IntelliTEAM® -- Designed With the Smart Grid Utility in Mind

In SGN's Tech Take articles, power engineer and architect Erich Gunther evaluates actual products and services against the SGN Smart Grid Scorecard. Unless disclosed explicitly at the beginning of the article, neither SGN nor Erich Gunther has received any compensation from the vendor nor do they own stock in the company.

 

This article examines the IntelliTEAM II^® Automatic Restoration System from S&C Electric Company (S&C), a collection of products that provides an automated response to feeder line faults.  The system also provides improved visibility and versatility for managing a distribution network.  IntelliTEAM II builds on S&C’s experience with earlier versions, adding considerable flexibility and capability. 

 

Although it has shortcomings, IntelliTEAM II offers compelling benefits today with strong potential for expanded Smart Grid applications in the future. It has significant openness issues for us standards geeks (see below for details), but it generally adheres to the key elements of a standards-based Smart Grid system.

 

To understand my evaluation, you need to grasp four essential elements:

·         The role of the SGN Scorecard

·         The purpose and components of an automatic feeder sectionalizing and restoration system

·         IntelliTEAM II benefits, including the potential for additional benefits when IntelliTEAM III arrives

·         IntelliTEAM II shortcoming (which it shares with distribution automation solutions from other companies)

 

The role and importance of the SGN Scorecard

The SGN Scorecard was developed for a very important reason: most of today's products do not adhere to Smart Grid principles. They do not support the requirements envisioned by Smart Grid researchers such as EPRI, the California Energy Commission's Public Interest Energy Research program, the Modern Grid Initiative and DOE's GridWise program. Nor do they adhere to the mandates in the Energy Independence and Security Act of 2007. 

 

In particular, several elements of the EPRI IntelliGrid Architecture are critical to implementing a Smart Grid:

·         Proven, Internet derived communication technologies

·         Service based architecture at the enterprise level

·         Self healing technology

·         Well defined interfaces and points of interoperability

·         Application of industry and international standards

·         Built in security and network management

 

The SGN Scorecard is a checklist that measures whether products meet minimum standards for a Smart Grid. We use it as the benchmark for all Tech Talk reviews. We invite you to use it free of charge for your own evaluations. For a further explanation and a blank version you can copy freely, download the PDF version of the Scorecard (see link below).

 

The purpose of automatic feeder sectionalizing and restoration

Automatic feeder sectionalizing and restoration – which often goes by the name Fault Location Isolation and Service Restoration (FLISR) – is a core application for distribution automation.  In their most basic form, these systems detect a fault, determine its location, and open the nearest available switches (or fault interrupters) during a tripped state of the fault-clearing recloser or breaker. This isolates or sectionalizes the faulted segment from the rest of the feeder.

 

Then, after extensive validation, the system automatically closes switches to restore power to the unfaulted segments.   The system operates under the jurisdiction of the system operator, who is able to turn off automatic operation as necessary.  When operating automatically, these systems provide the self-healing capability that is a key benefit of a Smart Grid.

 

Systems can typically be configured to operate in any of several modes such as:

·         Manual

·         Fully automatic

·         Semi-automatic (usually involving operator actions, with recommendations for the restoration phase).  Note: IntelliTEAM does not support this mode

 

Different vendors offer different architecture options, includeing:

·         Distributed, able to operate independently (the S&C choice)

·         Centralized (based on a GIS-based distribution system model)

·         Substation-centric (with a controller at the substation)

·         Hybrid involving portions of two or more architectures

 

The benefits of FLISR to the utility and its customers include improved SAIDI/SAIFI performance and reduced field staff effort to locate faults.

 

The S&C IntelliTEAM II System

IntelliTEAM II accomplishes FLISR functionality by equipping each switch (or fault interrupter) with a controller unit (“team member”).  That controller is part of a “team” that communicates on a peer-to-peer basis to accomplish tasks.  Once the system is configured and enabled, it is able to operate without any further interaction from an operator or external host at the SCADA master or substation. 

 

A key aspect is the validation process that is completed before any automatic restoration actions.  This ensures that all team members are communicating and functioning, that only unfaulted segments will be restored, and that the new sourcing feeder(s) and substation(s) can handle the additional load.

 

Validation requires coordination between teams and substations, which is accomplished by assigning a team member type to each S&C switch controller. The different team member types are:

·         Source Substation (normally closed)

·         Load Tie (normally closed)

·         Source (normally closed)

·         Load (normally closed)

·         Tie (normally open)

·         Tie Substation (normally open)

 

To work independently without a host, the system must share data between controllers.  The S&C approach invokes a “coach” serving as a software agent (data packet) that is continuously passed from one team member to the next.  Each team member acts on the data based on its type as listed above.  Actions include operating the associated switches or fault interrupters.  An individual switch or fault interrupter can be -- and most often is -- associated with more than one team.

 

Peer-to-peer communications is another fundamental aspect.  It is accomplished with S&C-supplied UtiliNet® spread spectrum mesh radios using unlicensed 900 MHZ band frequencies or with other IP modems (wired or wireless). The benefits of the UtiliNet mesh radio include the ability to start small without needing a full radio implementation.  On the down side, utilities that have implemented more than a few team members have found that the radios have a limited throughput and may impose long delays.

 

The coach or data packet is continuously routed between the radios, providing the team members (switch controllers) the needed data for operation.  A back haul facility to the control center can be based in the substations or other locations.  The team members use DNP level 2 for communications.  However, the content of the coach is proprietary. 

 

S&C's Product Lineup (IntelliTEAM II)

Field Equipment:

·         Scada-Mate® overhead switches

·         Motor operated PMH® pad-mount switches

·         Motor operated Vista® switchgear

·         Reclosers by other manufacturers

·         Feeder breaker relays by other manufacturers

·         UtiliNet® spread-spectrum radios (and repeater radios)

·         IntelliTEAM II software logic

 

Control Centre Equipment:

·         S&C Proxy Server (optional)

·         WinMon Configuration Software (optional)

·         CellNet RadioShop^® (optional)

Universal Interface Module (new):

·         An interface module introduced to address the need for the IntelliTEAM systems to communicate with other devices at the substation, such as RTU and protection relays for coordination.  It works with IntelliTEAM II and III.

 

S&C's Future Product Lineup (IntelliTEAM III - new):

·         IntelliRupter PulseCloser^® for overhead switches

·         SpeedNet^® radios

 

Evaluating the components

S&C’s overhead and pad mount switches have been strong offerings in their own right.  However, they did not offer the fault interruption capability desired by many utilities. The IntelliRupter PulseCloser switches address this issue and also enable the system to “pulse close.”  The result is a feeder switch that can open under fault, test for a temporary or permanent fault, coordinate with upstream devices, and isolate a faulted segment very quickly.  In addition, all this is accomplished with very low energy drawn on a faulted system, reducing wear and tear on equipment during the “pulse closing” actions.

 

The UtiliNet radios promised an innovative mesh solution when first introduced.  However, due to limited throughput and long latency, they have since become a source of concern for utilities with larger installed bases of IntelliTEAM equipment for SCADA communications.  Workarounds include installing fiber or a separate radio dedicated to SCADA.  S&C is addressing this issue by introducing new SpeedNet IP-based radios, which provide considerable improvement in throughput (650kbps vs. 20kbps), latency (6 mSec vs. 300 mSec), power use, routing tables, priority levels and data encryption.  When they arrive, it may be possible to use these improved radios to upload oscillographic records, download software upgrades and carry AMI, DR, DER and other distribution automation data types, although careful evaluation and system design will be important.

 

The IntelliTEAM II switch controllers provide the functionality of a conventional controller, including the option for direct communication to a DNP SCADA master in parallel with peer-to-peer communications to the other team members.  The controllers communicate to SCADA or other devices using serial DNP3 Level 2 that has been independently verified according to DNP User Group testing requirements.  The next-generation of IntelliTEAM III switch controllers will be IP-based and will add enhancements including the automatic development of IntelliRupter curves to coordinate with upstream devices. 

 

The control center equipment may include a Proxy Server that polls all IntelliTEAM devices and populates the real-time database for access by the EMS/DMS systems.  The WinMon Configuration Software is used to configure the switch controllers remotely and provide engineering tools.  The CellNet RadioShop is used to configure the UtiliNet radios.

 

In the case of substations using electro-mechanical relays, another module is needed to automate the feeder segment closest to the substation.  This module, called the Universal Interface Module (UIM) can be located at the substation or at the control center. S&C recently introduced the UIM for a number of very good reasons:

·         To coordinate with the substation Intelligent Electronic Devices (IEDs) to automate the feeder segment closest to the substation.  The UIM uses the breaker status and the status of the first IntelliTEAM switch to control the substation breaker (in parallel with other control mechanisms such as protection and SCADA).  In addition, the UIM turns off automatic operation during scenarios such as recloser blocking, under-voltage or under-frequency events. 

·         To provide an interface between IntelliTEAM and non-S&C IEDs on feeders (e.g. recloser controllers) and in substations (e.g. protection relays and RTUs) to coordinate FLISR functions.  The UIM works with both IntelliTEAM II & III and functions as a team member while interfacing to other IEDs. The UIM supports both serial and IP communications.

 

The UIM is the component that provides a “well defined point of interoperability” in an otherwise proprietary system and is essential to consider this system as “open” in any sense of the word.

 

Note: For clarification, although IntelliRupter and SpeedNet are necessary hardware components for the IntelliTEAM software system to work, they are different development projects for S&C.  The hardware components are available now and will work with IntelliTEAM II systems for the time being.  IntelliTEAM III software is a future offering for enhancement of protection and other features.

 

How IntelliTEAM II measures up against the competition

Comparison should be done on a number of levels, namely: distribution system design, architecture and product/system. 

 

Distribution System Design: Feeder automation systems that are switch controller based (as discussed in this article) are generally applied in various configurations of loop designs (open tie) that are frequently found in urban areas.  Recloser based designs work well in radial designs more common in rural areas.

 

Architecture: S&C has elected to go with a fully distributed architecture (a key IntelliGrid and Smart Grid general concept):

 

Advantages of Distributed Architecture	Advantages of Centralized Architecture
·         Able to operate even if communications to SCADA fails ·         Scalable installations not requiring large upfront investment in communications ·         May be faster than other methods ·         No SCADA or DMS required (but must be supported if present) ·         No GIS model with updating needed	·         Flexibility for abnormal conditions ·         Ease of adding new functions ·         Operator awareness and control ·         No unnecessary switching

 

Note:  a substation-centric approach is an alternative that carries a lower cost but is more restrictive in the number of switches and more limited in complex situations.

 

Product/System: Although there are multiple suppliers addressing centralized and substation-centric architectures, few besides S&C can offer a field-proven system with a large installed base.  The other well known solution is Distribution Vision 2010 (DV2010), which is a national organization comprising nine utilities led by We Energies and a number of suppliers including Cooper Power and NovaTech.  The DV2010 system design is organized into four tiers as follows:

·         Tier 1: Autonomous Protection

·         Tier 2: Distributed Automation Logic

·         Tier 3: Local Area Control - Substation

·         Tier 4: Wide Area Control - Region

 

The initial focus has been on improving recloser control implementations and communications, as well as the development of Premium Operating Districts (PODs).  To date, a number of pilots at different tiers have been implemented.  The concepts deployed at Tier 2 are similar to IntelliTEAM II.

 

Room for improvement

The main concerns with the IntelliTEAM II system are:

 

The current UtiliNet radios require improvement in throughput, latency, routing, message priorities and cyber security.  S&C is in the process of introducing new SpeedNet IP-based radios, as noted above, which will represent a considerable improvement.

 

Communications with other wireless technologies is unproven.  As utilities implement ADA and AMI, they will utilize multiple communication solutions. S&C indicates that it products should work in that scenario, but it has not yet been demonstrated by customers.  Note that the IntelliTEAM II switch controllers use serial-based communications.  Therefore, interfacing the IntelliTEAM II components to an IP wireless system such as Silver Springs™ will require a terminal server solution coupled with a method for handling DNP to IP addressing.  (The serial issue is addressed with the IntelliTEAM III switch controllers.)

 

Security is not strong enough. Although the NERC-CIP standards for cyber security do not directly apply to feeder automation, it is nonetheless is an important concern.  The degree of vulnerability varies greatly depending on system components.  For example, the use of dedicated fiber instead of wireless considerably reduces vulnerability to some threats.  Previous generations of IntelliTEAM II had minimal additional security.  However, S&C is currently offering two new security enhancements: 1) new firmware for the Series III radios to support AES encryption and 2) new IntelliRupter PulseCloser^® overhead switch with a switch controller unit includes an extensive suite of security applications.

 

Proprietary controls. S&C’s new UIM enables products from other vendors to act as team members, such as IEDs on feeders (e.g. reclosers) and in substations (e.g. protection relays and RTUs). Even so, S&C maintains the proprietary nature of the control mechanism. I understand the need to protect S&C’s intellectual property investment and the operational integrity of the control strategy.  Nonetheless, I view this as a drawback.  Could there be room in the future for a lower cost software license, API or chip set solution?

IntelliTEAM II^® Smart Grid Scorecard: 69 out of 90 (77% or 77 out of 100)

Metric	Score (10 is best)	Comments
Impact	10	The system certainly can make the distribution network more reliable.
Openness	7	The addition of the UIM has made the system more open.
Standardization	8	The system uses a tested implementation of DNP3 Level 2.  However, the contents of the coach are proprietary.
Security	5	Latest UtiliNet and SpeedNet radios support AES encryption.  Latest switch controller has extensive security applications.  Previous versions of IntelliTEAM equipment offer minimal security applications.
Manageability	7	Supports remote configuration and enabling/disabling of the teams.
Upgradeability	6	This has been improved with the SpeedNet radios and IntelliTEAM III.
Scalability	9	This is the best approach for feeder automation in terms of scalability.  There is some limitation with the UtiliNet radios, but that will be resolved with the new SpeedNet radios.
Extensibility	8	The “team” approach aids in extensibility.
Self-Healing	9	This is a great example of a self-healing architecture for distribution.
Interactivity	N/A	Interaction with the consumer is not applicable so this metric is not counted in determining the total score.
Total	69	69 out of 90 or 77%

Overall, IntelliTEAM II scores reasonably well against the EPRI IntelliGrid Architecture elements and SGN's Smart Grid Scorecard.  I am particularly impressed with the efforts by S&C to address the key challenges their customers have faced with IntelliTEAM II.  Once the IntelliTEAM III systems have been operating for a period of time, it will be appropriate to revisit the scoring and I believe it will score even higher at that time.  Addressing security concerns and finding a way to make the system more open and able to work with other vendor automation devices with full team functionality would raise the score significantly.

 

"What about real-world performance? Calgary-based ENMAX Power won the 2004 DistribuTECH Automation Project of the Year award based on the IntelliTEAM II system.  (See chart below.) In addition, the system received an engineering award in Ontario, Canada. Systems have been installed in North America with approximately 1000 devices.  On the down side, larger implementations have encountered performance issues with the radio communications.  However, S&C has addressed the issue by offering the SpeedNet® radios providing significant performance and feature enhancements."

 

Chart Courtesy of ENMAX Power

 

Research Support: Ron Farquharson, EnerNex Corp.

 

Erich W. Gunther is Chairman and CTO of EnerNex Corporation. He chairs the UtilityAMI / OpenHAN standards group and serves on the DOE GridWise Architecture Council.

 

   Email Erich W. Gunther

   S&C website

   Smart Grid Scorecard (PDF)

   EPRI IntelliGrid Architecture website

   GridWise Architecture Council website
   Summary Table of SGN Tech Take Product Reviews