The North American SynchroPhasor Initiative (NASPI) is a joint effort between the U.S. Department of Energy (DOE) and the North American Electric Reliability Corporation (NERC).  The goal is to improve power system reliability through wide-area measurement, monitoring and control. This will be achieved by facilitating a robust, widely available and secure synchronized data measurement infrastructure for the interconnected North American electric power system.  It also includes associated analysis and monitoring tools for better planning and operation, and improved reliability.  This article provides an overview of NASPI, including recent accomplishments, current status, and planned activities.

Through the 1990s, utilities began to deploy phasor measurement units and investigate the ability to enhance situational awareness through improved wide area visibility.  The technology soon became very helpful in the investigation of blackouts and disturbances, particularly the western interconnection breakup that occurred on August 10, 1996.  Similarly, the August 14, 2003 blackout illustrated the role of this technology for disturbance analysis.  To facilitate the development of this technology, particularly to foster an environment of information exchange between utilities, the U.S. DOE initiated the Eastern Interconnection Phasor Project (EIPP) in October 2002, building on over a decade of experience in the western interconnection.  In 2007, NERC formally joined DOE in the effort, and expanded it to include all interconnections within North America.  At this time the EIPP was renamed to NASPI.

NASPI Organization

NASPI is structured as a working group made up of voluntary members from electric power organizations, reliability coordinators, suppliers of monitoring and communications network hardware and software, and researchers from industry, universities, and national laboratories.

The working group is composed of five task teams who focus on various aspects of developing and deploying synchrophasor measurement technology:

• Data & Network Management
• Operations Implementation
• Performance and Standards
• Planning Implementation
• Research Initiatives

DOE, through the Consortium for Electric Reliability Technology Solutions (CERTS) and in collaboration with NERC, provides technical support to the task team activities. The task team leaders, together with the DOE program manager and representatives from NERC and CERTS, make up a Leadership Committee, whose role is to plan and coordinate the working group activities. An Executive Steering Group provides oversight to the working group, engages the power industry at a senior management level to spread the word about the benefits of system-wide measurements, and enlists support for the program.

The NASPInet Concept

When synchrophasors were first deployed and networked, the network architecture relied on a centralized architecture, with point to point links interconnecting the phasor measurement units to the ultimate application.  The IEEE C37.118 protocol was developed to standardize the streaming synchrophasor data traffic, and phasor data concentrators were developed to provide time alignment between the various signals.  These concentrators also provided a framework for interfacing to the application(s), providing data archiving and access to historical data, and other functions such as managing specific data flows between organizations.  Because synchrophasor applications are undergoing a transformation from research-grade to production-grade operations and planning applications, there exists a need to develop a new paradigm with which the synchrophasor data can be disseminated and shared between organizations. 

Under the leadership of the NASPI Data and Network Management Task Team, the concept of a distributed architecture linking the providers of the data (publishers) with applications (subscribers) using a publish-and-subscribe middleware and data bus concept has been developed.

Currently, the NASPInet architecture is at a conceptual design phase, and a detailed specification is under development.  The vision is that this specification can be used by hardware or software vendors to provide an interface to NASPInet, either as a publisher or as a subscriber.  The unifying element that will provide this interface is a phasor data gateway. 

Following the release of the NASPInet specification, there will be pilot demonstration projects to further refine and modify this specification based on lessons learned from interconnecting multiple vendors and a spectrum of applications in a common architectural framework.

NASPI Website Repositories

Another short-term initiative being undertaken by NASPI in 2009 is the development of multiple repositories on the NAPSI website (http://www.naspi.org/). 

These include:

• The Research Repository, sponsored by the Research Initiatives Task Team, allows researchers to describe their research projects and provide links to pertinent resources that may be available and of interest to other researchers in the synchrophasor arena
• The Tools Repository, sponsored by the Performance and Standards Task Team, provides a summary description of the various synchrophasor tools currently used by industry in various stages of development, and
• An emerging (proposed) Hardware Repository, which will provide a listing of phasor-capable measurement hardware, either stand-alone phasor measurement units or other devices, such as fault recorders of programmable protective relays that can provide time synchronized phasor measurement outputs

These are currently in various stages of development.

Baselining

Both the Planning and Operations Task Teams are currently involved in baselining activities, or, in other words, determining “normal” phase angles so that abnormal conditions can be better defined and alarmed.  The task teams are taking complimentary approaches to determining these “normal” phase angle separations. 

The Operations Task Team is looking at observed angle separations for key phasor measurement locations, and evaluating this data over historical timeframes.

The Planning Task Team is performing model-based studies to assess the phase angle separation under known heavily stressed conditions, and correlating these angles with specific changes to the operating conditions in the basecase model study. 

Between these two approaches, the goal is to develop a more rigorous methodology for determining the thresholds at which the real-time monitoring tools should be alarmed based on the observed phase angle separation between monitoring locations.

The success of NASPI is the result of the tireless efforts of the many members of the NASPI Working Group and its Leadership Team in developing and deploying synchrophasor technology in the North American electric power grid.

NASPI is helped to a great extent by the sustained leadership and support from DOE (Phil Overholt) and NERC (Stan Johnson and Bob Cummings) in facilitating collaborations.