranking of candidate Points of Interconnection. Keentel's POI screening process is a structured, multi-stage analysis that evaluates candidate nodes across the applicable transmission network against a comprehensive set of technical and commercial criteria.

Stage 1 — Geographic & Network Screening

Candidate POIs are identified by filtering all substations and transmission nodes within the relevant geographic area at applicable voltage levels. The initial candidate pool is assessed against available capacity headroom, planned network changes, active interconnection queue positions, and estimated network upgrade cost exposure. This stage typically narrows a broad initial pool of 15–25 candidates to a focused shortlist of 5–8 technically viable POIs.

Stage 2 — Power Flow Validation in PSS/E

Shortlisted POIs are validated using PSS/E — the industry-standard transmission planning and simulation software — loaded with current and future-year network data for the applicable ISO/utility system. New facility models for the generation injection and/or load withdrawal are built and injected into the network model at each candidate POI, and preliminary power flow checks confirm basic technical feasibility.

Stage 3 — Ranked POI Recommendation

All evaluated POIs are ranked and presented in a comparative POI Ranking Table scoring each candidate against: available capacity, estimated network upgrade cost, queue position, voltage compliance, system strength, application timeline, and jurisdiction suitability. A clear, justified recommendation for the optimal POI is provided — giving the client a single, well-supported answer rather than a list of options to navigate independently.

3.2  Steady-State Power Flow Analysis

AC power flow simulations are performed in PSS/E across the full range of facility operating scenarios to assess the transmission network's response to the new injection or withdrawal under normal conditions:

• Peak load (Heavy Summer) and light load (Light Winter) study cases
• Maximum and partial generation export scenarios (for generation injection)
• Maximum and partial load demand scenarios (for load withdrawal)
• Combined simultaneous operation scenarios (for co-located facilities)
• Net import and net export conditions across all combined operating modes

Power flow results identify thermal overloads on transmission lines and transformers, voltage violations at the POI and adjacent buses, and the first limiting system element that constrains load service or generation deliverability. These findings directly inform POI selection and preliminary network upgrade identification.

3.3  N-1 Contingency Screening

N-1 contingency screening is performed in PSS/E to assess the network's response to the loss of a single transmission element under the new facility's operating conditions. This is a client-side pre-screening study to support POI selection — it is not a full NERC TPL-001 transmission planning study, which is the utility/ISO's responsibility.

The contingency screening set includes key transmission line outages, transformer outages, largest generator loss events, and facility-specific contingencies. For each contingency, PSS/E evaluates thermal loading on key transmission elements, bus voltage levels near the POI, and system stability indicators. Results are used to rank POI candidates and identify preliminary network upgrade requirements.

3.4  Short Circuit & Breaker Duty Analysis

Short circuit analysis quantifies the fault current contribution from the new generation or load facility at each candidate POI and assesses its impact on existing network equipment. This is performed as a client-side pre-screening study using PSS/E's short circuit module and serves two purposes: informing POI selection and developing the short circuit models required for the interconnection application package.

For Generation Injection

Generator fault current contribution is modeled using correct subtransient reactance and fault current injection profiles. Three-phase bolted and single line-to-ground fault studies are performed at each candidate POI to assess fault current levels, breaker interrupting duty adequacy, and bus fault duty compliance.

For Load Withdrawal

Large industrial loads — particularly those containing arc furnaces, large motors, and variable-speed drives — can make significant fault current contributions that must be accurately modeled. Composite load impedance and motor contribution characteristics are incorporated into the fault study model to produce a realistic assessment of the facility's fault current impact.

3.5  Reactive Power & Voltage Compliance Assessment

Reactive power management is one of the most critical — and most frequently underestimated — aspects of both generation injection and large load withdrawal interconnections.

For Large Load Withdrawal

Steel plants, data centers, manufacturing facilities, and other large industrial loads typically operate at lagging power factors and impose significant reactive power demands on the transmission network. Keentel assesses reactive power requirements across the full load range, evaluates voltage regulation performance at the POI, and sizes reactive compensation systems — including capacitor banks, STATCOMs, and synchronous condensers — to meet ISO/utility voltage and power factor standards. Where arc furnaces are present, dynamic reactive compensation requirements and flicker emission assessment are also addressed.

For Generation Injection

Generators are required by MISO, TVA, and other ISOs to demonstrate reactive capability compliance through P-Q curve analysis. Keentel assesses the generator's full reactive capability envelope, evaluates voltage control mode options, and prepares the reactive capability documentation required for the interconnection application. Where the generator's native reactive capability is insufficient to meet ISO requirements, supplemental reactive support options are identified and sized.

3.6  System Strength & Short Circuit Ratio (SCR) Assessment

System strength — measured through Short Circuit Ratio (SCR) and Weighted Average Short Circuit Ratio (WASCR) — is an increasingly critical study requirement for generator interconnections as the North American grid transitions to higher proportions of inverter-based resources. A low SCR at the POI can cause voltage instability, active power oscillations, and protection coordination failures that threaten both the generating facility and the broader network.

Keentel's SCR assessment calculates the short circuit capacity at each candidate POI relative to the rated MW output of the generation facility, evaluates interactions with nearby inverter-based resources, and compares SCR values across Heavy Summer and Light Winter study cases. Where SCR thresholds are not met, Keentel identifies mitigation options including alternative POI selection, synchronous condenser installation, and grid-forming inverter control strategies.

  A comparative SCR assessment across multiple candidate POIs is one of the most valuable outputs of Keentel's pre-screening study — enabling the client to select a POI with adequate system strength before investing in formal utility study costs.

3.7  PSS/E Dynamic Model Development

PSS/E dynamic models are a mandatory submission requirement for formal interconnection applications with MISO, TVA, and most other ISOs and utilities. These models allow the utility and ISO to simulate the transient behavior of the new facility under system disturbances — a requirement that cannot be waived and must be completed before an application can advance to System Impact Study.

Power Plant — Generation Dynamic Models

Keentel develops complete PSS/E dynamic model packages for generation facilities including:

• Machine model: generator electromechanical characteristics (GENROU, GENSAL, or equivalent)

• Excitation system model: automatic voltage regulator and excitation control (EXAC1, ESST1A, or equivalent)

• Governor / prime mover model: turbine-governor speed control response (GGOV1, IEEEG1, or equivalent)

• Power System Stabilizer (PSS): oscillation damping controls where required by the applicable ISO/utility

• Inverter-based resource (IBR) models: generic renewable energy system models (REGC_A, REEC_A, REPC_A) or manufacturer user-defined models (UDMs) for solar, wind, and battery storage facilities

Steel Plant / Industrial Load — Composite Load Dynamic Models

Accurate composite load dynamic models are required for large industrial loads and are developed by Keentel to include:

• Composite load model (CMPLDW or CMLD): representing the full industrial load mix including arc furnaces, large induction motors, and other load components

• Motor load representation: large motor load fraction, inertia, and protection settings affecting post-fault voltage recovery

• Arc furnace dynamic model: flicker generation and dynamic reactive power demand characteristics

• Load protection models: under-voltage load shedding and motor protection relay representations

All dynamic models are validated through standard PSS/E simulation test cases — including 3-phase fault, SLG fault, and generator trip events — and packaged in the format required by the applicable ISO/utility for formal application submission.

3.8  Interconnection Application Support

Keentel provides complete interconnection application support from pre-application strategy through submission-readiness review. This covers:

• Application strategy: advising on the optimal application pathway — including hybrid vs. separate applications for co-located facilities and MISO vs. TVA jurisdiction selection

• Application form preparation: completing all applicable ISO/utility application forms including MISO Generator Interconnection Request, TVA Transmission Service and Generator Interconnection forms, and large load application forms as applicable

• Technical appendices: facility one-line diagrams, POI description, load/generation profiles, operating assumptions, preliminary protection philosophy, and reactive capability documentation

• Pre-application meetings: leading or supporting pre-application meetings with the utility/ISO to confirm POI, discuss study assumptions, and align on application scope

• Submission-readiness review: final completeness check against ISO/utility requirements before submission

• Post-submission coordination: responding to utility/ISO technical information requests, reviewing study notices, and providing technical advisory support throughout the formal study process
  

4.  Why POI Selection Is the Most Important Decision

The choice of Point of Interconnection is the single most consequential technical and commercial decision in the entire interconnection process. It determines the network upgrade costs the project will be required to fund, the interconnection timeline, the system strength environment the generation facility will operate in, and ultimately the economic viability of the project. Yet many developers and industrials underinvest in pre-application POI analysis — proceeding directly to formal utility application without adequate pre-screening, only to encounter unexpected and costly network upgrade requirements at the System Impact Study stage.

4.1  The Cost Impact of POI Selection

Network upgrade costs — which the interconnecting party is typically required to fund as a condition of interconnection — can vary by tens of millions of dollars depending on POI selection. A POI that requires reconductoring of a heavily loaded transmission line will carry significantly higher upgrade costs than an adjacent substation with adequate spare capacity. Without rigorous pre-screening, developers risk entering the formal utility study process at a POI that is commercially unviable — incurring application fees, study fees, and delays before the true cost exposure is revealed.

  Keentel's pre-application POI screening identifies the lowest-cost, highest-capacity interconnection pathway before a single dollar is spent on formal utility study fees — enabling confident go/no-go decisions early in the project development process.

4.2  The Queue Position Challenge

The interconnection queue is a critical factor in POI selection that is often overlooked. Each ISO and utility maintains a queue of pending interconnection applications, and projects earlier in the queue have priority over network capacity and upgrade cost allocation. A POI that appears technically attractive may be heavily contested by prior queue positions, resulting in high estimated upgrade costs that reflect the project's queue position relative to competing applications.

Keentel's pre-screening process incorporates real-time queue position data for all candidate POIs, enabling the client to identify nodes with minimal queue exposure and better upgrade cost prospects — a factor that can make or break the economic case for a given POI.

4.3  Dual Jurisdiction Considerations

Projects located in areas served by multiple transmission owners or ISOs — such as the boundary between MISO and TVA territory in the Southeast, or areas where multiple utilities overlap — must evaluate POI options across both jurisdictions. The optimal POI may lie in a different jurisdiction than initially assumed, with significantly different upgrade cost profiles, queue dynamics, and application timelines. A thorough cross-jurisdictional POI screening is essential to ensure the best available option is identified regardless of utility boundaries.

5.  Technical Deep Dive — Key Study Concepts

5.1  Power Flow Fundamentals for Interconnection

AC power flow analysis is the foundation of all transmission interconnection studies. In PSS/E, the network is represented as a system of buses (nodes) connected by branches (transmission lines and transformers), each with defined impedance, thermal rating, and voltage characteristics. The power flow solver iterates to find the steady-state voltage magnitudes and angles at all buses that satisfy Kirchhoff's laws and the network's physical constraints.

For a new generation injection, the facility is represented as a PV bus — where real power output and terminal voltage are specified, and the solver calculates the reactive power exchange and network voltage profile. For a large load withdrawal, the facility is represented as a PQ bus — where real and reactive power demand are specified, and the solver calculates the voltage response at the POI and throughout the network. The key outputs for POI assessment are:

• Thermal loading on all transmission elements as a percentage of their normal and emergency ratings
• Voltage magnitudes at all buses — violations of ANSI C84.1 voltage standards are flagged
• Reactive power flows and reactive margin at the POI
• Real and reactive power losses in the transmission system

5.2  Short Circuit Fundamentals

Short circuit analysis calculates the fault current that would flow in the network following a bolted fault at a specific bus. The two most important fault types for interconnection studies are:

• Three-phase bolted fault (3φ): the symmetrical fault that produces maximum fault current at the fault location — used to assess breaker interrupting capability
• Single line-to-ground fault (SLG): typically the most severe asymmetrical fault type for protection system design and zero-sequence analysis

For a new generation facility, fault current contribution is determined by the generator's subtransient reactance (X"d) and the network impedance between the generator and the fault location. For a large industrial load containing motors, the motor impedance and inertia determine the magnitude and duration of the motor's fault current contribution — which can be significant for large electric arc furnace and motor drive installations.

The key metric from short circuit analysis is the X/R ratio at the POI — a high X/R ratio indicates a predominantly inductive fault current that stresses breaker interrupting capability. Breaker interrupting duty is assessed by comparing the calculated fault current against the breaker's rated symmetrical interrupting current, adjusted for the X/R ratio per IEEE C37 standards.

5.3  System Strength & SCR — Technical Explanation

Short Circuit Ratio (SCR) is defined as the ratio of the short circuit MVA at the POI to the rated MVA of the connecting generation facility. A high SCR indicates a strong grid — one that is relatively unaffected by the generator's output fluctuations. A low SCR indicates a weak grid, where the generator's output can cause significant voltage fluctuations and where inverter-based resources may experience control instability.

The NERC guideline threshold for minimum SCR is generally 1.5 for inverter-based resources, though specific requirements vary by ISO and utility. MISO, for example, has published specific system strength assessment requirements tied to its interconnection procedures. Where SCR falls below the minimum threshold, the following mitigation options are typically evaluated:

• Synchronous condenser: a rotating electrical machine that provides reactive power and increases short circuit capacity at the POI — directly raising the SCR
• Grid-forming inverter controls: advanced inverter control strategies that allow inverter-based resources to form voltage references in weak grid conditions — an emerging technology increasingly accepted by utilities
• Alternative POI selection: moving the interconnection to a stronger point in the network with higher inherent short circuit capacity
• Phased generation commissioning: initially operating at reduced output levels until network strengthening upgrades are completed

5.4  Reactive Power & Power Factor — Why It Matters for Large Loads

Large industrial loads — particularly steel plants with electric arc furnaces — impose variable and often highly reactive power demands on the transmission network. This has two significant consequences: power factor penalties imposed by the utility for operating below a specified minimum power factor, and voltage depression and flicker on the network that can affect other customers served by the same transmission infrastructure.

The power factor of an electric arc furnace load varies dynamically as the furnace operates through its melting cycle, generating rapid and large reactive power swings that manifest as voltage flicker on the network. Flicker assessment — quantified using the IEC flicker severity indices Pst (short-term flicker severity) and Plt (long-term flicker severity) — is a standard utility requirement for arc furnace interconnections and directly drives the sizing of dynamic reactive compensation (STATCOM or SVC) requirements.

For generation facilities, reactive capability compliance is a contractual requirement in virtually all ISO/utility interconnection agreements. The generator must demonstrate the ability to operate within a specified power factor range at its high-side bus across its full real power output range — typically 0.95 power factor leading to 0.90 power factor lagging at rated MW output. Failure to demonstrate this capability during the formal study process can delay the interconnection agreement and trigger requirements for additional reactive support equipment.

6.  How Keentel Engineering Supports Your Project

Keentel Engineering serves as the client's dedicated technical partner throughout the pre-application and application phases of the interconnection process. Our role is to ensure that the client enters the formal utility study process with the best possible POI, the most complete and technically robust application, and the highest likelihood of a successful interconnection outcome.

Keentel Engineering's interconnection study services are built on one principle: the client's best interests come first. We provide honest, technically rigorous analysis — not the answer the client wants to hear, but the answer they need to make informed decisions.

7.  Frequently Asked Questions (FAQ)

The following questions are commonly raised by developers, industrial clients, and project owners during the interconnection study process. Keentel Engineering's answers are provided to help clients better understand the technical and commercial dimensions of the process.

The Bottom Line

The Texas grid is being asked to host more new load in the next five years than it has built in the last fifty. The legacy single-study, firm-service-only interconnection model cannot deliver that capacity in time.

BYOG, CLR, and WLPUN are the three frameworks Texas is using to bridge the gap — letting Large Loads come online with self-supply and as-available grid service while transmission catches up. They are not interchangeable, and the regulatory boundaries between them are still being drawn through the Batch Zero process scheduled for finalization in mid-2026.



For developers, the implication is clear: the framework you choose determines your speed-to-power, your operational obligations, your settlement exposure, and your capital deployment risk. Understanding the distinctions between BYOG, CLR, and WLPUN — and the constructs that sit beneath each — is no longer a regulatory nicety. It's a core part of building large-scale compute infrastructure in ERCOT.