SmartGridNews.com The insider's guide to the modernization and automation of electric power
Triangle MicroWorks Makes Interoperability Easier By Erich Gunther Oct 21, 2008 - 1:21:40 PM
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 edition of SGN’s Tech Take evaluates third-party protocol stacks from Triangle MicroWorks (TMV). As you will read, TMV’s products score very high against our Smart Grid metrics. Even so, they are not enough in and of themselves to guarantee success. To understand my evaluation, you need to grasp three essential elements:
· The role of the SGN Scorecard · The purpose of a protocol stack · How TMW measures up
The role of the SGN Scorecard
The SGN Scorecard was developed because many of today's products do not adhere to Smart Grid principles. They may support "least common denominator" Smart Grid applications such as meter reading. But they are not adequate for distribution automation, plug-in hybrid electric vehicle management, microgrids, demand response and many other future applications.
The SGN Scorecard is a checklist that measures whether products meet minimum standards for a Smart Grid. We will use it as the benchmark for all Tech Talk reviews. You are invited 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 a protocol stack
Smart Grid devices need to communicate real-time (operational) data as well as slower (non-operational) data. Real-time data maintains common control and status transactions. Non-operational data supports activities such as historical archiving and forensics. Communications between devices requires a software protocol stack. The stack is a “translator,” converting application-based data so it can flow back and forth over the low-level communications system.
Both manufacturers and users tend to concentrate on the device capabilities. They have little desire to become experts at the bits and bytes level of modern communications protocols. Enter third-party software stacks, which allow manufacturers and users to quickly incorporate industry-standard protocols without the need to dive down into the weeds each time.
High-quality protocol stacks have several benefits. For one thing, they substitute stable, proven software from a specialist for unproven, custom software written for a specific project. For another, they solve the updating problem. Even if users become experts in protocol stacks, the ongoing maintenance becomes a major issue since standards inevitably mature and evolve.
The purchase of a protocol stack makes economic sense from this broader perspective. Protocol stacks separate the device functionality from the communications functionality. This independence allows vendors and users to concentrate on device functionality while the stack vendor concentrates on maintenance of the protocol.
How TMW measures up
Triangle MicroWorks (TMW) offers stacks for a variety of industry-standard protocols. This Tech Take examines TMW's DNP3 and IEC61850 offerings, two of the Smart Grid’s most important protocols.
TMW provides an object-oriented approach to protocol stacks. For each object at the communication protocol level, the user defines an access mechanism. Users can safely ignore the details of how the protocol communicates these objects "across the wire" and simply concentrate on what needs to be transferred. This approach allows stack vendors to extend a protocol (for example, adding TCP/IP to a serial protocol) without impacting any user software.
Scalability - The TMW protocol stacks have no pre-defined limits; the limits are based solely upon the target hardware. It has been successfully implemented both in very simple systems and in systems with hundreds of devices on a single network. TMW supports DNP3 transport over serial interfaces, which is inherently limited to a few dozen devices, as well as TCP/IP and UDP/IP which support an unlimited number of devices. The IEC61850 version supports TCP/IP as well as geographically limited broadcast services (such as GOOSE used for high-speed status transfer). The IP-based protocols can fully co-exist with other IP-based protocols.
Openness - Both DNP3 and IEC61850 contain many optional features. If a new device is brought into the system which requires a previously unimplemented feature, then that feature can be simply "turned-on" and then used as if it had always been part of the system. Pre-tested components ease the integration efforts.
Standardization - TMW strongly supports standardization activities and they support ONLY standards-based solutions. The corporate officers of TMW have helped to write both DNP3 and IEC61850 and they continue to invest heavily in the various standards bodies (DNP3 Technical Committee and IEC Technical Committee 57).
Security - The DNP3 protocol stack fully supports the draft standard DNP3 authentication. Due to the underwhelming power industry support for secure IEC61850, TWM has chosen not to implement the security features at this time. I am very disappointed with this market reaction for secure 61850 (or rather lack of reaction). But I am hopeful that the user community will come to their senses with regards to security and create a market that takes advantage of the intellectual property that is available to service it.
Upgradability - Vendor and users that opt to purchase a protocol stack enjoy independence from protocol maintenance. If the user side is implemented properly, changes to the base protocol require NO changes to any user code but merely a replacement of the protocol library within the application. Because the user applies pre-tested components, the overall device testing becomes a simple matter of a few end-to-end consistency checks.
Why TMW is not the entire answer
The integration of third-party stacks into existing software is almost too easy. The stack vendors provide simple examples of integration without explaining the "why" of the process. Before using a third-party stack, a user/vendor must understand the expectation of the "other end of the wire" to allow meaningful data communications, as opposed to the simple transport of bits and bytes. This is not necessarily a stack vendor problem, but a user education issue. This leads to a sense of complacency that must be overcome to spend some of that time saved in implementation on end-to-end testing for application level interoperability and security vulnerabilities that may have been introduced by user code.
Triangle MicroWorks Smart Grid Scorecard: 88 out of 100
Conclusions
Incorporation of industry-standard protocols into products using pre-tested third-party software makes sense in many ways. It allows manufacturers and users to concentrate on their core competencies while providing a standard plug-and-play system solution. There is no excuse for a vendor to implement home-brewed, proprietary solutions when tools such as this are available. However, the ease of integration can lead to products that transfer data perfectly yet don’t communicate in useful ways.
Research Credit: Bruce Muschlitz – Email Bruce Muschlitz
Erich W. Gunther is Chairman of EnerNex Corporation. He chairs the UtilityAMI / OpenHAN standards group and serves on the GridWise Architecture Council. Bruce Muschlitz is a consulting engineer in utility communications for EnerNex and he is actively involved in DNP3 and IEC 61850 protocol standards development.
EPRI IntelliGrid Architecture Web site
Subscribe to our FREE eMail News Alert!
Smart Grid Newsletter (SGN) is the insider's guide to the Smart Grid revolution. It consists of a FREE bi-monthly email summary, along with a companion Web site that contains the full stories and other helpful materials. Benefits of subscribing: SGN is the only central source for all of the news, trends, research and marketplace information relevant to grid automation. In it, you will read about cutting edge technologies; successful pioneers and how they got ahead; regulatory changes that could unleash new markets; the latest research; and new opportunities for sales of grid-related products and services. © Copyright 2008 SmartGridNews.com |