Planning considerations
Expansion drivers
Customer needs
Planning criteria
System performance criteria
Capacity ben. margin criteria
Transmission reserve margin
Facility rating criteria
Model building criteria
Facility condition criteria
Planning zones
System alternatives
Load forecast criteria
Economic criteria
Environmental criteria
Variations on ATC criteria
Other considerations
Methodology & assumptions
NERC compliance

New 11-18-11 - Updated Planning Criteria: A copy of our current Planning Criteria can be found here.

The criteria outlined on the web site refers to the version used for the 2011 Assessment.

Planning criteria

We employ various system planning criteria to ensure that we develop a reliable and robust transmission system. Our aim with these criteria is to support effective competition in energy markets, to reliably deliver power to systems connected to our system and customers dependent on our system, to provide support to distribution systems interconnected to our system and to deliver energy from existing and new generation facilities connected to our system.

These criteria may be revised from time to time. Situations that could precipitate such a change could include, but are not limited to new system conditions, new technologies, new operating procedures, extraordinary events, safety issues, operational issues, maintenance issues, customer requests, regulatory requirements and reliability council or NERC requirements.

The planning criteria are listed under the following headings:

Planning tools  

Our planning engineers frequently use the following computer applications to simulate the impact of potential future events on the transmission system. The same applications are used to determine how proposed solutions would address any identified adverse impacts.


  • Ventyx PROMOD – predicts the cost of producing energy to serve customers.
  • Burchett Inc. PROMOD Analysis Tool (PAT) – post-processing analytic capability for PROMOD results
  • General Electric MARS – determines “Loss of Load Expectation”, a measure of the ability of system resources to meet customer demand
  • Siemens (PTI) MUST – calculates the capability of the system to transfer power from one area to another while respecting thermal limitations
  • Siemens (PTI) PSS/E – calculates static and dynamic power flows
  • PowerTech VSAT/TSAT/PSAT/SSAT – VSAT calculates the capability of the system to transfer power from one area to another while respecting voltage limitations. TSAT assesses the dynamic behavior of the system under specified condition. PSAT calculates static power flows.  SSAT analyzes the small signal stability of the system
  • Power World Corp PowerWorld – calculates static power flows with a visual interface
  • V&R Energy Systems Research POM/OPM – determines “Expected Unserved Energy”, a measure of the ability of the system to deliver resources to meet customer demand.


Copyright 2011 American Transmission Company. All Rights Reserved