Smart Grid: Does your power system always have a pulse? - Smart Grid News

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Does your power system always have a pulse?
By Erich Gunther
Mar 26, 2008 - 3:00:00 AM

Date of Tech Take: March 18, 2008

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

As a result of their failure to meet the basic principles, most of today's communication networks -- whether for automatic meter reading (AMR) or for advanced meter infrastructure (AMI) -- are inadequate. 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.

SGN Warning: To avoid buying dead-end products, utilities must provide their vendors with a comprehensive and prioritized list of requirements covering current and future functionality. And then they must get written assurances from vendors that their products meet those requirements.

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. 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 permanent power quality monitoring equipment

Real time monitoring and control is a key element of any Smart Grid. The industry has been employing basic voltage, current and power sensing remote terminal units (RTUs) for this purpose for decades. This information is key to the real time command and control of the power system. Classic RTUs, however, are relatively simple, low-resolution devices that report only the most basic parameters of the power system. This is akin to basic health parameters such as pulse, blood pressure and respiration rate. In today’s Smart Grid, we need additional information about the state of the system that is more like advanced blood tests and a complete ‘body-scan’ like an MRI. The additional information provided by permanently installed and network-connected power quality monitoring enables operators and engineers to measure the quality of service, react more effectively to unexpected system events, and provide the forensic information necessary to determine cause, effect and future mitigation methods for more serious system events.

The Dranetz-BMI product lineup

Founded in 1963, Dranetz-BMI is headquartered in Edison, N.J. and has been a pioneer in power quality instrumentation for more than 40 years. Dranetz-BMI engineers and manufactures a wide range of handheld, portable and permanently-installed power quality and energy management instrumentation for utility, industrial, facility and electrical contractor customers. In the late 90’s, Dranetz-BMI released the first components of the Signature System™, a family of advanced power quality monitoring equipment. This release was ground breaking at the time in its support for standards-based measurements and communications. It was the first of its kind to embed a web server in the measuring instrument itself, provide full support for state-of-the-art Internet and power system specific communication protocols, and perform its measurements using current power measurement standards.

The following products are included (not a comprehensive list) in the Signature System™ series of equipment:

· 5530 DataNode® – advanced power quality and quantity measurement

· 5500 Series InfoNode® – field hardened data concentrator with built-in web-based visualization

· 5590 DualNode™ – combines the 5530 DataNode® and the 5500 InfoNode® in a single package

· 5560 QOS DataNode® – advanced power quality measurement meeting the European EN50160 standard

· 5540 DataNode® – basic power monitoring for energy management applications

· Advantech® ADAM 4000/5000 Series DataNode – versatile general data acquisition and control

· GE kV DataNode® – provides advanced power measurement and revenue metering capabilities

· Answer Modules – add-in software modules providing highly intelligent analysis of system events

Evaluating the components

In the interest of full disclosure, I must admit a certain bias towards this vendor. I was once employed by Electrotek Concepts, Inc. – a sister company of Dranetz-BMI – and I was involved in the development of the Signature System™ concept for Internet-connected metering. That bias, however, is likely to make me a little more critical on Dranetz-BMI as I perform this review to see how they have evolved the system.

The reason for choosing to review the 5590 DataNode® at this time is a practical one for me: I have a new client who has an urgent need for a permanent power quality monitoring system to evaluate the impact of their spot welding operations on their internal systems and on the utility’s system. I decided to kill two birds with one stone and evaluate the options for my client and report the results of one of the components in this review.

The 5590 DualNode™ is a very advanced power quality and quantity monitoring system designed for permanent installation that packs a huge amount of measurement capability and connectivity in a single package. The 5590 combines into a single enclosure both the Dranetz-BMI’s 5530 DataNode® (the pointy end of the stick that performs the actual measurements) and the 5500 Series InfoNode® (the field-hardened data concentrator and web-based reporting system).

It supports all of the key power quality measurement protocols including:

· IEC 61000-4-30 – basic power quality monitoring functionality

· IEC 61000-4-15 – light flicker measurement

· IEC 61000-4-7 – harmonics and interharmonics measurement

· IEEE 1159 – standardized power quality disturbance categorization and best practices

· IEEE 1159.3 (PQDIF) – standardized power quality data interchange format

The 5590 is able to capture detailed waveforms and rms traces of voltage and current during voltage sag events (the voltage depression that occurs when there is a short circuit on a system). This capability addresses the most common type of power quality event that is responsible for the bulk of end-use equipment failure. It is also one of very few instruments that measure flicker according to the 61000-4-15 standard correctly.

The 5590’s ability to be quickly installed on an Ethernet network and its built-in web interface allows even an occasional or novice user to quickly extract event and trend information from the system on demand. It uses Java technology to implement a rich, interactive user interface that minimizes the need for external PC based analysis software. Due to its support for the IEEE 1159.3 PQDIF standard, several third party programs can be used for advanced and specialized data analysis.

5590 DualNode™ compared to competitors

What separates the 5590 from its competitors (e.g. Electro Industries and Power Measurement) is (i) the modular nature of the system, (ii) support of advanced communication protocols (EPRI UCA2) in addition to Internet protocols, (iii) a very rich web-based user interface that eliminates the need for PC based software for all but the most detailed analysis, and (iv) its support for all relevant power quality measurement standards. The latter is particularly important. Some vendors claim support of an alphabet soup of power quality measurement standards, but not all pass detailed scrutiny in the lab. For example, many vendors claim support for the IEC 61000-4-15 light flicker measurement standard, but of 8 different manufacturers meters tested in our lab, only the Dranetz-BMI monitors passed the detailed 61000-4-15 test protocol developed by the Cigré voltage quality working group (a technical organization that feeds into the IEC standards process).

Where you need to be careful

The core communications technology employed by the 5590 is the EPRI UCA2 suite of protocols. UCA2 served as a starting point for the development of the IEC 61850 suite of protocols for substation automation application. While UCA2 is incredibly powerful and embodies many of the key principles of the IntelliGrid Architecture, the 5590 should be upgraded to support the final 61850 standard suite. Also, the built-in security is very basic and easily defeated. Other devices in its class have the same problem, however, and external solutions such as VPN and other third party security appliances can easily address this shortcoming.

SGN’s Smart Grid Checklist:

Dranetz-BMI claims to use state-of-the-art power quality and quantity measurement techniques and supports all relevant measurement standards and many Internet communication standards. Our analysis based on our metrics generally confirms this claim. In general, The Dranetz-BMI 5590 embodies key elements of the EPRI IntelliGrid Architecture, which we believe are key to implementing the Smart Grid through well-integrated applications:

► Service based architecture

► Technology layering and isolation and ability to be easily upgraded

► Well defined interfaces and points of interoperability

► Information models and discoverability

► Application of industry and international standards

► Distributed computing (modular, network connected components)

► Network and systems management

Dranetz-BMI 5590 DualNode™ Smart Grid Checklist scores -- total score of 76 (out of 100)

Metric	1-10 (10 is best)	Comments
Impact	8	It is one of few instruments providing a detailed view of the real time behavior of the power system.
Openness	7	The system supports many open communications standards that facilitate integration into larger systems. One of these -- EPRI UCA2 -- inherently supports automated discovery of system capabilities and available data. UCA2 is now defunct and unsupported; it was superseded by IEC 61850, which the 5590 does not currently support.
Standardization	8	The system supports all relevant power quality and quantity measurement standards and passes certification test for the most difficult of those standards (61000-4-15 flicker). Many of the communications standards it supports are outdated and need to be upgraded.
Security	4	The system components support the most basic authentication that is easily compromised by even a novice hacker. If data and operational security is important, external security methods such as VPN must be employed.
Manageability	7	The system does not support SNMP and must be remotely managed through the use of Internet File Transfer Protocol (FTP) and the web interface.
Upgradeability	10	The system supports multiple methods of upgrading firmware and software for all components.
Scalability	7	The slow 10 mbps Ethernet connection coupled with internal processing limitations make scaling system capacity a little more difficult than it should.
Extensibility	9	The Signature System Answer Modules allows the vendor to implement new functionality with a simple software upload.
Self-Healing	7	Industry standards techniques such as hardware watchdog timers and other methods are employed to ensure that the system can recover from unexpected internal system faults while minimizing data loss.
Interactivity	9	The built-in web interface is comprehensive and very easy to use. External PC based software is only needed for the most advanced analysis and permanent data archiving.
Total	76	The Dranetz-BMI 5590 DualNode™ doesn’t score as well as other Smart Grid products we have reviewed here, but it still sets a benchmark in its core functionality and connectivity that few if any can match.
Date of product: March 2004. 5590 DualNode™ Rev D

In closing, if you want to keep your finger on the pulse of your power system with the capability to inspect the details on demand, you can’t go wrong with the 5590 DualNode™. We hope that Dranetz-BMI will upgrade the system to implement the most recent network communications and security technologies. It appears that the new Dranetz-BMI Encore Series® system may provide a platform to do just that.

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

Email Erich W. Gunther

Smart Grid Scorecard (PDF)

EPRI IntelliGrid Architecture Web site

GridWise Architecture Council

Dranetz-BMI website

Electro Industries website

Schneider Electric Power Measurement website

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